Note: Descriptions are shown in the official language in which they were submitted.
SKATE BLADE SHARPENING SYSTEM
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Date Recue/Date Received 2022-04-05
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No. 1173-0171
BACKGROUND
Field of the Invention
[0012] The present
invention generally relates to machines configured to
sharpen blades for ice skates. More particularly, the present invention
relates to such
machines configured for automated sharpening of blades for ice skates.
Description of the Related Art
[0013] Ice skates
engage the surface of the ice on a pair of edges. Over time,
the edges can become dull or nicked and, in such conditions, the performance
of the ice
skates is less than optimal. To restore the performance of the ice skates, the
skate blades
can be sharpened.
[0014] While the
frequency of ice skate blade sharpening differs depending
upon the individual, the recommended frequency for most serious skaters is one
sharpening for every three to five hours of ice time. When it is time for the
sharpening,
few people have the equipment necessary to sharpen the skates and, for that
reason, the
skates need to be dropped off at a local skate shop or ice rink for
sharpening. The
frequent trips for sharpening can become an annoyance and many skaters will
skate on
less than optimal skate blades simply to avoid the extra trips or time in line
at the skate
shop or rink. Even if people had access to the equipment, few people have the
training or
skills necessary to sharpen their own skates.
SUMMARY OF EMBODIMENTS
[0015] A need
exists for skate sharpening machines that are simple to use and
cost effective enough for home use. Certain features, aspects and advantages
of the
present invention address a myriad of challenges encountered when designing a
portable
skate sharpening machine that is cost effective and easy to use.
[0016] Certain aspects of the disclosure provide a method of aligning a
grinding
component in a skate blade sharpening system. The method can include
positioning a first
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visual reference feature at a first predetermined location relative to at
least one jaw
configured to secure a skate blade within the skate blade sharpening system;
providing a
second visual reference feature at a second predetermined location on a motor-
driven
component, wherein the motor-driven component is movable within a housing of
the
skate blade sharpening system by an adjustment mechanism; and operating the
adjustment mechanism to position the motor-driven component such that the
second
visual reference feature is brought into alignment with the first visual
reference feature
thereby bringing into alignment the skate blade with the grinding component.
[0017] In some configurations, the first visual reference feature is
positioned at a
defined distance from a centerline of the at least one jaw when a skate blade
is secured
within the at least one jaw. In some configurations, the second visual
reference feature is
positioned at a defined distance from a centerline of a grinding portion of a
grinding
component when the grinding component is mounted on a mounting location of the
motor-driven component. In some configurations, the centerline of the grinding
component is at a maximum outer diameter of the grinding portion. In some
configurations, the alignment of the second visual reference feature with the
first visual
reference feature aligns the centerline of the grinding component with a
centerline of the
skate blade. In some configurations, positioning the first visual reference
feature at the
first predetermined location includes temporarily securing the first visual
reference
feature within the housing of the skate blade sharpening system. In some
configurations
the method includes positioning a magnifying lens configured to magnify a view
area of
the first visual reference feature and the second visual reference feature. In
some
configurations, a grinding component is configured to be removably mounted on
a
mounting location of the motor-driven component without adjusting the
alignment of the
motor-driven component. In some configurations, the first visual reference
feature is a
flag-like structure. In some configurations, the second visual reference
feature is
incorporated into the motor-driven component. In some configurations, the
second visual
reference feature is positioned on an arbor coupled to the motor-driven
component. In
some configurations, the second visual reference feature is a notch recessed
in an
alignment component coupled to the motor-driven component. In some
configurations,
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the alignment component has a noncircular shape. In some configurations, the
second
visual reference feature is on a grinding component coupled to the motor-
driven
component, wherein the grinding component comprises an alignment portion and a
grinding portion, wherein the grinding portion comprises an abrasive outer
layer. In some
configurations, the second visual reference feature is a notch recessed in the
alignment
portion. In some configurations, operating the adjustment mechanism to
position the
motor-driven component such that the second visual reference feature is
brought into
alignment with the first visual reference feature is performed by a controller
configured to
control the operation of the adjustment mechanism. In some configurations, the
method
includes comprising positioning the motor-driven component in an alignment
position
within the housing of the skate blade sharpening system prior to alignment.
[0018] In another embodiment, a skate blade sharpening system includes a
housing comprising at least one jaw configured to secure a skate blade; a
motor-driven
component configured to be movable within the housing of the skate blade
sharpening
system relative to the at least one jaw; a first visual reference feature
positioned within
the housing at a first predetermined location relative to the at least one
jaw; a second
visual reference feature positioned on the motor-driven component at a second
predetermined location; and an adjustment mechanism configured to position the
motor-
driven component such that the second visual reference feature is brought into
alignment
with the first visual reference feature.
[0019] In some configurations, the second visual reference feature is
positioned at
a defined distance from a centerline of a grinding portion of a grinding
component when
the grinding component is mounted on a mounting location on the motor-driven
component. In some configurations, the alignment of the second visual
reference feature
with the first visual reference feature aligns a centerline of the at least
one jaw with the
centerline of the grinding component when the grinding component is mounted to
the
mounting location. In some configurations, the second visual reference feature
is
positioned on an alignment component mounted on a mounting location on the
motor-
driven component. In some configurations, the second visual reference feature
is
incorporated into the motor-driven component. In some configurations, a
grinding
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component is configured to be removably mounted on a mounting location of the
motor-
driven component without adjusting the alignment of the motor-driven
component. In
some configurations, the second visual reference feature is on a grinding
component
coupled to the motor-driven component, wherein the grinding component
comprises an
alignment portion and a grinding portion, wherein the grinding portion
comprises an
abrasive outer layer. In some configurations, the system includes a controller
configured
to control operation of the adjustment mechanism and automatically position
the motor-
driven component such that the second visual reference is brought into
alignment with the
first visual reference feature.
[0020] In another embodiment, a skate blade sharpening system includes a
grinding component coupled to a motor for rotation, the grinding component
configured
to translate longitudinally relative to a bottom edge of a skate blade
retained by the skate
blade holder, the grinding component having an outer surface dimensioned and
configured to sharpen the bottom edge of the skate blade during a sharpening
operation,
and the grinding component including an identification tag having interface
circuitry
configured to communicate with electronic circuitry of the skate blade
sharpening system
and memory including a usage location configured to store a usage tracking
value. The
skate sharpening can also include electronic circuitry that can include a
transceiver
configured to communicate with the interface circuitry of the identification
ta.c4- and to
read from and write to the usage location; sharpening control circuitry
configured to
control operation of the grinding component and perform sharpening operations;
and
usage control circuitry configured to write, using the transceiver, an update
to the usage
tracking value based, at least in part, on usage of the grinding component
during
sharpening operations; read, using the transceiver, a current usage tracking
value from the
usage location; and control operation of the sharpening control circuitry for
sharpening
operations based, at least in part, on the current usage tracking value.
[0021] In some configurations, the usage control circuitry is further
configured to
selectively enable or disable operation of the sharpening control circuitry
for sharpening
operations. In some configurations, the usage tracking value indicates usage
of the
grinding component as a number of passes performed by the grinding component
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sharpening operations, wherein the electronic circuitry is configured to
update the usage
tracking value based, at least in part, on the number of passes performed by
the grinding
component. In some configurations, the usage location is further configured to
store a
usage limit value, the usage limit value indicates a maximum number of passes
a grinding
component can complete, wherein the grinding component includes a metal
grinding ring
having an outer surface with an abrasive layer thereon, the abrasive layer
having a defined
lifetime, and wherein the usage limit value corresponds to a period of use of
the abrasive
layer that is less than the defined lifetime of the abrasive layer. In some
configurations,
the usage control circuitry is further configured to determine whether a usage
threshold of
the grinding component has been satisfied based, at least in part, on a
relationship
between the current usage tracking value and the usage limit value. In some
configurations, the memory of the identification tag is further configured to
include one
or more system setup parameter locations for storing system setup parameters,
and
wherein the interface circuitry is further configured to provide the system
setup
parameters from the system setup parameter locations to the electronic
circuitry of the
sharpening system to be applied to setup parameters of the sharpening system.
In some
configurations, the system setup parameters comprise operating parameters
having
deteimined values for the specific grinding component, wherein the operating
parameters
include one or more of a grinding motor rotation speed, a translation speed,
or a normal
grinding force. In some configurations, the memory of the identification tag
is further
configured to include one or more user setting locations for storing user-
specific default
settings for parameters of a sharpening operation, and wherein the interface
circuitry is
configured to provide the user-specific default settings to the electronic
circuitry to by
applied to control a sharpening operation. In some configurations, the memory
of the
identification tag is further configured to include one or more fault
information locations
for storing fault data describing one or more fault conditions occurring
during a
sharpening operation using the grinding component, the fault information
locations being
readable by a separate reader used in a fault diagnosis, and wherein the
interface circuitry
is configured to (i) receive from the electronic circuitry particular fault
data identifying an
occurrence of a particular fault during a sharpening operation, and (ii) write
the particular
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fault data to the fault information locations. In some configurations, the
interface circuitry
provides a wireless interface for wireless communication between the
transceiver and the
identification tag. In some configurations, the identification tag is located
within the
grinding component such that the identification tag rotates with the grinding
component
during the sharpening operation, and wherein the interface circuitry is
configured to
engage in the wireless communication with the transceiver during the
sharpening
operation as the grinding component rotates. In some configurations, the
grinding
component includes a metallic ring having an abrasive-coated outer surface for
contacting
a blade to be sharpened during sharpening operations; and a generally disk-
shaped hub
carrying the identification tag and to which the metallic ring is fixedly
mounted, the hub
and ring being configured for mating with an arbor on a rotating shaft of the
sharpening
system. In some configurations, the metallic ring circumscribes a cylindrical
region in
which at least part of the hub is located, the cylindrical area extending
between first and
second axial ends of the metallic ring; the interface circuitry of the
identification tag
provides a wireless interface for wireless communication between the
transceiver and the
identification tag; and the identification tag is mounted to the hub in a
manner to reduce
an effect of the metallic ring on the wireless communication between the
transceiver and
the identification tag. In some configurations, the grinding component is a
grinding
wheel. In some configurations, the grinding component includes a hub of a non-
metallic
material, the hub carrying the identification tag. In some configurations, an
axial end of
the hub includes a user-inaccessible covered cavity in which the
identification tag is
located.
[0022] In another embodiment, a method of operating a skate blade sharpening
system can include performing at least one sharpening operation with a
grinding
component using the skate blade sharpening system, wherein a motor-driven
component
housed within the skate blade sharpening system translates the grinding
component
longitudinally along a bottom edge of a skate blade retained by a skate blade
holder, the
grinding component having an outer surface dimensioned and configured to
sharpen the
bottom edge of the skate blade, and the grinding component including an
identification
tag having interface circuitry configured to communicate wirelessly and memory
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including a usage location configured to store a usage tracking value;
communicating,
using a transceiver of the skate blade sharpening system, with the interface
circuitry of the
identification tag to write an updated usage tracking value to the usage
location based, at
least in part, on usage of the grinding component during the at least one
sharpening
operation, communicating, using the transceiver, with the interface circuitry
of the
identification tag to read the updated usage tracking value from the usage
location, and
controlling operation of the sharpening control circuitry for sharpening
operations based,
at least in part, on the updated usage tracking value.
[0023] In some configurations, controlling operation of the sharpening control
circuitry comprises enabling or disabling operation of the sharpening control
circuitry. In
some configurations, usage of the grinding component during the at least one
sharpening
operation comprises a number of passes performed by the grinding component
during the
sharpening operation, and the updated usage tracking value is based, at least
in part, on
the number of passes performed by the grinding component during the at least
one
sharpening operation. In some configurations, controlling operation of the
sharpening
control circuitry for sharpening operations is based, at least in part, on the
updated usage
tracking value further includes comparing the updated usage tracking value to
a usage
limit value stored in the usage location of the identification tag, wherein
the usage limit
value indicates a maximum number of passes a grinding component can complete;
and
determining whether a usage threshold of the grinding component has been
exceeded
based, at least in part, on a relationship between the updated usage tracking
value and the
usage limit value. In some configurations, the can include, prior to
performing the at least
one sharpening operation, communicating with the identification tag to access
at least one
system setup parameter; and configuring the skate blade sharpening system in
accordance
with the at least one setup parameter. In some configurations, the method can
include,
prior to performing the at least one sharpening operation, communicating with
the
identification tag to access at least one operating parameter associated with
the operation
of the grinding component; and performing the at least one sharpening
operation with the
grinding component in accordance with the at least one operating parameter. In
some
configurations, the method can include, prior to performing the at least one
sharpening
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operation, communicating with the identification tag to access at least one
user-specific
default setting for parameters of the sharpening operation; and performing the
at least one
sharpening operation with the grinding component in accordance with the at
least one
user-specific default setting for parameters of the sharpening operation.
[0024] In another embodiment, a skate blade sharpening system can include a
housing having a slot configured to receive a skate blade in a sharpening
position; a
grinding component configured for movement along the slot at a lower edge of
the skate
blade during a sharpening operation; at least one slot cover movable between
an
occluding position and a non-occluding position along the slot; at least one
sensing
component configured to determine engagement of the at least one slot cover
with the
skate blade: wherein in the non-occluding position the at least one slot cover
permits
insertion and removal of the skate blade, wherein in the occluding position
the at least
one slot cover engages at least one end of the skate blade and limits access
through at
least a portion of the slot; and a controller of the skate blade sharpening
system
configured to control operation of the grinding component based, at least in
part, on at
least one indication received from the at least one sensing component.
[0025] In some configurations, the controller is further configured to prevent
a
sharpening operation based, at least in part, on an indication received from
the at least one
sensing component that the at least one slot cover is positioned in the non-
occluding
position. In some configurations, the skate blade sharpening system can
include a dust
pan switch configured to determine whether a dust pan is positioned within the
chassis of
the skate blade sharpening system, wherein the controller is further
configured to prevent
operation of the skate blade sharpening system when the dust pan is not
positioned within
the chassis. In some configurations, the skate blade sharpening system can
include a door
configured to provide access to an interior of the chassis and a door switch
configured to
determine whether the door is in an open position or a closed position,
wherein the
controller is further configured to prevent operation of the skate blade
sharpening system
when the door is in the open position. In some configurations, the skate blade
sharpening
system can include a lighting component configured to provide a visual
indication
indicative of an operational state of the skate blade sharpening system. In
some
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configurations, the lighting component is configured to provide different
visual
indications for different operational states. In some configurations, the
lighting
component is a light-emitting diode. In some configurations, the at least one
sensing
component is included in the at least one slot cover. In some configurations,
the at least
one sensing component includes a mechanical member moving between a first
position
and a second position, the mechanical member configured to be in the first
position when
the at least one slot cover is not engaged by the skate blade, the mechanical
member
configured to be in the second position when the at least one slot cover is
engaged by the
skate blade. In some configurations, the mechanical member includes a switch-
engaging
portion, wherein the at least one sensing component further includes an
electrical switch
engaged by the switch-engaging portion when the mechanical member is in the
first
position, and the indication provided by the at least one sensing component
indicates an
electrical state of the electrical switch. In some configurations, in the
first position, the
indication provided by the at least one sensing component is an open
electrical state, and
in the second position, the indication provided by the at least one sensing
component is a
closed electrical state. In some configurations, the mechanical member is a
bumper
having a face portion configured to be pushed by the skate blade to move the
bumper
from the first position to the second position. In some configurations, the at
least one slot
is positioned on top of the housing. In some configurations, the grinding
component is a
grinding wheel.
[0026] In another embodiment, a method of operating a skate blade sharpening
system can include receiving, by a controller, an indication from a sensing
component of
a position of at least one slot cover, wherein the at least one slot cover is
mounted relative
to a slot of a housing, the slot configured to receive a skate blade in a
sharpening position,
the at least one slot cover movable between an occluding position and a non-
occluding
position along the slot, wherein a grinding component is positioned within the
housing
and configured for movement along the slot at a lower edge of the skate blade
during a
sharpening operation; determining, by the controller, whether the at least one
slot cover
is positioned in the occluding position based, at least in part, on the
indication from the
sensing component, wherein in the non-occluding position the at least one slot
cover
[0027a] According to an aspect of the invention is a method of
aligning a grinding
component in a skate blade sharpening system, the method comprising:
retaining an alignment tool with at least one jaw, the at least one jaw
configured
to secure a skate blade within the skate blade sharpening system in a
sharpening position,
the sharpening position having a centerline, the alignment tool comprising a
first
reference feature positioned at a defined position relative to the centerline
of the
sharpening position;
providing a second reference feature at a second predetermined location on a
motor-driven component, wherein the motor-driven component is movable within a
housing of the skate blade sharpening system by an adjustment mechanism; and
operating the adjustment mechanism to position the motor-driven component such
that the second reference feature is brought into alignment with the first
reference feature
thereby bringing into alignment the skate blade with the grinding component.
10027b] According to a further aspect is a skate blade sharpening
system
comprising:
a housing comprising at least one jaw configured to secure a skate blade in a
sharpening position, the sharpening position having a centerline;
a motor-driven component configured to be movable within the housing of the
skate blade sharpening system relative to the at least one jaw;
an alignment tool having a first reference feature, the alignment tool
releasably
retained within the housing by the at least one jaw, the first reference
feature positioned
at a defined position relative to the centerline of the sharpening position;
a second reference feature positioned on the motor-driven component at a
second
predetermined location; and
an adjustment mechanism configured to position the motor-driven component
such that the second reference feature is brought into alignment with the
first reference
feature.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0028] These and other features, aspects, and advantages will be
apparent
from the following description of particular embodiments, as illustrated in
the
accompanying drawings in which like reference characters refer to the same
parts
throughout the different views.
[0029] Figure 1 is a perspective view of a skate sharpening system;
[0030] Figure 2 is a schematic depiction of a grinding wheel contacting
a
skate blade during sharpening;
[0031] Figure 3 is a perspective view of a metal frame and chassis of a
sharpening system;
[0032] Figure 4 is a perspective view of an interior of a sharpening
system
including a carriage assembly;
[0033] Figure 5 is a perspective view of a skate blade clamp;
[0034] Figure 6 is a block diagram of an electrical subsystem of a skate
sharpening system;
[0035] Figures 7 and 8 are front elevation views of a sharpening system;
[0036] Figure 9 is an exploded perspective view of a grinding wheel;
[0037] Figure 10 is a perspective view of an interior of a sharpening
system
including a carriage assembly;
[0038] Figure 11 is a rear view of a rear part of a radio frequency
identification (RFID) antenna housing in a sharpening system;
[0039] Figure 12 is a perspective view of an arbor;
[0040] Figure 13 is a front elevation view of a carriage assembly;
[0041] Figure 14 is a side elevation view of a carriage assembly;
[0042] Figure 15 is a flow diagram of operation of a sharpening system--
;
[0043] Figure 16 is a section view of the platform area of the chassis;
[0044] Figures 17 and 18 are plan views of clamping jaws;
[0045] Figures 19, 20 and 21 are section views of clamping jaws and
guide
blocks;
[0046] Figure 22A is a bottom view of a slot cover;
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[0047] Figure 22B is another bottom view of the slot cover:
[0048] Figure 22C is a perspective view of the slot cover;
[0049] Figure 22D is an end view of the slot cover and a portion of the
platform area;
[0050] Figure 23 is a section view of one end of a carriage assembly;
[0051] Figure 24 is a close-up view of a portion of Figure 23;
[0052] Figure 25 is a schematic depiction of alignment between clamping
jaws and a grinding wheel;
[0053] Figure 26 is a side elevation view of an alignment tool in use;
[0054] Figure 27 is a plan view of an alignment tool in use;
[0055] Figure 28 is a flow diagram of an alignment process;
[0056] Figure 29 is a perspective view of a grinding ring, which is
useable
alone or in an assembly as a portion of a grinding wheel;
[0057] Figure 30 is a perspective view of an arrangement having an
alignment
wheel mounted on a spindle;
[0058] Figure 31 is a perspective exploded view of arrangement of Figure
30;
[0059] Figure 32 is a schematic depiction of alignment between clamping
jaws and an alignment wheel;
[0060] Figure 33 is a side elevation view of an alignment tool in use
with an
alignment wheel;
[0061] Figure 34 is a plan view of an alignment tool in use with an
alignment
wheel;
[0062] Figure 35 is a flow diagram of an alignment process using an
alignment wheel;
[0063] Figure 36 is a perspective view of a skate sharpening system;
[0064] Figure 37 is a front view of the skate sharpening system of
Figure 36;
[0065] Figure 38 is a right end view of the skate sharpening system of
Figure
36;
[0066] Figure 39 is a left end view of the skate sharpening system of
Figure
36;
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[0067] Figure 40 is a rear view of the skate sharpening system of Figure
36;
[0068] Figure 41 is a top view of the skate sharpening system of Figure
36;
[0069] Figure 42 is a bottom view of the skate sharpening system of
Figure
36;
[0070] Figure 43 is a bottom view of a skate clamping mechanism;
[0071] Figure 44 is a front sectioned view of a skate clamping mechanism
taken along the line 44-44 in Figure 43;
[0072] Figure 45 is a bottom view of a skate clamp;
[0073] Figure 46 is a front sectioned view of the skate clamp of Figure
45
taken along the line 46-46 in Figure 45;
[0074] Figure 47 is an exploded perspective view of the skate clamp of
Figure
45;
[0075] Figure 48 is a top view of the skate clamp of Figure 45;
[0076] Figure 49 is a front view of the skate clamp of Figure 45
together with
a carriage and grinding wheel;
[0077] Figure 50 is a top view of a slot cover;
[0078] Figure 51 is a perspective bottom view of the slot cover of
Figure 50;
[0079] Figure 52 is a sectioned end view of the slot cover of Figure 50
together with a front platform portion of the chassis of the skate sharpening
system;
[0080] Figure 53 is a top view of the slot cover of Figure 50 together
with the
front platform portion of the chassis and skate clamp of the skate sharpening
system;
[0081] Figure 54 is a perspective view of a slot cover;
[0082] Figure 55 is an exploded perspective view of the slot cover of
Figure
54;
[0083] Figure 56 is a top view of a bottom portion of the slot cover of
Figure
54;
[0084] Figure 57 is a left end view of another slot cover together with
the
front platform portion of the chassis;
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[0085] Figure 58 is a top left perspective view of the slot cover of
Figure 57
with the top portion of the slot cover removed and positioned on the front
platform
portion of the chassis;
[0086] Figure 59 is a top view of the slot cover of Figure 57 and front
platform portion of the chassis;
[0087] Figure 60 is a right end view of a portion of the chassis and the
carriage assembly;
[0088] Figure 61 is a front left perspective view of the carriage
assembly of
Figure 60;
[0089] Figure 62 is a top view of a portion of the carriage assembly of
Figure
60;
[0090] Figure 63 is a top view of a portion of the carriage assembly of
Figure
60;
[0091] Figure 64 is a sectioned view of the portion of the carriage
assembly of
Figure 63 taken along the line 64-64 in Figure 63;
[0092] Figure 65 is a front right perspective view with the right end
cap
removed to illustrate a stepper motor configuration;
[0093] Figure 66 is a top view of the skate sharpening system of Figure
36
with a portion of the platform removed to expose the carriage assembly and
drive belt
assembly;
[0094] Figure 67 is a perspective view of a grinding wheel construction;
[0095] Figure 68 is a front view of the grinding wheel construction;
[0096] Figure 69 is a top view of the grinding wheel construction (the
bottom
view, left view and right view will be identical);
[0097] Figure 70 is a rear view of the grinding wheel construction;
[0098] Figure 71 is a sectioned view of the grinding wheel construction
taken
along the line 71-71 in Figure 70;
[0099] Figure 72 is an exploded perspective view of the grinding wheel
construction of Figure 67;
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[0100] Figure 73 is
a sectioned perspective view of the grinding wheel
construction of Figure 67;
[0101] Figure 74 is
a sectioned perspective view of the grinding wheel
construction of Figure 67;
[0102] Figure 75 is
an exploded sectioned perspective view of a hub assembly
of the grinding wheel of Figure 67;
[0103] Figure 76 is
a sectioned top view of the skate sharpening system of
Figure 36 taken along the line 76-76 in Figure 37;
[0104] Figure 77 is
an exploded perspective view of certain components of an
air filtration and dust capture system of the skate sharpening system of
Figure 76;
[0105] Figure 78 is
front left perspective view with the left end cap removed
to illustrate a blower configuration;
[0106] Figure 79 is
a sectioned view of a portion of the skate sharpening
system of Figure 36;
[0107] Figure 80 is
a view of an inside of the right end wall and illustrating
the location and construction of two switch assemblies, which switch
assemblies are
shown separate of a supporting frame;
[0108] Figure 81 is
another view of the slot cover of Figure 50 with a youth
skate adaptor installed; and
[0109] Figure 82 is
a rear perspective view of the youth skate adaptor showing
the snap fit features used to secure the youth skate adaptor to the slot cover
of Figure 50.
[0110] Figure 83 is
an embodiment of a chart illustratimg an example of power
consumed by a grinding motor during a grinding operation.
[0111] Figure 84 is
an embodiment of a chart illustrating an example of power
consumed by a grinding motor during a grinding operation.
[0112] Figure 85
illustrates an embodiment of a flowchart for execution of a
soft start routine.
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DETAILED DESCRIPTION OF EMBODIMENTS
[0113] Figure 1 is
a perspective view of a skate sharpener 10 used to sharpen
the blades of ice skates. As illustrated, the skate sharpener 10 is designed
and configured
to provide a safe, clean and automated skate sharpening system that allows
anyone to
sharpen skates at home, on their own schedule, and with professional quality
results. A
second skate sharpener 1010 is shown in Figure 36. The second skate sharpener
1010,
which being largely the same configuration as the skate sharpener 10 in Figure
1, has
some differences that will be discussed throughout this application. The
similarities,
however, will not be described in detail. Many of the structures of one skate
sharpener
10, 1010 can be used with the other interchangeably and, thus, it is possible
to construct a
skate sharpener using certain features of one embodiment with certain features
of another
embodiment and such combinations are expressly contemplated to be within the
scope of
this disclosure.
Skate Sharpener Overview
[0114] The
illustrated skate sharpener 10 has a box-like housing with
structural elements including a rigid frame 12 (bottom visible in Figure 1)
and a rigid
chassis 14. Attached components include end caps 16 and a rear cover 18. The
chassis 14
includes a front platform portion 22, also referred to as "platform" 22
herein. The
platform 22 includes an elongated slot 24 for receiving the blade of an ice
skate for
sharpening, and the blade is retained by clamp jaws (not shown) on the
underside of the
platform 22 which are actuated by a mechanism including a clamp paddle 26.
Disposed
on the platform 22 are slot covers or "scoops" 28 at respective ends of the
slot 24, each
including a respective bumper 29 serving to sense contact with a skate blade
holder. An
outward-opening door 30 having a glass panel 31 and lower hinge portion 33
extends
across a front opening. A user interface display panel 34 is disposed at top
right on the
chassis 14. The skate sharpener 10 also includes a control module or
controller, which is
not visible in Figure 1 and may he located, for example, inside of the rear
cover 18.
Further mechanical and electrical details are provided below.
[0115] Figure 1
also shows a coordinate system 35 for references to spatial
directions herein. The X direction is left-to-right, the Y direction front-to-
back, and the Z
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direction bottom-to-top with respect to the skate sharpener 10 in the upright,
front-facing
orientation of Figure 1. This coordinate system also defines an X-Y plane
(horizontal), X-
Z plane (vertical and left-to-right), and Y-Z plane (vertical and front-to-
back). Using this
coordinate system 35, the slot 24 extends in the X direction and the skate
blade is
clamped in an X-Z plane during sharpening as described more below.
[0116] Figure 2
depicts how a skate blade is sharpened. This is a schematic
edge-on view of a lower portion of a skate blade 40 in contact with an outer
edge of a
grinding wheel 36. With reference to the coordinate system 35, this is a view
in the X
direction. As shown, the grinding wheel 36 has a convex rounded grinding edge
42. In
practice the grinding edge 42 may be generally hemispherical. The grinding
wheel 36
rotates in the plane of the blade 40 (X-Z plane, into the paper in Figure 2),
thereby
imparting a corresponding concave rounded shape to a lower face 44 of the
skate blade
40. Two acute edges 46 are formed at the intersection of the curved lower face
44 and the
respective sides 48 of the blade 40. As material is removed, a clean and
precise arcuate
shape is restored to the lower face 44, including sharper edges 46. In
practice, the radius
of curvature of the lower face 44 is in the general range of 3/8" to 1", with
one generally
preferred radius being 1/2". It will be appreciated that the disclosed methods
and
apparatus may be used with other blade profiles, including flat and V-shaped,
for
example.
Method of Using the Skate Sharpener
[0117] Returning to
Figure 1, basic operation with a complete skate is as
follows. First a user may need to install a grinding wheel onto an internal
carriage (not
shown) accessible via the front opening. For this the user opens the door 30,
rotating it
forward and downward about the horizontal hinge 33, and then closes the door
after
successfully installing the grinding wheel. The nature of the installation
will be apparent
from the more detailed description below. The user then clamps the blade of
the skate in
the slot 24 and slides the scoops 28 inwardly until the bumpers 29 are engaged
by the
blade holder part of the skate. Each bumper 29 actuates a limit switch within
the
respective scoop 28, so that the engagement is sensed by the controller to
enable
sharpening to proceed. The user then interacts with a user interface presented
on the
18
display panel 34 to initiate a sharpening operation. Subject to certain
conditions as described
more below, control circuitry of the control unit automatically operates both
a grinding motor to
spin a grinding wheel and a separate carriage motor (both described below) to
move the rotating
grinding wheel back and forth along the lower face of the skate blade a
desired number of times.
Each traversal of the grinding wheel across the length of the blade is
referred to as a "pass". In
each cycle of two passes (one to the left and the other to the right), the
grinding wheel is moved
to a far-right position at one end of the skate blade to permit a
communications exchange
between circuitry on the wheel and the control unit. This communication and
related control are
described below. Upon completion of a desired number of passes, the control
unit stops both the
rotation and back-and-forth motion of the wheel 36, and the user unclamps and
removes the
skate blade from the sharpener 10. It is noted that controls and locations
could be reversed in
alternative embodiments, so that the communications position would be a far-
left position rather
than a far-right position.
[0118] The above operation may also be used with bare removable
skate blades of
the type known in the art. In this case a blade holder or other mechanical aid
of some type may
be used to enable a user to position the bare blade in the slot 24 for
clamping and to engage the
bumpers 29 of the scoops 28 to permit operation. For example, the blade may be
secured in a
blade holder such as that described in co-pending U.S. Patent Application No.
14/632,862, filed
February 26, 2015, and U.S. Patent Application No. 14/632,868, filed February
26, 2015.
Alternatively, a bare blade could also be positioned without a blade holder.
As described more
below, a blade holder may engage limit switches on the slot covers 28 to
enable sharpening
operation, and enables a user to insert a loose skate blade in clamping jaws.
Grinding Wheel Translation and Vertical Movement
[0119] Figure 3 is a view of the frame 12 and chassis 14. In one
embodiment, the
frame 12 is made of a single piece of sheet metal, folded to form a bottom 50,
sides 52 and back
54. The chassis 14 serves as a top for the sharpener 10 and provides support
for key components
including a skate clamp and a carriage assembly, both described
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below. The chassis 14 is a rigid component made of metal or other suitably
strong
material. In one embodiment, the chassis 14 is made of aluminum and formed by
extrusion, which can provide very accurate dimensions and geometry in a highly
repeatable manner. The chassis 14 may be made of other materials and by other
methods,
including machining for example, in alternative embodiments.
[0120] As shown,
the chassis 14 has an S-like cross section defining the
frontward platform 22 and a rearward shelf portion ("shelf") 56 separated by a
sloping
wall 58. The underside of the shelf 56 includes two rails 60 on which a
carriage (not
shown) moves, as well as a downward- projecting flange 62. As described more
below, a
toothed "gear rack" that forms part of a rack- and-pinion mechanism for moving
the
carriage is attached to the flange 62. On the platform 22 at each end of the
slot 24 are
rounded projections 64 on which the scoops 28 are slidably mounted. The
projections 64,
also referred to as "arches" 64 below, have retention grooves 66 that engage
with
corresponding features in the scoops 28 to retain the scoops 28 on the
projections 64
while permitting them to slide left and right.
[0121] Figure 4
shows the sharpener 10 with several external components
removed. The 4-sided sheet metal frame 12 is fully visible. A carriage
assembly 70
includes a carriage 72 mounted on the two rails 60, which are shown as
separated from
the rest of the chassis 14 in this view. The carriage assembly 70 includes a
pivoting motor
arm 78 to which a grinding wheel motor 80 is mounted. The grinding wheel 36 is
mechanically coupled to the rotating shaft of the motor 80 by an elongated
spindle 82.
The motor arm 78 has limited rotational travel about a horizontal pivot axis
83, so that
the grinding wheel 36 can move in a vertical direction to follow the profile
of a skate
blade when the sharpener 10 is in operation. In the illustrated embodiment,
the motor arm
78 is biased toward an upper vertical limit by a spring 84 connected between
the motor
arm 78 and an upper portion of the carriage 72.
[0122] One
important feature of the presently disclosed skate sharpener 10 is
use of a compact (small-diameter) grinding wheel 36. Specifically, its
diameter is less
than the diameter of the grinding wheel motor 80 by which it is rotated. Use
of a compact
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grinding wheel 36 can provide certain advantages including greater precision
in operation
and lower cost.
[0123] Also shown
in schematic fashion in Figure 4 is a wire harness 86
providing electrical connections between the grinding wheel motor 80 and the
above-
mentioned controller as well as between the controller and a carriage motor
mounted
within the carriage 72 (not visible in Figure 4). In Figure 4 the wire harness
86 is shown
separate from the rest of the unit for ease of illustration, but it is
actually located inside
the unit along the rear wall 54. It preferably is self- supporting along its
length in a
manner that maintains its vertical position while permitting back- and-forth
movement of
the connectors attached to the carriage assembly 70. An example of a suitable
support
element is a ribbon-like material of the type used in printers and other
machines with
translating components. This material can flex about a transverse axis while
being stiff
about a longitudinal axis, and thus can maintain horizontal straightness while
also flexing
in a desired curling manner about a vertical axis that follows movement of the
carriage
assembly 70.
[0124] In
operation, the grinding wheel 36 is rotated by the grinding wheel
motor 80 via the spindle 82, and the carriage assembly 70 is moved back and
forth along
the rails 60 by action of a rack-and-pinion mechanism that includes a motor-
drive pinion
gear 87 engaging a toothed rack on the underside of the chassis 14 (described
more
below). The pinion gear 87 is driven by a carriage motor mounted within the
carriage 72,
not visible in Figure 4. Each unidirectional pass of the grinding wheel 36
begins with the
grinding wheel 36 located off one end of the skate blade and at the upper
vertical limit
position by action of the spring 84. As the carriage assembly 70 is moved
toward the
opposite end of the sharpener 10, the grinding wheel 36 encounters an end of
the skate
blade and is deflected downward to follow the profile of the skate blade
across its length.
At the end of the pass, the wheel 36 rides off the other end of the skate
blade and returns
to the vertical limit position by action of the spring 84.
Clamping Mechanism
[0125] Figure 5
shows the underside of the chassis 14. It includes a skate
blade clamping mechanism whose major components are a pair of clamp jaws 90,
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specifically a front jaw 90-F and a rear jaw 90-R; a pull rod fork 92; a clamp
cylinder 94;
and a cam 96 at the underside of the clamp paddle 26 that rotates therewith.
The clamp
cylinder 94 is retained by a bracket 98. Also shown is a jaw guard 100. The
clamp
cylinder 94 has a pull rod 102 connected to the pull rod fork 92 and an
internal spring-
piston arrangement that actuates the pull rod 102 and thus the jaws 90 via the
pull rod
fork 92.
[0126] As shown,
the jaws 90 each include angled slots 104, and in the slots
104 are arranged rectangular guide blocks 106 that retain the jaws 90 at the
underside of
the platform 22 with spacing to permit the jaws 90 to slide in the long
direction of the
slots 104. The front jaw 90-F is retained by one guide block 107 in a center
slot 104,
while the rear jaw 90-R is retained by respective guide blocks 106 in outer
two slots 104.
This arrangement permits the front jaw 90-F to rotate very slightly about a Z-
direction
axis extending through the single guide block 106, while the rear jaw 90-F is
rotationally
fixed. Additional details are provided below.
[0127] When the
clamp paddle 26 is in the position shown in both Figure 5
and Figure 1, i.e., extending horizontally away from the platform 22, the cam
96 does not
engage the internal piston of the clamp cylinder 94, and the action of the
internal spring is
to retract the pull rod 102 (toward the left in Figure 5) so that the jaws 90
are brought
toward each other by action of the angled slots 104 and guide blocks 106, 107.
This is a
referred to as a "closed" position, in which the jaws 90 are either just
touching each other
or are only slightly spaced apart, less than the width of the thinnest skate
blade to be
sharpened. Because this position is created by the spring alone, it is
referred to as a
"biased closed" position.
[0128] When a skate
blade is to be clamped for sharpening, a user rotates the
clamp paddle 26 to open the jaws 90. Referring to Figure 1, the user pushes
downward on
the outer part of the clamp paddle 26. In Figure 5, the clamp handle 26
rotates out of the
page, rotating the cam 96 accordingly and causing it to push against the
piston within the
clamp cylinder 94. This force works against the spring bias to extend the pull
rod 102 and
push on the jaws 90, causing them to move away from each other by action of
the angled
slots 104 and guide blocks 106, 107. The space between the jaws in the open
position is
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wider than the widest skate blade to be sharpened. The cam 96 and head of the
piston
may be co-configured to establish a detent with the jaws in the fully open
position. The
skate blade is then inserted through the slot 24 between the jaws 90, and the
user then
rotates the clamp paddle 26 upwardly (Figure 1) to close the jaws 90 on the
skate blade. It
will be appreciated that the front jaw 90-F automatically rotates as necessary
to close
snugly against the skate blade with balanced force across the length of the
jaws 90. In the
absence of this rotating feature, any imperfection in alignment of the jaws 90
could create
undesirable binding and/or rotational skewing of the skate blade, adversely
affecting
sharpening operation.
[0129] The jaw
guard 100 protects against the possibility of contact between
the grinding wheel 36 and the jaws 90. If the sharpener 10 were to somehow be
operated
without a skate blade present, then without the jaw guard 100 the wheel 36
would move
across the jaws 90 at its upper vertical limit position, potentially damaging
the grinding
wheel 36 and/or the jaws 90. The likelihood of this occurring can be reduced
or
eliminated by the jaw guard 100, which would be encountered by the spindle 82
(Figure
4) and keep the grinding wheel 36 in a more downward position safely away from
the
jaws 90.
[0130] Also shown
in Figure 5 is the above-mentioned rack 120 that is part of
the rack-and- pinion mechanism for moving the carriage 70, as mentioned above.
In the
illustrated embodiment it is an elongated member, of a material such as metal
or plastic,
attached to the flange 62. In an alternative embodiment, the rack 120 could be
formed by
machining or otherwise forming a toothed pattern in the flange 62 or similar
feature of the
chassis 14. In yet other alternative embodiments, a different type of
mechanism such as a
belt drive might be used to move the carriage 70.
Electronics and Electrical
[0131] Figure 6 is
an electrical block diagram of the skate sharpener 10. A
control unit 32 includes a processor 130 and one or more controllers 132. The
controllers
132 provide lower- level control of corresponding elements, such as the
grinding wheel
motor 80, a carriage motor 134, and a fan 136. Also shown are the user
interface (UI)
display panel 34 and RFID interface circuitry 137 in radio communications with
an
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identification tag 204 of the grinding wheel 36 (described more below). In
addition,
sensors and other components (e.g., switches) can also be connected to the
control 32.
For example, sensors or switches, as will be discussed below, can be used to
detect
whether a skate is properly positioned for sharpening, whether the door 30 has
been
opened or is closed, whether a dust tray or filter member is properly
positioned or the
like. The information from these sensors and other components can be used to
better
control operations of the skate sharpener to provide improved performance or
safer
operation.
[0132] Both the
controllers 132 and processor 130 are computerized devices
including memory, I/0 interface circuitry and instruction processing circuitry
for
executing computer program instructions stored in the memory. The controllers
132 may
be specialized for low-level real-time control tasks such as achieving and
maintaining a
commanded rotational speed for a motor. The processor 130 may have a more
generalized
architecture and potentially richer set of programming resources to perform a
variety of
higher-level tasks, includimg interfacing to a user via the UI display panel
34. The
processor 130 executing instructions of a particular computer program may be
viewed as
circuitry for performing functions defined by the program. For example, the
processor
executing instructions of a sharpening operation controller may be referred to
as
sharpening control circuitry, and the processor executing instructions related
to usage
control may be referred to as usage control circuitry. As mentioned above with
reference
to Figure 1, the controller 32 may be located within the rear cover 18.
[0133] Figures 7
and 8 are front views illustrating the above operation. A
skate 140 is present and its blade 142 is clamped into a sharpening position
in which the
lower portion of the blade 142 extends downward through the slot 24 (Figure 1)
into the
interior of the sharpener 10. In Figure 7 the carriage assembly 70 is located
at far left, and
the grinding wheel 36 is at an upper vertical limit position just off the left
(leading) edge
of the skate blade 142. Figure 8 shows the carriage assembly 70 and grinding
wheel 36 in
the middle of a pass. It can be seen that the grinding wheel 36 has moved
downward as it
has followed the profile of the blade 142. As mentioned, this left-to-right
pass ends with
the grinding wheel 36 at the far right, off the right (trailing) edge of the
blade 142.
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Generally multiple passes are used in a sharpening operation for a Oven blade
142, with
the number of passes being determined by the amount of material removal that
is
necessary to achieve desired sharpness. The sharpener may use both left-to-
right and
right-to-left passes in sequence, i.e., the grinding wheel 36 travels back and
forth in
contact with the blade 142 in both directions. Assuming a single home position
at one
end, in practice each sharpening operation may have a number of two-pass
cycles, each
including a pass in one direction and a pass in the opposite direction. In
alternative
embodiments sharpening may occur in only one direction, i.e., the grinding
wheel 36 is in
contact with the skate blade 142 only for passes in one direction, which
alternate with
non-sharpening return passes in the other direction.
Grinding Wheel
[0134] Figure 9
shows details of the grinding wheel 36 in one embodiment. It
is a multi-piece removable assembly that includes a metal grinding ring 200
disposed on a
rigid hub 202, such as by a press fit. The hub 202 has a shallow front-facing
cavity 203
which receives an identification tag 204 and a tag capture disk 206. The
identification tag
204 (and an optional graphic label not shown in Figure 9) is covered by the
capture disk
206, which has a snap-fit to the hub 202. The identification tag 204 may be
adhered to the
hub 202. Once the capture disk 206 is snapped onto the hub 202, disassembly is
very
difficult. In one embodiment the hub 202 and disk 206 are formed of
thermoplastic or
similar hard non-metallic material, and may be substantially transparent. The
grinding
wheel 36 is mounted to an axle 208 of the spindle 82 by a retention nut (not
shown) that
urges the grinding wheel 36 against a metal arbor 212 that forms part of the
spindle 82.
[0135] The grinding
ring 200 has an abrasive outer surface for removing
material from a skate blade during operation. In one embodiment the abrasive
surface
may include a diamond or cubic boron nitride (C,BN) coating, deposited by
electroplating
for example. The grinding ring 200 is preferably of steel or similar rigid,
strong metal,
and it may he fabricated from steel tubing or bar stock. Although in general
the grinding
ring 200 may be of any size, it is preferably less than about 100 mm in
diameter and even
more preferably less than about 50 mm in diameter. Its thickness (radially) is
substantially
less than its radius, e.g., by a ratio of 1:4 or smaller. The ring shape, as
opposed to a disk
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shape as used in more conventional grinding wheel designs, produces a much
lighter
grinding wheel 36 which can reduce the effects of wheel imbalance,
eccentricity, and
non-planarity. Reducing such effects can contribute to a smoother finish on a
skate blade
and a higher performance skate sharpening.
[0136] As shown,
both the arbor 212 and hub 202 have shaped outer edges
which mate with respective edges of the grinding ring 200. The mating between
the arbor
212 and ring 200 is a sliding contact mating that permits mounting and
dismounting of
the grinding wheel 36 while also providing for heat transfer between the
grinding ring
200 and the arbor 212. This relatively tight fit is also responsible for the
centering of the
grinding wheel. The heat transfer helps dissipate frictional heat generated in
the grinding
ring 200 as it rotates against a skate blade in operation. Specifically this
mating is
between a portion of an inner annular surface of the grinding ring 200 and an
annular
outer rim of the arbor 212. Both the hub 202 and arbor 212 have notches or
shoulders on
which respective portions of the grinding ring 200 rest. Thus the shoulder
portion of the
hub 202 extends only partway into the grinding ring 200, so that a remaining
part of the
grinding ring 200 extends beyond the arbor-facing end of the hub 202 and mates
with the
shoulder portion of the arbor 212.
[0137] The arbor
212 may include vanes or other features to increase its
surface area and/or enhance air flow for a desired cooling effect, further
promoting heat
dissipation and helping to maintain a desired operating temperature of the
grinding ring
200 in operation.
[0138] One
important feature of the grinding ring 200 is its relatively small
size, as compared to conventional grinding wheels which may be several inches
in
diameter for example. Both the small size of the ring (outer diameter) as well
as its ring
geometry (in contrast to disk geometry of conventional grinding wheels)
contribute to
advantages as well as challenges. Advantages include low cost and ease of
manufacture,
so that it can be easily and inexpensively replaced to maintain high-quality
sharpening
operation. The size and geometry also reduce any contribution of the grinding
ring 200 to
imbalance and related mechanical imperfections of operation. Balance and
related
operational characteristics are more heavily influenced by the arbor 212,
which is
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preferably precision-formed and precision-mounted. One challenge of the
geometry and
size of the grinding ring 200 is heat removal, and this is addressed in part
by the heat-
conducting mating with the arbor 212 and heat-dissipating features of the
arbor 212.
[0139] The
identification tag 204 has a unique identifier such as a
manufacturer's serial number, and when packaged with a grinding wheel 36 into
an
assembly serves to uniquely identify that assembly including the constituent
grinding
wheel 36. The identification tag 204 also includes memory capable of
persistently storing
data items, used for any of a variety of functions such as described further
below. The
identification tag preferably employs a security mechanism to protect itself
against
tampering and improper use, including improper manipulation of the contents of
the
memory. Memory protected in such a manner may be referred to as "secure
memory".
The serial number should be a read-only value, while the memory is preferably
both
readable and writeable. As described below, a separate transceiver in the
system 10 is
capable of exchanging communication signals with the tag 204 for reading and
writing
data. In one embodiment, so-called "RFID" or radio frequency identification
techniques
may be employed. Using RFID, the identification tag 204 is read from and
written to
using radio-frequency electromagnetic waves by an RFID transceiver contained
in the
sharpening system 10 (described more below). Other types of implementations
are
possible, including optically interrogated tags and contact-based tags such as
an iButton
device.
[0140] For
security, the identification tag 204 may use an access code that is
read by the control unit 32 and validated. The access code can be generated by
a
cryptographic hash function or other encryption algorithm that takes as input
the serial
number of the identification tag 204 and a confidential hash key. Using the
serial number
ensures that the access code created is uniquely paired with a specific
identification tag
204. This uniqueness can help reduce or eliminate the likelihood of misuse
that is
attempted by copying an access code from one identification tag 204 to
another. When the
serial number of the other identification tag 204 is encrypted, the result
will not match the
copied access code, and appropriate action can be taken such as reducing or
eliminating
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the likelihood of use of the grinding wheel 36 that contains the apparently
fraudulent
identification tag 204.
[0141] Figure 10
shows the sharpener 10 having the carriage 70 located in a
"home" position at the far right of the sharpener 10. The right end wall 52 is
cut away in
this view in order to show pertinent detail. Attached to the right wall 52 is
a housing 220
in which an electronic sensor module 222 is mounted. The sensor module 222 is
connected by cabling (not shown) to the controller 32 (Figure 6). In this
position the
grinding wheel 36 is adjacent to an inner side of the housing 220 and
vertically centered
on the housing 220 by action of a shoulder member 224 of the housing 220.
Additional
details of this arrangement are described below.
[0142] With
reference now to Figure 37, another configuration of a housing
1220 and sensor module 1222 is illustrated. As illustrated, the sensor module
1222 is
contained within a portion of the housing 1220. In one configuration, the
sensor module
1222 includes an RFID antenna or the like. Any type of communications antenna
may be
used that will facilitate communication between the skate sharpener 1010 and
the
grinding wheel 1036. In some configurations, the antenna is circular in shape
and
mounted to a circuit board. The circular shape for the RFID antenna has been
found to
increase the likelihood of consistent communication between the skate
sharpener 1010
and the grinding wheel 1036.
[0143] Other shapes
for the antenna and other locations are possible. For
example, the antenna could be located behind the grinding wheel 1036 when the
grinding
wheel 1036 is in the home position such that a user would see the grinding
wheel 1036
and the grinding wheel would obscure at least a portion of the antenna or the
housing
1220 containing the antenna or the like. In some configurations, the sensor
module 1222
could be positioned in a different location within the skate sharpener 1010.
For example,
the sensor module 1222 could be positioned at the opposite end of the
sharpening pass or
at another location along the sharpening pass. In some configurations, the
sensor module
1222 could be positioned between the two ends of the sharpening pass. In some
configurations, the sensor module 1222 could be positioned within a region
bounded by
the ends of the jaws of the clamps such that any time the grinding wheel 1036
made a full
28
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sharpening pass, the grinding wheel 1036 would pass through a region
containing the
sensor module 1222 (even if the grinding wheel 1036 did not move all the way
to the
home position).
[0144] In the
illustrated configuration, the circular shape of the antenna
provides a central area of the circuit board that can be removed without
adversely
impacting communication performance. The housing 1220 that encloses the sensor
module 1222 also can include an opening 1223. Because the home position for a
grinding wheel 1036 in the currently configuration is within a region
including the
housing 1220 (e.g., the read/write region), the grinding wheel 1036, when in
the home
position, would generally be obscured by the housing 1220. As shown in Figure
37, the
opening 1223 advantageously enables a user to view the grinding wheel 1036
without
turning on the sharpening system 1010. As such, the user is able to visually
inspect the
grinding wheel and, based upon the appearance of the installed grinding wheel
1036,
determine the type/style/hollow of the grinding wheel 1036 presently
installed. In some
configurations, rather than having an opening, the portion of the housing 1220
containing
the sensor module 1222 could be small enough in proportion that at least an
identification
portion of the grinding wheel 1036 would be exposed beyond the housing 1220.
[0145] While the
illustrated opening 1223 of the housing 1220 is concentric
with the grinding wheel 1036 in the home position, the opening 1223 could have
other
configurations keeping in mind a desire to view at least a portion of the
grinding wheel
1023 through the opening 1223. For example, the opening 1223 could be smaller
but
overlap a portion of the grinding wheel 1036 such that the opening 1223
provides a user
the ability to determine the variety of grinding wheel 1036 installed. In some
configurations, the opening 1223 is a window and has a covering such as a
light
transmissive or light transparent covering. In the illustrated configuration,
however, the
opening 1223 is not covered and allows physical access to the grinding wheel
1036.
[0146] As mentioned
above, the wheel 36 includes an identification tag 204
on which various data may be stored for a variety of purposes. In the
illustrated
embodiment this tag employs a wireless communication technique such as Radio
Frequency Identification (RFID) communications. The sensor module 222 includes
an
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RFID antenna (not shown) which becomes registered or aligned with the
identification
tag 204 when the grinding wheel 36 is in the illustrated home position, so
that the tag 204
may be read from and written to using RFID communications. Generally the RFID
antenna has one or more loops of conductive material such as wire or metal
etch, with the
loops having a circular or other shape (e.g., rectangular). The MD
communications may
operate on any of a number of frequencies. Frequencies in common use include
133 kHz
(Low Frequency or LF), 13.56 MHz (High Frequency or HF), and 900 MHz (Ultra
High
Frequency or iJIIF).
[0147] In the
illustrated embodiment the identification tag 204 is within the
circumference of the circular RFID antenna of the sensor module 222, e.g.,
concentric
with the antenna, during the reading and writing of data from/to the tag 204
as part of
operation. By this arrangement the identification tag 204 can be read from and
written to
even when the grinding wheel 36 is rotating at full speed, which may be
between 1000
and 25000 RPM. In some configurations, the tag 204 can be read from and
written to
when rotating at speeds between 700 RPM and 5000 RPM. In some configurations,
the
tag 204 can be read from and written to when rotating at speeds between 1000
RPM and
4000 RPM. Reading and writing at full rotational speed has a distinct
advantage of
allowing the sharpener 10 to sharpen more quickly, because it is not necessary
to
slow/stop wheel rotation and then bring rotation back up to speed for each
read/write
operation. As described more below, in one embodiment reading and writing
occurs once
during each 2-pass cycle, so the time savings is proportional to the number of
cycles in a
sharpening operation. Additionally, reading and writing at full rotational
speed can
discourage any tampering with the grinding wheel 36, because it is always
moving during
any attempted authentication or reading/writing process. In some embodiments
it may be
advantageous to maintain rotation but at a reduced rotational speed to improve
the
read/write communications with the tag 204.
[0148] Figure 11 is
a view from inside the sharpener 10 toward the front,
showing the inside- facing part of the housing 220 and other details. As
shown, the
shoulder member 224 has a sloped edge 226 and horizontal edge 228. When the
grinding
wheel 36 is returning to the home position, moving right-to-left in Figure 11,
it initially is
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at its vertical limit position as indicated in phantom. The spindle 62
encounters the sloped
edge 226 and follows it downward, then rides along the horizontal edge 228.
This motion
of the spindle 62 brings the wheel 36 into a desired vertical position with
respect to the
antenna within the housing 220, e.g., aligning the center of the wheel 36 with
the center
of the antenna. This alignment generally maximizes the RF coupling between the
antenna
and the tag 204, resulting in robust and accurate transfer of RF signals there
between.
[0149] Figure 12
shows the rear face of the arbor 212. It is a unitary
component including a set of rearward-facing projections or "vanes" 230, each
extending
generally radially with slight curvature as shown. With this configuration the
arbor 212
creates airflow in the vicinity of the arbor 212 and grinding ring 200,
increasing
convective heat dissipation from these components over an alternative lacking
this
feature. It will be appreciated that any of a variety of specific vane
configurations may be
employed, including non-curved vanes.
Grinding Wheel Vertical Travel Stop Adjustment
[0150] Figure 13
shows the front of the carriage assembly 70. The motor arm
78 is an oblong member mounted for rotation on a spindle axle 240 at the left
side of the
carriage 70. A Y- adjustment knob 242 is mounted on a separate Y-adjustment
axle
below the spindle axle 240. A height adjustment mechanism includes a rotating
adjustment member 244 and a bracket 246 extending downward from the motor arm
78
and having a limit peg 248. The adjustment member 244 includes a user handle
250 and a
pointer feature 252 having a terminus at an array of numbers arranged on the
carriage 70.
Its lower edge is scalloped by a series of faces having successively
increasing distances
from the center of rotation (proceeding clockwise along the edge).
[0151] As the
adjustment member 244 is turned, it presents different faces of
the scalloped lower edge at a rest position of the limit peg 248. When the
grinding wheel
36 is clear of the skate blade and the motor arm 78 rotates upward under the
action of the
spring 84, the upward travel is limited by the limit peg 248 encountering a
face of the
lower edge of the adjustment member 244. The different faces of the adjustment
member
244 are at different radii from the center of rotation of the adjustment
member 244,
thereby establishing different vertical locations for this rest position of
the limit peg 248.
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[0152] In
operation, a user rotates the adjustment member 244 to set a
maximum vertical position of the grinding wheel 36. The purpose of this
adjustment is to
set a vertical travel limit of the grinding wheel 36 when it comes off the
edge of the skate
blade. This feature helps tailor operation depending on the type of skate
being sharpened.
Regular ice hockey skates have rounded upturns at each end of the skate blade
(e.g. toe or
heel), and it is desired that the grinding wheel 36 move upward to follow the
upturns.
This can be accomplished by having a high maximum vertical position. The
blades on so-
called "goalie skates" are flatter and it is typically desired that the
grinding wheel 36 not
move as far upward as it leaves the end of the blade, but rather come off
relatively
straight. This can be accomplished by adjusting the height limit using the
adjustment
member 244 to set a lower maximum vertical position.
[0153] In Figure
13, the grinding wheel 36 is shown in a downward position
such as it occupies when riding along a skate blade, so the limit peg 248 is
well away
from the adjustment member 244. It will be appreciated that upward rotation of
the motor
arm 78, such as occurs when the grinding wheel 36 moves away from the skate
blade,
rotates the bracket 246 upward so that the limit peg 248 encounters the lower
edge of the
adjustment member 244.
[0154] Figure 14 is
a view from the left side of the sharpener 10, with the near
end wall 52 partially cut away. This view illustrates several features related
in some
manner to the compactness of the grinding wheel 36, i.e., its smaller diameter
relative to
that of the grinding wheel motor 80 (Figure 4). When conventional larger
grinding wheels
are used, there is inherently greater vertical space within which other
mechanical
components may be mounted, such as the grinding wheel motor, clamping jaws for
the
skate blade, etc. Using the compact grinding wheel 36 enables a corresponding
compactness in the overall skate sharpener 10, which is generally advantageous
but also
requires that more attention be paid to the design and organization of other
mechanical
features.
[0155] One feature
visible in Figure 14 is the height difference between the
rear shelf 56 and the lower front platform 22 of the chassis 14. The relative
height of the
shelf 56 provides clearance for the carriage assembly 72 and the components it
carries,
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including the grinding wheel motor 80 with its vertical movement on the motor
arm 78
(see Figure 4). The lower platform 22 is closer to the grinding wheel 36. The
jaws 90 are
located below the platform portion 22, even closer to the grinding wheel 36 to
permit the
skate blade to be retained at a sufficiently low position that it can be
contacted by the
grinding wheel 36 in operation. The above-described protective function of the
jaw guard
100 can also be appreciated in this view ¨ the spacing between this component
and the
spindle 82 is smaller than the spacing between the grinding wheel 36 and the
jaws 90.
[0156] Another
pertinent feature relates to a Y-adjustment mechanism
permitting fine adjustment of the position of the grinding wheel 36 to align
it with a
retained skate blade in the X-Z plane (which is perpendicular to the page of
Figure 14).
The grinding wheel 36 is mechanically coupled to the carriage 70 by a series
of
components including the spindle 82, the grinding wheel motor 80, and the
motor arm 78,
which is mounted to a spindle 251 having a spindle axle 240 mechanically fixed
to the
carriage 70. The spindle 251 includes an interior mechanism causing fine
translational
movement (horizontally in Figure 14) in response to rotation of a spindle gear
253. In
some embodiments, the spindle 251 is located above a nominal position of the
grinding
wheel 36, creating a desired arc of movement of the motor arm 78 and direction
of force
between the grinding wheel 36 and the skate blade. In order to actuate the Y-
adjust
mechanism of the spindle 251, an adjustment axle 254 on which the adjustment
knob 242
is mounted is located below the spindle 251 and has a gear 256 engaging the
spindle gear
253. This lower position enables a user to reach into the unit (from the front
opening
which is to the right in Figure 14) and rotate the adjustment knob 242 with
their fingers,
clearing the underside of the front platform portion 22 of the chassis 14.
[0157] Figure 14
also shows the above-mentioned carriage motor 260 that
drives the pinion gear 87 in engagement with the rack 120.
Use of Identification Tag 204
[0158] The grinding
wheel 36 utilizes the identification tag 204 to carry
important information and provide it to the control unit 32 of the sharpener
10. The
information carried by the tag 204 can be used to improve sharpening operation
and
reduce costs associated with the skate sharpener 10.
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[0159] Accurate and
repeatable skate sharpening is obtained when the
grinding wheel 36 is in good condition (e.g. running true, not excessively
worn, not
damaged). One of the limitations of existing sharpeners is that there is no
indicator for the
user that alerts them when the grinding wheel is not in good condition.
Generally the user
must make a judgment call on when to retire a grinding wheel. r[his may occur,
for
example, in response to a bad skating experience with skates that were
sharpened with a
grinding wheel that is no longer in good condition.
[0160] The
disclosed sharpener 10 can use the data-carrying ability of the
grinding wheel 36 to track usage, and employ the usage information in some way
to
promote delivery of consistent high quality sharpening. Generally this will
involve
comparing actual usage to a usage limit that has been predetermined as a
dividing point
between high quality sharpening and unacceptably low quality sharpening. When
the
usage limit is reached, some action is taken. For example, the control unit 32
may provide
an indication to a user via the user interface display panel 34. It may also
reduce or
eliminate the likelihood of further use of the grinding wheel 36, i.e.,
refrain from
performing any passes with a wheel whose usage has reached the limit, even if
such
continued use has been requested by a user.
[0161] In one
embodiment, the above usage tracking may be realized by
initially loading the usage limit value onto the tag 204 and then subtracting
or "debiting"
the stored value as the grinding wheel 36 is used. The usage limit may be
deemed to have
been reached when the stored value reaches a predefined number such as zero.
Generally
the usage tracking and usage limit may be specified in any of a variety of
ways, including
a count of passes or cycles as has been mentioned, or alternatively by
counting operating
time (tracking the operating time for each sharpening and accumulating the
time values
over a period of successive sharpenings). If the usage limit value is
specified as a
maximum number of passes, then the value is decremented by two for each 2-pass
cycle
of the grinding wheel 36 over a skate blade during sharpening. In one
embodiment, this
decrementing can take place once each cycle, with the grinding wheel 36
passing through
the home position (Figure 8) to enable the required RFID communications. In
another
embodiment, the updating may occur only once for a multi-pass sharpening
operation.
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For example, once a number of passes has been specified (either by default or
by actual
user selection), the number of passes may be updated by the system immediately
after the
machine reads the tag 204 and just before the carriage motor 260 begins
rotating. If the
stored value were updated less frequently or at a different time, there may be
more
opportunity for a user to somehow "trick" the sharpener 10 into using a
grinding wheel 36
longer than its useful life, which would jeopardize the quality of the skate
sharpening.
[0162] A specific
example is now provided for illustration. It is assumed that
the useful lifetime of a grinding wheel 36 is on the order of 160 passes. This
translates to
approximately 10 sessions of sharpening a pair of skates if an average of 4
cycles (8
passes) is used per skate (8 * 2 * 10 = 160).
[0163] In a given
embodiment, usage may be tracked in units of passes,
cycles, blades sharpened (assuming some fixed or limited number of passes per
blade),
time, or some other scheme. The UI display 34 may be used to display remaining
usable
life for a grinding wheel 36 to the user.
[0164] For example,
it may be displayed as a fraction or percentage, or as
more general ranges which could be indicated by colored indicators, for
example ¨ e.g.,
green for high remaining lifetime, white or other neutral color for
intermediate, and red
for low remaining lifetime. In one embodiment a linear array of indicators may
be used,
and indicators successively extinguished from one end as usage increases, and
the end-of-
life indicated by no indicators being lit.
[0165] Since there
will be user-to-user variability in how many passes are
done for a skate sharpening, the system may alert a user when the number of
cycles
needed to complete a sharpening exceed the number of cycles of remaining life
of the
grinding wheel 36. The alert may be provided, for example, by dimming or
flashing a set
of indicators, and/or by stopping a sharpening that is in progress or reducing
or
eliminating the likelihood of a new sharpening from beginning. Generally, it
is desired
that the display technique enable a user to accurately plan for use and avoid
running out
of usable grinding wheel lifetime in the middle of a sharpening
[0166] Beyond the
usage tracking information, the tag 204 may also be used
to carry system setup parameters that the control unit 32 can read and then
apply to
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operation. This programming-type approach can enable a single sharpener 10
having a
generalized design to be used in a wide variety of ways. For example, the tag
204 may
contain parameters for the rotational speed of the grinding wheel motor 80;
the speed of
translation of the carriage assembly 70 across the skate blade; and the
magnitude of a
normal grinding force (i.e., the force applied by the grinding wheel 36 in a
direction
normal to the bottom face of the skate blade 40). Employing customizable
settings in this
manner can support variability in the materials, diameters, and grits used for
different
grinding wheels 36. Larger wheel diameters for different skates, or different
grits for
different skate steels or surface finishes, will generally require different
system settings
(grinding wheel RPM and translation speed) for optimized use. In operation,
the control
unit 32 can read the parameters from the tag 204 and then apply the parameters
prior to
beginning a sharpening operation, such as by programming the appropriate
controllers
132 (Figure 6). This programmability may also promote compatibility as designs
of the
grinding wheels 36 evolve over time. For example, if an innovation in grinding
wheel
abrasives happens in 5 years and this requires different system settings, the
wheels
produced in 5 years will store corresponding values of operating parameters to
enable
existing sharpener systems 10 to properly adjust themselves to produce an
optimal
sharpening. Not only can these parameters be used to program the machine, the
parameters can define an evolution of parameters over the life of the wheel.
For example,
a grinding wheel may exhibit a change in abrasiveness, which would result in a
change in
material removal rate over time, which can be compensated for by altering the
rotation
speed of the wheel motor, the translation speed, and/or the force applied, for
example but
without limitation. Any and all of these parameters, among others, could be
defined and
could vary over the recorded usage life of the grinding wheel. In one
embodiment, the
rotation speed dictated by the grinding wheel is defined by parameters stored
on the
wheel that define a polynomial curve for rotation speed as a function of the
number of
cycles that the grinding wheel has been used.
[0167] The
identification tag 204 may also store user-specific settings to be
used for sharpening operations, such as a default number of passes for a skate
sharpening.
The control unit 32 can read such values and then use them unless they are
overridden by
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a specific current selection by the user. One user may sharpen relatively
frequently and
typically use a small number of passes, such as two, while another user may
sharpen less
frequently and typically use a larger number of passes, such as eight. The
user interface
preferably would enable a user to modify or update any such persistently
stored values.
Saving user-specific values on the grinding wheel 36 also enhances
"portability" of the
customization. A user can carry their own grinding wheel 36 and mount it for
use in
different sharpener systems 10 at different locations while still obtaining
the same user-
specific operation. For example, an organization such as a hockey club or rink
operator
can provide access to a sharpener system 10 and allow users to swap grinding
wheels 36,
so that each user receives a desired user-specific experience.
[0168] The
sharpener system 10 may also have features for defeating
counterfeiting or certain tampering with tags 204. For example, it might
record the unique
tag identifiers (e.g., tag serial numbers) for every tag 204 that has been
used over some
interval on that sharpener, as well as recording the number of passes that
were last seen
on the tag 204. If there is ever a time when a sharpener 10 sees a grinding
wheel 36 that it
has seen before but having remaining pass count greater than the number of
remaining
passes last seen on that wheel, the sharpener 10 could deem the grinding wheel
36 to be a
counterfeit or tampered with and prevent its use. This might be done to insure
that only
grinding wheels 36 of sufficient quality are used, to obtain good sharpening
results and
avoid any unsafe conditions that could occur by using a defective or inferior
grinding
wheel 36. The system 10 may store the most recent passes remaining count as
individual
numbers or as percentages similar to the way the system displays the grinding
wheel
remaining life to the user.
[0169] Yet another
possibility is for the tag 204 to store system fault data, i.e.,
data describing fault conditions that have occurred during a sharpening
operation. This
can help users interact with technical service to diagnose problems they may
be having
with their machine. A manufacturer or service organization might request that
the user
send a grinding wheel 36 to that organization for review. The grinding wheel
is smaller
and thus far cheaper and convenient to send than is the entire system 10. At
the
manufacturer or service organization, technicians can read fault data such as
fault codes
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from the wheel 36. In another embodiment, the identification tag 204 may be
compatible
with readers such as near-field communications (NFC) readers such as used on
smart
phones and similar small computing devices. When the user experiences a system
fault,
the user can remove the grinding wheel 36 and place it near the computing
device. The
device might immediately launch an application or navigate to a particular web
site to
provide information to the user about the particular fault that is identified
by the fault data
stored on the tag 204. Another use for this type of interface is for
repurchasing grinding
wheels 36. The application or website launched by the device may provide
product
ordering functionality, enabling a user to easily obtain replacement grinding
wheels 36 as
existing grinding wheels are used up. In some configurations, the application
or website,
for example, may provide a tool for reading a grinding wheel life indicator
and, in some
configurations, for providing the ability to reorder grinding wheels. Such
configurations
can simplify the ordering process for operations or individuals with a large
number of
rings to track, monitor and replace, for example but without limitation.
[0170] Figure 15
provides a high-level description of system operation with
respect to the identification tag 204. At 270, the system 10 engages in
communication
with the identification tag 204 which is attached to a grinding wheel 36
mounted in the
sharpening system 10. As described above, the identification tag 204 has
secure memory
including a usage location for persistently and securely storing a usage
tracking value.
The communication both reads from and writes to the usage location.
[0171] At 272, the
system 10 tracks usage of the grinding wheel 36 for
sharpening operations and writes updated usage tracking values to the usage
location as
the grinding wheel 36 is used for the sharpening operations. Usage may be
tracked by
counting passes, for example, in which case it may be convenient for the usage
tracking
value to be expressed as a pass count. The usage value may directly indicate
an amount of
usage that has occurred, e.g., as an increasing count of passes, or it may be
directly
indicate an amount of usage remaining, e.g., as a decreasing count of passes.
[0172] At 274, the
system 10 reads a current usage tracking value from the
usage location and selectively enables and disables sharpening depending on
whether a
usage limit has been reached, as indicated by a relationship between the
current usage
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tracking value and a predetermined usage limit value. When a decreasing or
decremented
usage value is used to indicate an amount of usage remaining, then the
predetermined
usage limit value can be used as the starting usage value, and the usage limit
is reached
when the usage value is decremented to zero. As indicated above, the system 10
also can
read usage parameters (e.g., rotational speed, translation speed, etc.) for
use during
operation. Furthermore, one or more of those usage parameters may vary over
the life of
the grinding wheel such that, as the grinding wheel experiences wear over
time, the
operation of the system may be adjusted accordingly.
[0173] Figure 16 is
a section view of the platform area 22 of chassis 14. The
clamp paddle 26 and left slot cover 28 (Figure 1) are shown, as well as
various
components of the blade clamping mechanism described above with reference to
Figure
5,
Slot Covers
[0174] Referring
first to the slot cover 28, a button 27 is mounted for rocking
on a horizontal axis and has a downward-extending rack 300 at the rear. The
rack 300
engages a pawl 302 attached to the arch (rounded projections) 64. A spring
(not shown)
biases the button 27 so that its top is co-planar with the top of the slot
cover 28 and the
rack 300 engages the pawl 302, locking the slot cover 28 in place. In use, a
user depresses
a front part of the button 27 (see Figure 1), lifting the rack 300 and
enabling the slot cover
28 to slide left and right along the arch 64. The left slot cover 28 travels
between a far left
position and a more rightward position in which it covers the left end of the
slot 24. A
limit for the far left position is established by the rightmost wall of the
slot cover 28
hitting a rightward wall or face of the arch 64 adjacent the platform 22. A
limit for the
rightward position is established by the left wall of the slot cover 28
hitting the pawl 302.
There is a similar but mirrored arrangement for the right slot cover 28. While
the slot
covers 28 are designed for manual operation to move to a closed position, it
also is
possible to configure the skate sharpener such that the slot covers are biased
to a close
position and are moved apart for insertion of a skate blade. In some such
configurations,
a mechanical member, such as a lever or the like, can be used to hold the slot
covers in
the open position until a skate or skate blade is properly positioned. The
slot covers are
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considered to be in an open position when positioned away from the skate blade
or skate
blade holder. The open position of the slot covers can also be referred to as
a non-
occluding position, and the closed position of the slot covers can be referred
to as an
occluding position. Additional details of the slot cover 28 are given below.
Skate Blade Clamping Details
[0175] Referring
next to the blade clamping mechanism, as shown in Figure
16, a pin 304 secures a vertex portion of the U-shaped pull rod fork 92to the
pull rod 102.
The pull rod 102 extends through the clamp cylinder 94, terminating at a
piston head 306.
The pull rod 102 is disposed within bushings 307, 308. A spring 310 is
disposed between
one end of the body of the clamp cylinder 94 and an external retaining ring
312 on the
pull rod 102. The spring 310 biases the pull rod 102 to the left in Figure 16
such that,
unless urged away from the end of the body of the clamp cylinder 94 closest to
the handle
26, the piston head 306 is seated against that end of the body of the clamp
cylinder 94.
[0176] When the
clamp paddle 26 is in the position shown, the cam 96
presents a lower-radius face to the piston 306, and the spring 310 urges the
pull rod 102
to a maximum retracted position, to the left in Figure 16. The pull rod fork
92 is under
tension and pulls the clamp jaws 90 (Figure 5) in a closed position. The
illustrated closed
position, without a skate blade present, is not fully closed (i.e., clamp jaws
90 in contact
with each other) yet the closed position, without a skate blade present, is
not a position in
which the clamp jaws 90 are spaced apart enough to receive a skate blade. If a
skate
blade is present then the clamp jaws 90 clamp the skate blade into place with
a force
geometrically related to the force created by the spring 310. This arrangement
is referred
to as a biasing mechanism and the force as a bias force.
[0177] A user opens
the clamp jaws 90 by pushing downward on an outer part
of the paddle 26, rotating it counterclockwise in the view of Figure 16. The
cam 96 has
increasing radius in this direction and pushes the piston head 306 rightward
against the
force of the spring 310. This action releases the clamping force between the
jaws 90 and
skate blade if present, and pushes the pull rod fork 92 rightward pushing the
jaws 90
apart. The jaws are fully open when a maximum- radius part of the cam 96 is
contacting
the piston head 306. This maximum-radius location can generally be anywhere in
a range
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of about 10 degrees to 90 degrees from the closed position of Figure 16. For
smooth
operation and good mechanical advantage it may preferably be somewhere in the
smaller
range of 40 degrees to 75 degrees. In one embodiment it is located at 60
degrees. As
mentioned above, a configuration providing a detent action may be used. For
example,
the cam 96 may have a slightly flattened area at maximum-radius location for a
slight
detent action.
[0178] Figures 17
through 21 show details of the jaws 90 including
connections to respective ends of the pull rod fork 92. Figures 17 and 18 show
plan views
of the bottoms of the rear and front jaws 90-R, 90-F respectively. Figures 19
and 20 show
sections through a guide slot 104 and guide block 106 of the rear jaw 90-R,
and Figure
21 shows a section through a guide slot 104 and guide block 107 of the front
jaw 90-F.
[0179] Figure 17
shows the use of two guide blocks 106 at respective endmost
slots 104 for the rear jaw 90-R. The slots 104 are oriented at approximately
30 degrees
with respect to the long axis of the jaws 90 (X direction). In response to
force exerted by
the pull rod fork 92, the jaw 90- R slides along the guide blocks 106. When
opening, the
rear jaw 90-R moves upward and to the left in the view of Figure 17, and when
closing it
moves in the opposite direction. The rear jaw 90-R maintains a fixed
orientation
substantially along the X axis. It establishes the orientation of the clamped
skate blade,
which should be highly co-planar with the X-Z plane of movement of the
grinding wheel
36.
[0180] As shown in
Figure 18, the front jaw 90-F has a generally symmetrical
configuration with respect to the rear jaw 90-R, and it moves symmetrically as
well, i.e.,
downward and to the left when opening in the view of Figure 18. However, the
front jaw
90-F is secured with only one guide block 107, located in the center guide
slot 104. As
described more below, the guide block 107 is mounted in a manner pefinitting
slight
pivoting, while the guide blocks 106 for rear jaw 90-R are not. Thus, the
front jaw 90-F
also rotates slightly about the Z-direction axis of the single central guide
block 107. This
enables the front jaw 90-F to conform its orientation to that of the rear jaw
90-R when a
skate blade is clamped between them. It will be appreciated that this
configuration avoids
issues that could occur if the front jaw 90-F had an orientation that was
fixed but slightly
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different from that of the rear jaw 90-R due to normal mechanical tolerances.
These
issues include mechanical binding, uneven force across faces of the jaws
(higher at one
end than at the other), as well as inaccuracy in the orientation of the skate
blade,
adversely affecting sharpening quality. The illustrated configuration avoids
these issues
by allowing the rear jaw 90-R to serve as a mechanical reference and the front
jaw 90-F to
conform itself to that reference.
[0181] Figures 19
through 21 illustrate certain functionality provided by the
configuration of a guide slot 104 (i.e., of its surrounding walls) and the
guide blocks 106,
107. As shown, the jaws 90 are spaced from the platform 22 by respective
spacer blocks
343 which are rigidly secured to the underside of the platform 22. The jaws 90
and guide
blocks 106, 107 have a configuration that provides for spacing the jaws 90
slightly from
the respective spacer blocks 343, enabling the jaws 90 to slide easily between
open and
closed positions. The configuration also provides for closing this spacing
when the jaws
90 are brought into the closed position, so that they rest flush against the
spacer blocks
343. This action makes the jaw positioning precise and accurate. It also
reduces or
eliminates the likelihood of the jaws 90 tilting about their longitudinal
axes, which would
tend to occur if the space were not closed up as the jaws 90 are tightened
against the skate
blade 40. Maintaining a predictable flat orientation of the jaws 90 provides
for greater
accuracy in the positioning of the clamped skate blade 40.
[0182] Figures 19
and 20 show details for the rear jaw 90-R. The guide blocks
106 for the rear jaw 90-R are fastened to the spacer block 343 by bolts 338.
The jaw 90-R
and guide block 106 have respective sloped or angled surfaces 340, 342
contacting each
other. The jaw surface 340 is one side wall of the guide slot 104 (Figure 17)
in which the
guide block 106 is located. Figure 19 is a section view showing these surfaces
340, 342 as
lines at the intersection with the Y-Z plane of the paper. Referring back to
Figure 17, the
surfaces 340, 342 are also angled in the direction of the guide slot 104,
which corresponds
to a plane through the paper of Figure 19, tilted about 30 degrees to the left
of X-direction
normal. In the view of Figure 19, the front of the jaw 90-R and skate blade 40
are at the
left. The jaw 90-R is pulled in the X direction out of the paper to be closed,
and pushed in
the opposite direction to be opened. The pulling and pushing cause
corresponding
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leftward (closing) and rightward (opening) motion by action of the angled
guide slots
104.
[0183] Figure 19
shows that the combination of the thickness of the rear jaw
90-R, the width of the guide slot 104, and the height and width of the guide
block 106 is
such that the top of the jaw 90-R is slightly spaced from the bottom of the
spacer block
343 in the illustrated position. This is a first condition in which the jaw 90-
R is slack, i.e.,
not exerting a clamping force. This could be either a fully or partially open
position. The
jaw 90-R rests relatively loosely on the guide block 106 and is able to slide
thereon
without interfering contact with the spacer block 343. There is a slight space
345 between
the jaw 90-R and guide block 106 as shown.
[0184] Figure 20 is
a similar view as Figure 19 but in a second condition in
which the rear jaw 90-R is pulled tightly by the pull rod fork 92 (Figure 5)
and exerting a
clamping force on the skate blade 40. As the jaw 90-R encounters the skate
blade 40 it
experiences a rightward force causing it to ride up the surface 342 of the
guide block 106
until the top of the jaw 90-R hits the bottom of the spacer block 343. This
movement
closes the space 345 and opens a separate space 347 on the other side of the
guide block
106. Because the surfaces 340, 342 have precisely the same slope, the jaw 90-R
automatically assumes a position in which its upper surface is flush against
the bottom
surface of the spacer block 343. As the motion ceases, the combined forces of
the pull rod
fork 92 and the skate blade 40 press and hold the jaw 90-R at this upward
position, tight
against the guide block 106. This action occurs consistently whenever the jaw
90-R is
closed, and thus the rear jaw 90-R and skate blade 40 are consistently
positioned.
[0185] The above
motion reverses when the jaws 90 are opened. As the rear
jaw 90-R is pushed in the X direction, clamping tension is released and it
slides
downward in the Z direction, closing the space 347 and returning to the
position of Figure
19 The configuration providing the space 347 in the closed position of Figure
20 also
provides for the slight looseness of the jaw 90-R that permits it to slide
easily when slack.
[0186] Figure 21 is
an analogous view to that of Figure 20 but for the front
jaw 90-F, which is secured via only one guide block 107 as described above.
The
configuration and operation are essentially the same as for the rear jaw 90-R
¨ the front
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jaw 90-F is pushed against the spacer block 343 and guide block 107 in the
same manner,
and has the same configuration providing for spaces 345 and 347. However, the
guide
block 107 is secured to the spacer block using a shoulder screw 346 in a
tightly toleranced
counter-bored hole of the guide block 107. The shoulder screw 346 and counter-
bored
hole of the guide block 107 are sized to create a slight gap 348, so that the
guide block
107 is not secured tightly to the spacer block 343. Thus, the guide block 107
is free to
rotate slightly about the Z-direction axis of the shoulder screw 346 to
provide the above-
described rotational compliance of the front jaw 90-F.
[0187] In the
illustrated embodiment as described above with reference to
Figures 19 through 21, the jaw closing direction (left or right) is
perpendicular to the
direction of the actuating force (out of the paper), and the slots 104 are
angled
accordingly to translate the actuating force to the clamping force. Also, the
actuating
force is a pulling force, essentially pulling each jaw 90 up the surface 342
of the guide
blocks 106, 107. It will be appreciated that in alternative embodiments other
configurations may be used, depending in part on the relative locations of the
jaws and
the force-generating actuator as well as the nature of the force as either
compressing or
tensioning the jaws. In particular, the slots 104 may be oriented at angles
other than 30
degrees. Also, in the illustrated embodiment the jaw 90 is slightly thinner
than the height
of the guide block 106, but this is not essential.
[0188] In the
illustrated embodiment the jaws 90 are urged against a lower or
bottom surface of the spacer blocks 343, which are fixedly secured to the
underside of the
platform 22 of the chassis 14. More generally the jaws 90 are urged against a
surface that
is in some manner referenced to the chassis 14, i.e., having a fixed position
with respect
to the chassis 14. In an alternative embodiment, the jaws 90 might be secured
directly to a
surface of the chassis 14 itself, such as the bottom surface.
[0189] With
reference now to Figure 42, a bottom view of another clamping
mechanism 1088 is shown. The illustrated clamping mechanism 1088 broadly
includes a
paddle 1026 that is removably connected to a cam member 1096. The cam member
1096
is mounted to a shaft 1097 (see Figure 44) to rotate relative to a horizontal
axis such that
a portion of the cam member 1096 can bear against a piston head 1306 (see
Figure 44) of
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a clamp piston that is contained within a clamp cylinder 1094. In some
configurations,
the cam member 1096 is pivotally or rotationally mounted to the clamp cylinder
1094
itself. A pull rod 1102 of the clamp piston extends beyond the clamp cylinder
1094 and
couples to a pull rod yoke 1103. The pull rod yoke 1103 is connected to a pair
of pull rod
legs 1092. The pull rod legs 1092 are connected to the jaws 1090.
[0190] With the
illustrated clamping mechanism 1088, the pull rod 1102 is
urged to the left in Figure 43 under the force of a biasing member that can be
positioned
within the clamp cylinder 1094. Any suitable biasing member can be used, such
as a
coiled compression spring, for example but without limitation. The pull rod
1102 forms a
portion of a piston that is predominantly positioned within the clamp cylinder
1094. The
cam member 1096, when rotated by pivoting the paddle 1026, bears against a
head of the
piston and forces the pull rod 1102 to the right against the biasing force of
the biasing
member. Rightward movement in Figure 43 of the pull rod 1102 is translated
through the
yoke 1103 and the pair of pull rod legs 1092 to the jaws 1090.
[0191] In the
illustrated configuration, the paddle 1026 is removable from the
cam member 1096. In some configurations, the paddle 1026 is designed to slide
off of
the cam member 1096 in a vertical direction. Thus, in such advantageous
configurations,
the paddle 1026 would be prone to separate from the cam member 1096 if a user
were to
attempt to lift the skate sharpener 1010 using the paddle 1026. By allowing
the paddle
1026 to separate in this manner, a risk of damage to the clamping mechanism
1088
caused by lifting from the paddle 1026 can be reduced or eliminated. in the
illustrated
configuration, as shown in Figure 44, the paddle 1026 can include a recess or
pocket that
receives the cam member 1096 and the paddle 1026 and the cam member 1096 can
have
interlocking features. Any suitable interlocking construction can be used. In
the
illustrated configuration, the paddle 1026 has a flexible finger 1025 while
the cam
member 1096 has an embossment 1099. The finger 1025 and the embossment 1099
can
be designed to snap-fit together such that an audible clip, snap or pop can be
head to
verify for the user that the paddle 1026 has been fully installed on the cam
member 1096.
In some configurations, the cam member 1096 can include a pocket that receives
at least a
portion of the paddle 1026. Other configurations also are possible keeping in
mind a
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desire to couple together the paddle 1026 and the cam member 1096 in a manner
that
allows the two components to be used together to operate the clamping
mechanism 1088.
For example, the paddle 1026 and the cam member 1096 can slide apart in a
horizontal
direction or other direction other than vertical. Such configurations will
not, however,
result in the added advantage of reducing or eliminating the likelihood of the
skate
sharpener 1010 being lifted by the paddle 1026. Furthermore, providing an
easily
removed and easily reconnectable paddle improves the portability,
transportability and
packing of the sharpener. In some configurations, the size of a box or
carrying case can
be reduced simply because the paddle is easily removed and reinstalled.
[0192] With
reference now to Figure 45, an enlarged bottom view of the jaws
1090F, 1090R is presented. The jaws 1090F, 1090R differ from the jaws 90F, 90R
shown in Figures 17 and 18 mainly in the manner in which the jaws 1090F, 1090R
are
secured for movement. As with the configuration of Figures 17 and 18, the jaws
1090F,
1090R maintain a structure by which one of the jaws 1090F is secured to pivot
about a
single location 1107 while the other of the jaws 1090R is secured in two
spaced apart
locations 1108. In the illustrated configuration, one of the locations 1107 is
disposed
between the other two locations 1108. In the illustrated configuration, the
locations 1107,
1108 form a triangle. In the illustrated configuration, the locations 1107,
1108 form a
triangle with the largest distance between the centers of the locations 1107,
1108 being
the distance between the centers of the locations 1108 on the same jaw 1090R.
In the
illustrated configuration, the location 1107 is offset toward the location
1108 on the right
in Figure 45 (i.e., the location 1107 is not equidistant from both of the
locations 1108).
Other configurations are possible.
[0193] As shown in
Figure 46, the locations 1108 can include a flanged
bearing 1110 or the like secured in position within a recess 1104. In some
configurations,
a shim can be positioned between the bearing 1110 and the spacer block 1343F,
1343R.
The bearing 1110 can be secured in positon using a button head socket cap
screw 1111, or
another other type of threaded fastener or the like. Similarly, at the pivot
location 1107 of
the front jaw 1090F, the location 1107 can include a bearing secured in
position with a
button head socket cap screw 1111, or another other type of threaded fastener
or the like.
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The use of bearings 1110 in place of the blocks used in Figures 17 and 18
improves the
life and performance of the jaws 1090F, 1090R. The bearings 1110 reduce
sliding
friction compared to the blocks used in Figures 17 and 18. The blocks, when
operating as
desired, would pull the jaws 90F, 90R tight against the spacer blocks 343. The
bearings
1111 do not cause the jaws 1090F, 1090R to be drawn up tight against the
spacer blocks
1343F, 1343R but the bearings 1111 provide consistent flush engagement between
the
jaws 1090F. 1090R and the skate blade, when present.
[0194] In addition,
to provide fine adjustment of the jaws 1090F, 1090R
during manufacture, the jaws 1090R, 1090R are secured in position relative to
the spacer
blocks 1343F, 1343R using fasteners 1338. These fasteners 1338 can be secured
to the
spacer blocks 1343F, 1343R. In some configurations, as shown in Figure 48, to
provide
adjustment to the orientations of the jaws 1090F, 1090R relative to each
other, one or
more of the fasteners 1338 can be secured in oblong openings formed within the
spacer
blocks. For example, the left opening in the forward spacer block 1343F, 1343R
in
Figure 45 can be elongated in the left to right direction while the two
openings adjacent to
the bearing locations 1108 in the rearward spacer block 1343F, 1343R in Figure
45 can
be elongated in the up to down direction. Through the use of the elongated
openings in
the spacer blocks 1343F, 1343R, the angular orientation of each of the jaws
can be
corrected or finely adjusted during manufacture or repair.
[0195] In some
configurations, one or both of the jaws 10901-,, 1090R can be
provided with one or more additional motion confining element. In the
configuration
illustrated in Figure 45, a dowel 1350 can project from the spacer block
1343F, 1343R
into a slotted opening 1352 formed in the forward jaw 1090F. Other
configurations are
possible keeping in mind a desire to control relative pivoting of the two jaws
1090F.
1090R to enable the jaws 1090F, 1090R the ability to abut an interposed skate
blade with
generally equal force being contributed by each end of the jaws 1090F, 1090R.
[0196] With
reference to Figures 45 and 47, the jaws 1090F, 1090R have a
stepped jaw configuration. In other words, a land portion 1360 is defined on
each of the
jaws 1090F. 1090R. The land portion 1360 results from the presence of a small
step from
a main body of the respective jaw 1090F, 1090R. The land portions 1360 can
include one
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or more aperture or opening 1362. The openings 1362 can be symmetrically
disposed
along the land portion 1360 in some configurations.
[0197] As shown in
Figures 45 and 47, the jaws 1090F, 1090R can be
provided with a removable jaw riser 1364. The jaw risers 1364 can be installed
on the
jaws 1090F, 1090R to elevate an abutment surface that will support a goalie
skate or
another skate (e.g., a smaller skate, such as a small child's skate) during a
sharpening
operation. By lifting the skate with the risers 1364, it is possible to take
into account
differences among varying skate types (e.g., skater v. goalie) while
maintaining the use of
a smaller diameter grinding wheel, the scoop bumper switches and the like. For
example,
in the case of a small skate, the boot/skate holder design may result in a
construction that
may not consistently register against the scoop bumper and use of the jaw
risers can
improve the consistency of registration against the scoop bumper.
[0198] The
illustrated jaw risers 1364 have a contoured upper surface 1366.
The contoured upper surface 1366 can include one or more indicators to help
guide a user
for placement of a finger or thumb during installation and/or removal.
Moreover, the
contoured surface provides a region of reduced cross-section that allows
increased flexure
in the region of the indicators.
[0199] In the
illustrated configuration, pins 1368 are disposed directly below
one or more of the contoured regions 1366. The pins 1368 are received within
the
openings 1362 formed on the land portions 1360 of the jaws 1090F. 1090R. The
pins
1368 can help guide the user to correct installation. The pins 1368 also can
reduce or
eliminate the likelihood of the jaw risers 1364 sliding laterally off of the
land portions
1360 when installed correctly.
[0200] The jaw
risers 1364 also include hooked ends 1370. The hooked ends
1370 enable the jaw risers 1364 to be secured to the jaws 1090F, 1090R. In
some
configurations, the hooked ends 1370 can be designed and configured to snap-
fit to the
land portions 1360 of the jaws 1090F, 1090R. Other configurations also are
possible.
[0201] With
reference to Figures 45 and 46, the illustrated configuration also
comprises a jaw guard 1380. The jaw guard 1380 can be sized and positioned to
reduce
or eliminate the likelihood of contact between the grinding wheel 1036 and the
jaws
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1090F, 1090R. In the event that the skate sharpener 1010 is operated without a
skate
being positioned within the jaws 1090F, 1090R, it would be possible for the
grinding
wheel 1036 to grind the bottom surface of the jaws 1090F, 1090R without the
presence of
the jaw guard 1380. The jaw guard 1380 contacts a portion of the skate
sharpener 1010
that moves along with the grinding wheel 1036. For example, in the
configuration
illustrated in Figure 49, the jaw guard 1380 is sized and positioned to
contact the spindle
1082 that connects to and rotates the grinding wheel 1036. As such, upon
translation of
the carriage assembly 1070 in the region of the jaws 1090F, 1090R without a
skate
present, the spindle 1082 will ride along the jaw guard 1380, which will urge
the spindle
1082 downward and maintain a clearance between any grinding wheel secured to
the
spindle 1082 and the bottom surface of the jaws 1090F, 1090R.
[0202] The
illustrated jaw guard 1380 is secured to the rear jaw 1090R. In
some configurations, the jaw guard 1380, when positioned within the skate
sharpener
1010, has an uppermost contact portion 1382 that is vertically higher than a
rotational
axis of the grinding wheel (i.e., which is coaxial with the spindle 1082 in
the illustrated
configuration) in its uppermost position and a lowermost contact portion 1384
that is
vertically lower than a lowermost portion of the jaws 1090F, 1090R.
Preferably, the
lowermost contact portion 1384 is a distance below the jaws 1090F, 1090R that
is
sufficient to ensure that the grinding wheel 1036 does not contact the bottom
of the jaws
1090F, 1090R. In this manner, the grinding wheel will be forced downward a
sufficient
distance to clear the bottom of the jaws 1090F, 1090R.
Slot Cover Details
[0203] Figure 22A
is a bottom view of a slot cover 28 and an arch 64 on
which it is captured. Figures 22B and 22C are additional views of the slot
cover 28 while
Figure 22D is a simplified view showing the slot cover 28 engaged with the
arch 64.
[0204] With
reference now to Figure 22A, the bottom of the button 27 is
visible, including the rack 300 that moves in and out of the page in this view
when the
button 27 is operated as described above. The slot cover 28 is retained on the
arch 64 by a
latch-like rail mechanism including inner edges 318 of the slot cover 18 that
fit within
corresponding elongated grooves on the upper surface of the arch 64 where the
central
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rounded portion 319 meets the lateral flat portions 321. The inner edges 318
act as
fingers that slide within the generally U-shaped channels defined by the
elongated
grooves on the upper surface of the arch 64. The connection between the slot
cover 28
and the arch 64 is best shown in Figure 22D.
[0205] In the
illustrated embodiment, the bumper 29 is attached to the body of
the slot cover 28 (at lower left corner in Figure 22A). The attachment is with
a pin or
similar fastener 320 that permits the bumper 29 to rotate about a generally
vertical
rotational axis. A face portion 322 contacts a skate blade holder in operation
as described
above (Figure 1 and related description). Another portion 324 extends to an
actuation
lever 326 of a limit switch 328. The bumper 29 is biased (counterclockwise in
this view)
by a spring 330. The limit switch 328 is wired to the controller 32 (Figure 6)
to enable the
controller 32 to sense its electrical state (open or closed). The wires are
omitted in Figure
22 for ease of illustration. In some configurations, however, the limit switch
328 is
connected to the controller 32 using thin flexible silicone wires (e.g., 26
AWG). Other
configurations also can be used.
[0206] In
operation, the limit switch 328 is electrically open by default. In
addition, the actuation lever 326 is held away from actuating the limit switch
328 by the
mechanical biasing action of the spring 330. When the face portion 322 of the
bumper 29
is depressed (e.g., brought into contact with a skate blade or skate blade
holder), the
bumper 29 rotates (clockwise in this view) and the arm 324 depresses the limit
switch
lever 326, causing the limit switch 328 to change from electrically open to
electrically
closed. If the cover moves even further into engagement with the skate or
skate blade
holder, the over-travel would be taken up by bending of the leg 324 that
engages the
switch 328.
[0207] When the
face portion 322 of the bumper 29 is no longer depressed
(e.g., the skate blade or skate blade holder is removed or the cover 28 is
moved away
from the skate blade or skate blade holder), the spring 330 acts to return the
bumper 29 to
the original position and the arm 324 stops depressing the limit switch lever
326, which
returns the limit switch 328 to the normally electrically open state.
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[0208] The state of
the limit switch 328 as open or closed is sensed by the
controller 32. In one embodiment, sharpening operation is permitted only when
the limit
switch 328 is sensed as electrically closed, which normally occurs when a
skate blade is
clamped in position and the slot covers 28 have been moved inward to contact
the skate
blade holder. In these operating positions the slot covers 28 cover the outer
ends of the
slot 24 that would otherwise be open. The operating position of the slot cover
28 can also
be referred to as an occluding position. In the operating position, the
position of the slot
covers 28 can reduce, limit, or eliminates the likelihood of the introduction
of any objects
through the outer ends of the slot 24, where such objects might harmfully
contact the
rotating grinding wheel 36 as it moves along the slot 24, during a sharpening
operation. If
the limit switch 328 of either slot cover 28 is sensed as open, which normally
occurs
when either a skate or skate blade holder is not present or both slot covers
28 have not
been moved inward to their operating positions, the controller 32 prevents
sharpening
operations, i.e., provides no electrical drive to the grinding wheel motor 80
and the
carriage motor 260. With these motors not rotating, it is safer to introduce
objects (such
as a skate blade during mounting, for example) into the slot 24. By using the
configuration described, a failure of the switch or of the switch actuating
mechanism
would result in the controller 32 detecting that the skate sharpener 10 is not
reading to
sharpen.
[0209] With
reference to Figure 22C, the face portion 322 of the bumper 29
incorporates a lighting feature 332. The lighting feature 332 can comprise a
light pipe
that is in optical communication with an LED or other light source. In some
configurations, the lighting feature 332 comprises an LED or other light
source that is
positioned adjacent to the bumper 29 and the bumper or at least a portion of
the bumper
29 can be formed of a translucent material with a painted mask on the front.
Any other
suitable lighting feature can be used. The lighting feature 332 is disposed on
or around
the face portion 322. In some configurations, the lighting feature 332 is
positioned such
that the lighting feature 332 illuminates an outline of the face portion 322
of the bumper
29.
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[0210] The lighting
feature 332 can be always on when the slot cover 28 is not
in contact with a skate blade or a skate blade holder. In other words, the
lighting feature
332 can direct the user's attention to the need to close the slot cover 28
prior to initiating
operation of the skate sharpener 10. When the slot cover 28 has been moved
into
engagement with the skate blade or skate blade holder, the lighting feature
332 is turned
off. If a user attempts to start a skate sharpening operation without closing
the slot covers
28, the lighting feature 332 will flash to direct the user's attention to the
need to close the
slot covers 28 and, as discussed directly above, the controller will not
initiate the skate
sharpening operation until the slot covers are moved into position in
engagement with the
skate blade or skate blade holder. In some configurations, the lighting
feature 332 is
turned off, or an intermittent flashing is started or stopped, when the slot
cover 28 has
been moved into engagement with the skate blade or skate blade holder. Any
other
suitable attention directing configurations can be used.
[0211] There are
various alternatives to the configuration described above. An
alternative to the bumper 29 may be a piston-like mechanism that moves
linearly to
actuate a switch, instead of rotating about a fixed pivot point as in the
above. It is not
necessary to use a limit switch with an actuation lever; in an alternative
arrangement, the
bumper 29 (or analogous member) may directly push on the button of a limit
switch.
Also, in some embodiments, a separate spring 330 may not be required. It may
be
possible to rely on the spring of a limit switch to provide a bias or return
force. However,
it may be desirable to use a separate spring to provide for adjustment of
either/both the
range of motion and actuation force of the bumper. In yet another alternative,
a
contactless switch such as an optical emitter-detector pair could he used,
with the skate or
skate blade holder breaking the optical path to trigger the switch.
[0212] In the
illustrated embodiment the slot covers 28 are affixed and always
present, but in an alternative embodiment they could be separate components
that are
placed and locked onto the ends of the skate or skate blade holder by the user
prior to
sharpening. Also, while in the illustrated embodiment the slot covers 28 move
by sliding,
they could alternatively move by rotating on a hinge, telescoping, or rolling
out (like a
breadbox or garage door).
52
[0213] As mentioned above, slot cover designs that differ from those
shown in
Figures 1 and 22A-22D also can be used. For example, with reference to Figures
50-53, another
slot cover configuration 1028 will be described. The second slot cover
configuration is shown
and described in U.S. Provisional Patent Application No. 62/129095, filed on
March 6, 2015 and
entitled SKATE BLADE SHARPENING SYSTEM WITH PROTECTIVE COVERS.
[0214] The slot cover 1028 has a body 1313 that can be connected to
the front
platform portion 22 of the skate sharpener. Disposed along one side of the
body 1313 is an
opening 1314 sized and configured to receive at least a portion of a skate
blade or a skate blade
holder (not shown). The opening 1314 preferably extend to the lowermost
portion of the body
1313 such that a full doorway is defined by the opening 1314.
[0215] The opening 314 is generally closed by a door or bumper 1322.
The
bumper 1322 is sized and configured to contact the skate blade or skate blade
holder. The
bumper 1322 in this configuration is designed to pivot about a generally
horizontal axis (i.e.,
different from the generally vertical axis of the bumper 322 shown in Figure
22A). Thus, the
bumper 1322 is designed to pivot about a top portion of the bumper 1322 (i.e.,
parallel to the Y-
axis of the machine). In some configurations, the bumper 1322 pivots on a
steel dowel.
[0216] The bumper 1322 has a leg 1324 that is connected to the
bumper 1322
such that rotation of the bumper 1322 causes rotation of the leg 1324.
Rotation of the leg 1324
brings the leg 1324 into and out of engagement with a switch 1328. In some
configurations, the
switch is configured to an electrically open state when the bumper 1322 is not
depressed. For
example, the switch 1328 can be mechanically pushed shut without a skate
present but the switch
1328 is electrically open in this state. When brought into contact with a
skate blade or skate
blade holder, for example, the switch 1328 can be relieved or mechanically
released and the
switch 1328 can transition to an electrically closed state, thereby indicating
the presence of the
skate. In some configurations, the leg 1324 is in engagement with a lever or
contact location
1326 of the switch 1328 until the bumper 1322 contacts a skate blade, skate
holder or the like,
which
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causes the leg 1324 to rotate away from the switch 1328. The rotation of the
leg 1324
away from the switch 1328 causes the switch 1328 to go to an electrically
closed state.
This configuration enables the switch 1328 to close the circuit when the
bumper 1322 is
depressed or otherwise in contact with a skate blade, skate blade holder or
the like. The
switch can be configured such that a very short travel distance of the leg
1324 is all that is
needed to open or close the electrical circuit.
[0217] The leg
1324, the bumper 1322 or both can be biased into the closed
position. In some configurations, a biasing member biases the bumper 1322 into
a closed
position, which results in the leg 1324 being also biased into the closed
position. In the
some configurations, the biasing member 1330 is a torsion spring. In the
illustrated
configuration, two torsion springs are provided such that the bumper 1322 can
be loaded
on each lateral side equally. The force provided by the biasing member(s) 1330
can be
selected to provide sufficient force on the switch 1328 to maintain the switch
in the
closed position unless the bumper 1322 is brought into contact with a skate
blade, a skate
blade holder or the like. Other biasing members or mechanisms also can be
used.
[0218] As shown in
Figure 51, a stop 1331 can be positioned to limit the
rotational movement of the bumper 1322. The stop 1331 can limit overstressing
of the
mechanism during engagement with a skate blade, a skate blade holder or the
like. In the
illustrated configuration, the stop 1331 can be defined as in internal lip
that extends into
the path of travel of the bumper 1322. Any other suitable configuration also
can be used.
[0219] With
reference again to Figure 50, the illustrated body 1313 also
includes a lighting feature 1332. The lighting feature 1332 in the illustrated
configuration
is on an upper or top surface of the cover 1028. As shown in Figure 51, a
light pipe 1333
can extend under the lighting feature 1332 or an opening that defines the
lighting feature
1332. The light pipe 1333 can extend from an LED 1334. The LED 1334 can be
mounted to the same printed circuit board as the switch 1328. Other
configurations also
are possible. The lighting feature 1332 can function similarly to the lighting
feature 332
described above (i.e., always on when the cover 1028 is not engaged with a
skate blade,
skate blade holder or the like, flashing when a sharpening is attempted
without the cover
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1028 is a closed position, off when engaged with a skate blade, skate blade
holder, or the
like).
[0220] With
continued reference to Figure 51, the body 1313 can be provided
with skis or slides 1318. The skis 1318, as shown in Figure 52, are sized and
configured
to move within generally circular channels 1319. In the illustrated
configuration, the skis
1318 snap fit to the body 1313. In some configurations, the body 1313 includes
fingers
1323 that secure the skis 1318 to the body 1313. During assembly, a ski guide
could be
used to position the skis 1318 within the channels 1319 and the fingers 1323
of the body
then can be snapped into the skis 1318. Other configurations also are
possible.
[0221] As shown in
Figure 50, the body 1313 also comprises a button 1027.
As described above, depression of the button 1027 raised a rack 1300 and
allowed the
cover 1028 to be moved along the skate sharpener 10. To assist with the
movement, the
body 1313 was provided with a recess 1315. The recess 1315 could receive a
thumb or
the like to assist with movement of the cover 1028. Other configurations also
are
possible.
[0222] The body
1313 also was provided with guards 1316. The guards 1316
extend laterally outward from the body 1313. In the illustrated configuration,
the guards
1316 extend laterally outward in regions generally adjacent to the opening
that receives
the door 1322. In the illustrated configuration, the guards 1316 are
positioned vertically
lower than the bottom surface of the body 1313. The guards 1316 extend
vertically
downward below the bottom surface of the body 1313 but not so far as to
contact the jaws
or another component that may be positioned within the slot of the skate
sharpener 10.
As shown in Figure 53, the guards 1316 are designed to fill a portion of the
slot 24 while
leaving a gap between the guards 1316 sufficient to receive the blade of the
skate during
sharpening operations. As such the outer surfaces of the guards 1316 are
spaced apart a
distance less than the width of the slot 24 while the inner surfaces of the
guards 1316 are
spaced apart a distance greater than a skate blade.
[0223] With
reference now to Figures 54-59, a further slot cover 2028 will be
discussed. The slot cover 2028 is designed and configured to be received by
the front
platform portion 1022 shown in Figure 41. The slot cover 2028 has many aspects
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common with the two slot covers described directly above yet offers many
improvements
to those slot covers.
[0224] The slot
cover 2028 has a body 2313 formed of two main parts, a base
2309 and a cover 2311. In the illustrated configuration, the base 2309 houses
and
comprises most of the operational features of the slot cover 2028 while the
cover 2311
provides more of a cosmetic skin for the slot cover 2028. The cover 2311
protects the
internal components contained within the base 2309. In some configurations,
the cover
2311 can be snap-fit or press-fit with the base 2309. In some configurations,
the cover
2311 and the base 2309 can be secured with mechanical fasteners. In some
configurations, the cover 2311 and the base 2309 can be snap-fit together and
secured
with a threaded fastener 2303 (see Figure 55).
[0225] With
reference to Figure 54, the body 2313 comprises a recess 2315.
The recess can be formed in the base 2309, the cover 2311 or, as shown, both
the base
2309 and the cover 2311. A further recess 2317 can be formed in a top surface
of the
cover 2311. Together, the recess 2315, which is formed in the front surfaces
of the base
2309 and the cover 2311, and the recess 2317 that is formed in the top surface
of the
cover 2311 can be used to move the cover 2028 along the front platform portion
1022.
[0226] The body
2313 also comprises an edge recess 2319. The edge recess
2319 is positioned along the side of the body 2313 that will face the skate
during use.
The edge recess 2319 lowers the height of the body 2313 in a region that will
be adjacent
to the skate during a sharpening operation. By reducing the height of the body
2313 in
this region, a greater variety of skate designs can be accommodated. In some
configurations, the edge recess 2319 and the recess 2317 can be connected to
define a
single recess. In some configurations, the recess 2319 and the recess 2317 can
be
eliminated by lowering the upper surface and replacing the recess 2317 with a
protrusion
or the like to guide a user to move the cover 2028.
[0227] With
reference now to Figures 55 and 56, the base 2309 includes a
door 2322. As described directly above, the door 2322 pivots about its upper
end. Thus,
the door 2322 is configured to pivot or rotate about a generally horizontal
axis. In some
configurations, the door 2322 pivots on a steel dowel.
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[0228] The door
2322 has a leg 2324 that is connected to the door 2322 such
that rotation of the door 2322 causes rotation of the leg 2324. Rotation of
the leg 2324
brings the leg 2324 into and out of engagement with a switch 2328. In some
configurations, the switch is configured to be normally closed and in an
electrically open
state. In such configurations, the leg 2324 is in engagement with a lever or
contact
location (not shown) of the switch 2328 until the door 2322 contacts a skate
blade, skate
holder or the like, which causes the leg 2324 to rotate away from the switch
2328.
Because the switch 2328 is normally closed, the rotation of the leg 2324 away
from the
switch 2328 causes the switch 2328 to go to an electrically closed state. This
configuration enables the switch 2328 to open the circuit when the bumper 2322
is no
longer in contact with a skate blade, skate blade holder or the like. The
switch can be
configured such that a very short travel distance of the leg 2324 is all that
is needed to
close the electrical circuit.
[0229] The leg
2324, the door 2322 or both can be biased into the closed
position. In some configurations, a biasing member biases the door 2322 into a
closed
position, which results in the leg 2324 being also biased into the closed
position. In the
some configurations, the biasing member 2330 is a torsion spring. The force
provided by
the biasing member 2330 can be selected to provide sufficient force on the
switch 2328 to
maintain the switch in the closed position unless the door 2322 is brought
into contact
with a skate blade, a skate blade holder or the like. Other biasing members or
mechanisms also can be used.
[0230] In the
configuration shown in Figure 54, the door 2322 extends well
beyond a lower surface of the base 2309. The degree to which the door 2322
extends
below the lower surface of the base is shown in Figure 57, for example. With
the door
2322 extending below the lower surface of the base 2309, the door 2322 can
pivot toward
the base 2309 until the door 2322 makes contact with the base 2309. As such,
the base
2309 can limit the rotational travel of the door 2322. Other configurations
also can be
used to limit the rotational travel of the door 2322.
[0231] As with the
cover 1028 described directly above, the cover 2028
includes a lighting feature 2332. The lighting feature 2332 in the illustrated
in the
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illustrated configuration is on an upper or top surface of the cover 2311. As
shown in
Figure 56, a light pipe 2333 can extend under the lighting feature 2332 or an
opening that
defines the lighting feature 2332. The light pipe 2333 can extend from an LED
2334.
The LED 2334 can be mounted to the same printed circuit board as the switch
2328.
Other configurations also are possible. The lighting feature 2332 can function
similarly
to the lighting feature 332 described above (i.e., always on when the cover
2028 is not
engaged with a skate blade, skate blade holder or the like, flashing when a
sharpening is
attempted without the cover 2028 is a closed position, off when engaged with a
skate
blade, skate blade holder, or the like).
[0232] With
reference to Figure 57, the base 2309 can be formed to include
fingers 2318. The fingers define generally cylindrical recesses that are sized
and
configured to grasp around the outer profile of the front platform portion
1022. The front
platform portion can include rails 1020 that the fingers 2318 grasp. To
correct for
variations incurred during molding and to provide a desired level of friction,
a spring
2335 can be provided along with a segment of the fingers 2318. The spring 2335
acts to
pull the associated segment of the fingers 2318 inward toward the associated
rail 1020.
The spring can have any suitable configuration. In one configuration, the
spring is a
metal u-shaped member. Other configurations also are possible.
[0233] In addition,
as shown in Figure 56 and in Figure 58, the cover 2028
can include a short rack segment 2300. In the illustrated configuration, the
rack segment
2300 is positioned toward a front portion of the cover 2028. Other
configurations are
possible. The rack segment is engaged by a pawl component 2301. The pawl
component
2301 can be secured to a portion of the front platform portion 1022. In the
illustrated
configuration, a pair of mechanical fasteners, such as threaded fasteners, are
used to
secure the pawl component 2301 in position. The pawl component 2301 can
include a
metal leaf spring secured to a plastic block. The plastic block accurately
locates the leaf
spring. A tunnel 2305 formed within the base 2309 allows the base 2309 to
slide relative
to the pawl component 2301. However, because the pawl component 2301 is
captured
within the base 2309, the pawl component 2301 in combination with the end
walls of the
base 2309 limits the range of motion of the base 2309 along the front platform
portion
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1022. Accordingly, the cover 2028 should be positioned and sized with the
distance
along the slot 1024 that the slot cover 2028 is desired to travel in mind. The
combination
of the rack segment 2300 and the pawl component 2301 (i.e., a passive
bidirectional
ratchet system) work to provide sufficient resistance to movement such that
the cover
2028 will remain in position during sharpening operations.
[0234] The body
2313 also was provided with guards 2316. The guards 2316
extend laterally outward from the body 2313. In the illustrated configuration,
the guards
2316 extend laterally outward in regions generally adjacent to the opening
that receives
the door 2322. In the illustrated configuration, the guards 2316 are extend to
a location
vertically lower than the bottom surface of the body 2313. The guards 2316
extend
vertically downward below the bottom surface of the body 2313 but not so far
as to
contact the jaws or another component that may be positioned within the slot
of the skate
sharpener 10. As shown in Figure 53, the guards 2316 are designed to fill a
portion of the
slot 24 while leaving a gap between the guards 2316 sufficient to receive the
blade of the
skate during sharpening operations. As such the outer surfaces of the guards
2316 are
spaced apart a distance less than the width of the slot 24 while the inner
surfaces of the
guards 2316 are spaced apart a distance greater than a skate blade.
[0235] The printed
circuit board of the cover 2028 can be connected to the
controller of the skate sharpener in any suitable manner. In one
configuration, an FFC
cable can be used to connect the printed circuit board and the controller of
the skate
sharpener. Advantageously, the FTC cable can be concealed within the front
platform
portion 1022 (see FFC in Fig. 57, for example) and can fold and unfold on
itself during
movement of the cover 2028 relative to the front platform portion 1022. The
wires of the
FFC can be installed by being snapped into place and the secured with a
sealant such as
hot-melt adhesive or the like. Other configurations also are possible.
[0236] With
reference now to Figures 81 and 82, the slot cover 2028 is shown
with a youth skate adaptor 2336 installed. In some configurations, due to the
configuration of the skates, such as very small youth sizes, the door 2322 and
the skate
may not make adequate contact. For example, with very small youth sizes, the
location of
the boot of the skate relative to the skate's blade holder, the boot bumps
into the slot
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cover 2028 and does not allow the door 2322 to make contact with the skate
blade or
skate blade holder. In such scenarios, the youth skate adaptor 2336 can be
installed on
the slot cover 2028.
[0237] The youth
skate adaptor 2336 effectively extends the reach of the door
2322 toward the skate blade or skate blade holder. In some configurations, the
adaptor
2336 can be positioned between the guards 2316. In the illustrated
configuration, the
adaptor 2336 can snap fit to the door 2322. The adaptor 2336 can have a
ribbed, stepped
or textured surface 2337 on a projecting portion 2338. In some configurations,
both the
top and the bottom of the projecting portion 2338 can include the textured
surfaces 2337.
[0238] As shown in
Figure 82, a rear of the adaptor 2336 can have a first
member 2339 and a second member 2340. The first and second members 2339, 2340
are
spaced apart from each other. In the illustrated configuration, the first
member 2339 is
vertically above the second member 2340. The first and second member 2339,
2340 each
can define a small recess that receives the door 2322. In the illustrated
configuration, the
first member 2339 is wider than the second member 2340. Together, the first
member
2339 and the second member 2340 enable the adaptor 2336 to snap fit onto the
door
2322. Other configurations of attaching the adaptor 2336 to the door 2322
and/or other
configurations for extending the reach of the door or the skate blade/skate
blade holder
can be used. In addition, while the adaptor 2336 is configured to extend the
reach of the
door 2322 for accommodating youth skates, it is possible that other adaptors
2336 could
be used to address changes in skate design and/or changes in skate blade
holder
technology in the future.
Two Piece Carriage and Two Piece Platform
[0239] With
reference now to Figure 60, another platform and another
carriage option are shown. In the illustrated configuration, the chassis 1014
includes the
front platform portion 1022 and a rear portion 1021. While the configuration
shown in
Figure 5 featured a single piece chassis 1014 that included the front and rear
portions as a
single, monolithic structure (e.g., extrusion), the configuration shown in
Figure 60 has a
two piece chassis 1014 that includes a separate front platform portion 1022
and rear
portion 1021.
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[0240] The front
portion 1022 and the rear portion 1021 can be formed in any
suitable manner. In one configuration, each of the front portion 1022 and the
rear portion
1021 can be separately extruded. In one configuration, the front portion 1022
includes a
recess 1019. The rear portion 1021 includes a portion that is received within
the recess
1019 of the front portion 1022. The rear portion 1021 can be secured to the
front portion
1022 using any suitable technique. In some configurations, mechanical
fasteners can be
used to secure the rear portion 1021 to the front portion 1022. In some
configurations,
one or more threaded fasteners can be used to secure the front portion 1022
and the rear
portion 1021 together (e.g., see the holes shown in the recess 1019 in Figure
58)
[0241] The rear
portion 1021 includes the rails 1060. In the illustrated
configuration, the rails 1060 are supported by a web that connects the rails
1060 to the
main body of the rear portion 1021. In such a manner, the rails 1060 and the
main body
of the rear portion 1021 can be formed as a single extrusion, which improves
manufacturability and decreases assembly time. In some configurations,
however, the
rails 1060 can be formed separate of the main body and secured thereto using
any suitable
technique. For example, the rails 1060 can be secured to the main body using
mechanical
fasteners, such as threaded fasteners, or the like.
[0242] The rails
1060 support the carriage assembly 1070. As described
above, the rails 1060 generally extend in the X direction and the carriage
assembly 1070
is configured to translate along the rails 1060. While the configuration of
the carriage
assembly 70 shown in Figure 4, for example, is a single, unitary, monolithic
configuration
that includes both the carriage 72 and the support framework that carries the
related
components, the carriage assembly 1070 shown in Figures 60 and 61, for
example, has
been separated out into two or more components.
[0243] As
illustrated best in Figure 61, the illustrated carriage assembly 1070
comprises the carriage 1072 and the support framework 1074. By separating the
carriage
1072 from the support framework 1074, it is possible to make alignment changes
between
the carriage 1072 and the support framework 1074 such that manufacturing
tolerances do
not result in any significant misalignments. In some configurations, rather
than making
the carriage 1072 and the support framework 1074 as fully separable
components, the
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carriage 1072 and the support framework 1074 can be formed as a single user
yet having
the carriage 1072 and the support framework 1074 flexibly interconnected such
that
alignment adjustments between the two components 1072, 1074 can be made and
then the
two can be locked together in the desired orientation. For example, a
mechanical
fastener, such as a threaded fastener, for example, can be used to secure the
two
components in a desired orientation. In some configurations, as shown in
Figure 62, the
framework 1074 includes four slots 1075, two sets of two aligned slots 1075
with the two
sets extending in different directions. For example, two slots 1075 can be at
an angle to
the direction of travel while two slots 1075 can be normal to the direction of
travel. Such
a configuration facilitates alignment through the use of the slots and the
desired alignment
can be secured by tightening the threaded fasteners into the upper carriage
1072. Any
other suitable configuration can be used keeping in mind a desire to
facilitate alignment
between the interface with the rails 1060 (i.e., which interaction guides the
direction of
travel of the carriage) and the axis of rotation of the grinding wheel (i.e.,
which dictates
the sharpening action).
[0244] Over time,
wear can occur between the carriage assembly 1070 and the
rails 1060. Accordingly, a method and/or assembly to accommodate the wear and
increase the life of the assembly would be desirable. One such method and/or
assembly
can include providing the interface between the carriage assembly 1070 and the
rails 1060
with wear members. In the illustrated configuration, the carriage assembly
1070
comprises guide channels 1075. The guide channels 1075 extend along at least a
portion
of the length of the carriage 1072. In the illustrated configuration, the
guide channels
1075 extend along the full length of the carriage 1072. The guide channels
receive the
rails 1060. To reduce wear of the guide channels 1076, one or more bushing
liner 1076
can be provided. In the illustrated configuration, two bushing liners 1076 are
positioned
along each of the guide channels 1075. The bushing liners 1076 can be spaced
apart
along the length of the guide channel 1075. Other configurations are possible.
[0245] With
reference to Figure 64, the bushing liners 1076 do not define a
full circle such that the bushing liners 1076 do not fully surround the rails
1060 (see
Figure 60). The bushing liners 1076 can extend only a portion of a full
circle. In some
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configurations, the bushing liners 1076 extend more than 180 degrees and less
than 360
degrees. In some configurations, the liners 1076 extend between about 220
degrees and
320 degrees.
[0246] While
bushing liners 1076 can help improve the movement of the
carriage 1072 along the rails 1060, wear over time can affect the consistency
of
movement. Thus, one or more of the illustrated bushing liners 1076 are biased
into
abutment with the rails 1060. In the illustrated configuration, two bushing
liners 1076
that engage a single rail 1060 are biased into abutment with that rail 1060.
With
reference to Figure 64, the bushing liner 1076 is engaged by a floating
bushing 1077. The
floating bushing 1077 is positioned within a recess of the carriage 1072. The
floating
bushing 1077 can extend the full length of the bushing liner 1076 or some
portion of the
bushing liner length. In the illustrated configuration, the floating bushing
1077 extends
the full length of the bushing liner 1076. The floating bushing 1077 can
include an
engagement face 1079 that is in contact with at least a portion of the bushing
liner 1076.
In some configurations, the engagement face 1079 is arcuate or curved. In some
configurations, the engagement face 1079 contacts a portion of the bushing
liner 1076
that is generally centrally located between the two edges that define the open
portion of
the circle. In some configurations, the engagement face 1079 is positioned to
contact a
portion of the bushing liner 1076 that is diametrically opposed to the opening
defined
along the bushing liner 1076. Other placements also are possible.
[0247] A biasing
member 1081 can be captured between the floating bushing
1077 and a threaded member 1085. The threaded member and/or the floating
bushing
1077 can include a recess that receives the biasing member 1081. In the
illustrated
configuration, the floating bushing 1077 includes a recess that surrounds a
post member
and at least a portion of the biasing member 1081 is received within the
recess and
supported by the post member. The biasing member 1081 urges the floating
bushing
1077 into engagement with the bushing liner 1076. Other configurations are
possible.
Advantageously, by incorporating a pre-loaded bushing and/or pre-loaded
bushing liner,
it is possible to maintain a relatively consistent low-level friction
component between the
carriage assembly 1070 and the rails 1060 for a relatively long period of time
during
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which wear will be occurring. As such, improved performance results from the
use of the
pre-loaded bushing and/or bushing liner.
Grinding Wheel to Blade Alignment Details
[0248] Figure 23 is
an end view of the carriage assembly 70, similar to Figure
14 but showing a section view at the location of the pivot spindle 240.
Certain details are
shown more clearly in the close-up view of Figure 24.
[0249] The pivot
spindle 240 is secured at each end to the carriage 72. A pivot
section 400 of the motor arm 78 is mounted on the pivot spindle 240 by a
combination of
bearings 402, 404 and bushings 406, 408. Shown on the right in this view is a
spring 410
disposed in compression between the front wall of the carriage 72 and an inner
race 412
of the bearing 404. Shown on the left is the spindle gear 253 which is
disposed on a hub
or nut 414 having screw threading engaging corresponding screw threading on
the pivot
spindle 240. It will be appreciated that the gear and threading features may
be integrated
into a single component as an alternative. Arranged between the nut 414 and an
inner
race 416 of the bearing 402 is a washer 418 and a collar portion 420 of the
bushing 406,
including a detent mechanism as described below.
[0250] The mounting
of the motor arm 78 on the bearings 402, 404 permits
the motor arm 78 to pivot about the pivot spindle 240 so that the grinding
wheel 36 can
follow the profile of the bottom face of the skate blade during sharpening (as
described
above with reference to Figures 7 and 8). The bushings 406, 408 provide for
low-friction
transverse (Y-axis) movement of the motor arm 78 (left to right in Figure 23).
The spring
410 provides a biasing force against a side face of the inner race 412 of the
bearing 404,
urging the motor arm 78 rearward (leftward in Figure 23). The combination of
the
threaded nut 414, washer 418 and collar portion 420 of the bushing 406 acts as
a stop
member against which the motor arm 78 is urged. Specifically the force from
spring 410
is transmitted to the nut 414 via a set of mechanical components including the
bearing
404, pivot section 400, bearing 402, collar portion 420 of the bushing 406,
and washer
418 and detent mechanism described below.
[0251] The
transverse or Y-direction (left to right in Figure 23) position of the
motor arm 78 is varied by rotation of the nut 414, which occurs by user
rotation of the
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adjustment knob 242 (Figures 13, 14) and resultant rotation of the adjustment
axle 254
and gears 256, 252 as described above with reference to Figure 14. As the nut
414 rotates,
the screw action causes it to also move transversely in the Y direction along
the pivot
spindle 240, and due to the pressing force from the spring 410 the motor arm
78 moves
transversely along with it. The bushing 406 slides along an outer surface of
the pivot
spindle 240, and the inner race 412 of bearing 404 is pressed onto bushing
408, which
slides along an outer surface of pivot spindle 240. The bushing 408 may
alternatively
include a flange or collar portion similar to collar portion 420 of the
bushing 406.
[0252] The nut 414
and washer 418 are co-configured to form a detent
mechanism providing several detent locations for a rotation of the nut 414,
helping reduce
or eliminate the likelihood of undesired transverse movement of the motor arm
78 after
an alignment operation has been performed and a sharpening operation has
begun.
Specifically, the front face (rightward in Figure 23) of the nut 414 has a
shallow
depression in which is disposed a ball, and the washer 418 has an array of
corresponding
holes or depressions arranged in a circle. As the nut 414 is rotated the ball
moves from
one hole or depression of the washer 418 to the next, requiring a small force
to push the
ball sufficiently out of the first hole/depression to enable it to travel to
the next. This
force is easily generated by the user's rotation of the adjustment knob 242
but not by
vibration or other mechanical forces occurring during sharpening operation.
[0253] Figure 25 is
a downward view encompassing the jaws 90 and the
grinding wheel 36 and motor arm 78 underneath. The jaws 90 are shown in the
closed
position, slightly spaced apart as they are when retaining a skate blade (not
shown). This
view is of an aligned position in which a centerline 430 of the grinding wheel
36 is
aligned with a centerline 432 of a sharpening position of the skate blade
(midway
between the clamping surfaces of the jaws 90). In configurations including a
jaw guard
1380, the jaw guard 1380 can be used to provide a desired vertical position
for alignment
and calibration. As discussed above, the jaw guard 1380, by making contact
with the
spindle 1082, guides the grinding wheel 1036 downward away from the jaws
1090F,
1090R. In the same manner, the jaw guard 1380 can ensure that alignment occurs
at a
desired vertical position each time calibration or alignment is undertaken.
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[0254] In some
configurations, one or more lighting feature can be
incorporated into the jaw guard 1380. In some configurations, the lighting
feature can be
positioned adjacent to the jaw guard 1380. In some configurations, an LED or
the like
can be mounted in the jaw guard 1380. For example, one or more holes 1381 (see
Figure
45) can be provided in the jaw guard 1380 in which the LED can be mounted. In
other
configurations, the LED can be mounted anywhere on the chassis or within the
compartment defined within the skate sharpener.
[0255] The LED can
he illuminated when the grinding wheel is being aligned.
For example, in configurations having an alignment mode, the lighting feature
in, on or
around the jaw guard can be activated when the skate sharpening device enters
into the
alignment mode or at some time period during the alignment mode. The lighting
feature
thereby can illuminate the area surrounding the alignment features.
[0256] It will be
appreciated that the grinding wheel 36 can be moved
transversely (up and down in the view of Figure 25) by the above-described Y-
adjustment
mechanism, changing the position of the grinding wheel centerline 430 with
respect to the
centerline 432 of the skate blade. In general there is a small range of
uncertainty in the
position of the grinding wheel 36 relative to the centerline 432 based on
mechanical
tolerances as well as planned variability, such as varying sizes of grinding
wheels 36 that
the system supports, etc. The adjustment mechanism enables a user to obtain
accurate
alignment to achieve as closely as possible the idealized arrangement of
Figure 2, i.e.,
perfectly symmetrical curvature of the bottom surface 42 of the skate blade 40
about its
centerline 432, so that the edges 44 lie in the same plane perpendicular to
the X-Z plane
of the skate blade 40. In the present context, the required accuracy of
alignment is to
within approximately +/- .001". It will be appreciated that this level of
accuracy is
generally not possible using simple naked-eye observation of the degree of
alignment
between the grinding wheel 36 and skate blade 40. Thus features that aid
alignment to
this degree are disclosed.
[0257] Figure 25
also shows certain features of the jaws 90 pertaining to
alignment. First is a central open area 434 through which the grinding wheel
36 can be
viewed and a separate alignment tool (described below) is received. Thus the
jaws 90 are
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left with endward clamping portions 436. Second are notches 438 formed in the
front jaw
90-F which receive corresponding protrusions from the alignment tool so that
the
alignment tool is properly oriented and located precisely in the left-to-right
direction of
Figure 25. This precise locating in turn provides for close spacing of an
alignment feature
of the alignment tool with a corresponding feature of the grinding wheel 36,
as described
more below.
[0258] Figure 26
illustrates the alignment tool 440 as it is located during use.
It has a lower blade-like portion 442 and an upper portion 444 holding a
magnifying lens
446. The blade-like portion 442 is clamped between the jaws 90 in the same
sharpening
position that the skate blade 40 occupies when being sharpened. In this view
the front jaw
90-F is omitted for ease of description. The blade-like portion 442 extends
downward to
support a flag 448 that functions as a first visual reference feature as
explained below. In
one embodiment the flag 448 is a thin member secured flat against a surface of
the lower
portion 442. It is thus precisely spaced from the centerline 432 of the jaws
90 (Figure 25)
when the alignment tool 440 is clamped in the illustrated position. In the
illustrated
embodiment this spacing is on the order of one-half the width of the grinding
wheel 36.
Also shown in Figure 26 are machined shoulder portions 450 extending out of
the page in
this view. Bottom edges of the shoulder portions 450 sit on top of the endward
clamping
portions 436 of the jaws 90 (Figure 25), except for the slightly longer
protrusions 452 that
are received by the notches 438 (Figure 25). It will be noted that the flag
448 is opposite
the grinding wheel 36 along a horizontal diameter. In other embodiments the
flag 448
may be formed integrally with the lower portion 442.
[0259] In use, a
user opens the jaws 90 and inserts the alignment tool 440,
locating it so that the shoulder portions 450 sit on top of the endward
clamping portions
436 of the jaws 90 and the protrusions 452 are received by the notches 438.
The user then
closes the jaws 90 so that the alignment tool 440 is retained with the blade-
like portion
442 in the same position as a skate blade 40 is retained during sharpening.
The carriage
70 is then moved to bring the grinding wheel 36 to the position shown in
Figure 26, i.e.,
with its outer surface just slightly spaced from the flag 448. This movement
may be
automatic or manual, and if automatic it may be user- initiated (such as via
the user
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interface 34 of Figure 1) or in some manner auto-initiated by detection of the
presence of
the alignment tool 440.
[0260] In one
embodiment the movement of the grinding wheel 36 into the
alignment position of Figure 26 may employ the same components used for moving
the
carriage 70 during sharpening, i.e., the carriage motor 260 and rack-and-
pinion
mechanism. The grinding wheel 36 may be moved until it encounters the
alignment tool
440, which can be sensed as an increase in the drive current through the
carriage motor
260. Upon sensing this encounter, the controller 32 provides one or more brief
pulses of
reverse drive current to move the grinding wheel 36 slightly away from the
alignment tool
440 to allow for the Y-direction adjustment of the motor arm and grinding
wheel 36 as
described further below. The movement away from the encounter position could
alternatively be guided by use of a position encoder on the motor, for example
if greater
positional accuracy is needed.
[0261] In some
configurations, the motor 260 can be a stepper motor 1260. In
such configurations, it is possible to specifically define a calibration
position. The
stepper motor can cause movement of the grinding wheel to the location desired
for the
alignment operation. For example, the number of steps can be counted and the
calibration positon can be determined based upon the number of steps.
Moreover, the
number of steps to a grinding wheel change location can be counted. As such,
movement
of the carriage to a location that allows for interchanging of grinding wheels
can be
provided with consistency and repeatability.
[0262] With
reference to Figure 65, the skate sharpener 1010 is illustrated
with an end cover removed. The end cover defines a motor compartment that
contains
the motor 1260. The motor 1260 can be mounted to one or more heat sinks 1261.
The
heat sinks 1261 help to reduce the operating temperature of the motor 1260. A
bracket
1262 also mounts the motor 1260 in position within the motor compartment. A
drive
pulley 1263 can be mounted to the shaft of the motor 1260. The pulley,
bracket, motor
and heat sink can be positioned within the motor compartment. As shown in
Figure 38
and Figure 42, a vent 1264 can be provided in the end cover 1265. The vent
1264
facilitates air exchange during operation to also help lower the operating
temperature of
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the motor 1260. Other configurations are possible. With reference to Figure
64, the
carriage assembly 1070 includes a belt grabber 1266. The belt grabber 1266 can
be
secured to the carriage assembly 1070 in any suitable manner. In one
configuration,
mechanical fasteners, such as threaded fasteners, can be used to secure the
belt grabber
1266 to the carriage 1072. As shown in Figure 66, an idler pulley 1269 can be
positioned
at an opposite end of the skate sharpener 1010 from the motor 1260. Thus, the
belt 1268
can wrap around the two pulleys 1263, 1269 and be secured to the carriage
assembly
1070.
[0263] The belt
grabber 1066 can include a channel 1267 that receives a belt
1268 and secures the belt grabber 1066 in position along the belt 1268. In
some
configurations, a bend or the like is disposed along the channel 1267. In some
configurations, the channel 1267 is generally V-shaped. In some
configurations, the
channel 1267 includes one or more teeth along the length of the channel. In
some
configurations, one wall that defines the channel 1267 includes a plurality of
teeth. In
some configurations, the belt 1268 includes teeth and the channel 1267
includes teeth that
mesh with the teeth of the belt 1268. Other interlocking or coupling
structures also can
be used to join the belt 1268 to the carriage assembly 1070.
[0264] Figure 27 is
a view downward through the magnifying lens 446. An
area around the flag 448 is visible, with the grinding wheel 36 slightly
spaced apart from
it. The grinding wheel 36 has an annular notch 454 formed near its front face,
which
functions as a second visual reference feature as explained below. The notch
454 is
precisely spaced from the centerline 430 of the grinding wheel 36 (Figure 25)
by the same
amount as the spacing between the flag 448 and the centerline 432 between the
jaws 90.
Thus, when the flag 448 is aligned with the notch 454, as is shown in Figure
27, the
centerline 430 of the grinding wheel 36 is precisely aligned with the
centerline 432
between the jaws 90, and hence with the centerline of the skate blade 40.
[0265] As
indicated, Figure 27 shows the aligned position. It will be
appreciated that when the centerline 430 of the grinding wheel 36 is not
aligned with the
centerline 432 between the jaws 90, then the notch 454 is correspondingly
offset from the
flag 448 (in the up and down direction in Figure 27) as an indication of such
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misalignment. A user can look through the magnifying lens 446 to view the area
of the
flag 448 and simultaneously turn the adjustment knob 242 (Figure 14) to move
the motor
arm 78 and grinding wheel 36 in the transverse (Y) direction (up and down in
Figure 27)
to bring these centerlines into alignment, thereby accurately aligning the
grinding wheel
36 with the bottom of the skate blade 40 for a sharpening operation.
[0266] Figure 28 is
a simplified flow diagram for a process of aligning a
grinding wheel to a retained skate blade. The process includes at 460 visually
observing
an area in which first and second visual reference features of the skate blade
sharpening
system are located, where the first visual reference feature has a first
predetermined
location relative to a centerline of the retained skate blade, and the second
visual
reference feature is carried by a motor arm that also carries the grinding
wheel and that
has a second predeteimined location relative to a centerline of the grinding
wheel. In one
embodiment the first visual reference feature may be a feature like flag 448
on a separate
fixture or tool such as the alignment tool 440 that is clamped in the
sharpening position,
so that the first visual reference feature is temporarily placed in position
for the alignment
operation. In alternative embodiments the first visual reference feature may
be built in to
the sharpening system 10, such as by incorporation into the jaws 90 for
example. In one
embodiment the second visual reference feature may be a notch or similar
feature
incorporated on the grinding wheel 36, such as described above.
[0267] The process
further includes at 462 operating an adjustment
mechanism while visually observing the area where the visual reference
features are
located to bring them into alignment with each other. This brings the grinding
wheel and
the retained skate blade into an aligned position in which the centerline of
the grinding
wheel is aligned with the centerline of the retained skate blade. In one
embodiment the
adjustment mechanism may be configured and used such as described above, but
the
adjustment mechanism may be realized in different ways in alternative
embodiments.
[0268] Referring
again to Figures 26 and 27, the visual reference features in
the form of the flag 448 and notch 454 provide for detection of parallax that
could affect
accuracy of the adjustment. As generally known, parallax is a phenomenon by
which two
objects that are actually misaligned in a particular direction nonetheless
appear aligned
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when viewed from a different direction. In the present context, parallax could
potentially
occur if a user is not directly above the flag 448.
[0269] Because the
flag 448 has a height much greater than its thickness, if a
user were viewing from a slightly incorrect angle then the flag 448 would
appear thicker
than when viewed from directly above. A user can adjust his/her viewing angle
until the
thickness is minimized. Alternatively, if light is striking the sides of the
flag 448 then the
illuminated sides will be slightly visible when the flag 448 is viewed off-
angle. The notch
454 also provides for parallax detection, because it will only he visible as a
notch when
viewed from directly above. When the area of the notch 454 is viewed off-
angle, the
notch is visually filled by its own inside surface.
[0270] It is noted
that the placement of the notch 454 toward an edge of the
grinding wheel 36 has significance. Proper grinding occurs at the center of
the grinding
wheel 36, so if the alignment mark were placed at the center of the grinding
wheel 36
then it would be affected by grinding and potentially lose its ability to
function as an
alignment mark. It might even be erased completely before the end of the
usable lifetime
of the grinding wheel 36. When formed as a notch or similar feature, it might
also
compromise the quality of the sharpening. By placing the alignment mark in the
form of
the notch 454 nearer the edge or face of the grinding wheel 36 it is not
affected by the
normal wearing of the abrasive over a period of use, and it does not interfere
with
grinding.
Alternative Grinding Wheels and Alignment Wheels
[0271] With
reference now to Figures 67-75, a further configuration for a
grinding wheel 3000 will be described. As illustrated, the grinding wheel 3000
generally
comprises a grinding ring 3002 and a hub 3004. The grinding ring 3002
generally is a
single metallic component while the hub 3004 comprises one or more components
with
one or more of the one of more components being formed of a non-metallic
material. In
some configurations, the entire hub 3004 is formed of non-metallic materials
except for
the presence of an enclosed or encased or otherwise secured communications
component.
[0272] With
reference to Figure 71, the grinding ring 3002 can be configured
with an abrasive outer surface 3006. As described above, the abrasive outer
surface is
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used for removing material from a skate blade during operation of the skate
sharpener. In
one embodiment the abrasive surface may include a diamond or cubic boron
nitride
(CBN) coating, deposited by electroplating for example. The grinding ring 3002
preferably is formed of steel or similar rigid, strong metal, and it may be
fabricated from
steel tubing or bar stock. The grinding ring 3002 has an outer surface that is
formed to a
desired radius. For example, the grinding ring 3002 is CNC machined to a
desired radius
(i.e., to match a desired radius of hollow). By forming the outer surface to
the desired
radius of hollow and then plating the abrasive to this formed out surface,
dressing of the
grinding surface can be eliminated before and/or during use. In some
configurations, the
ring 3002 has a diameter of 42 mm.
[0273] The grinding
ring 3002 preferably comprises an exposed inner surface
3003. In other words, this inner surface 3003 is not covered by any portion of
the hub
3004. In some configurations, the edge between a radially extending surface
3001 and
the axially extending inner surface 3003 is chamfered. The chamfered corner
assists with
mounting of the grinding wheel 3002 onto the receiving portion of the skate
sharpening
system.
[0274] In some
configurations, the inner surface 3003 has a diameter of
between 25 mm and 100 mm. In some configurations, the inner surface 3003 has a
diameter of 37 mm. In some configurations, the inner surface 3003 has an axial
length of
between 1 mm and 5 mm. In some configurations, the axial length of the inner
surface
3003 is at least 2.0 mm. In some configurations, the axial length of the inner
surface
3003 is 2.3 mm In other words, a distance of at least 2 mm is provided between
the
radial surface 3001 and any other component such that a mounting clearance is
defined.
Such configurations advantageously result in an axial gap being initially
formed between
the hub 3004 and the end surface of the arbor (see Figure 9). This axial gap
facilitates a
solid face-to-face mating between the metallic grinding ring and the metallic
arbor. Thus,
heat transfer between the metallic grinding ring 3002 and the metallic arbor
can be
enhanced through the direct contact. The axial gap is initially present and
through the
force applied by the retention nut 508, the axial gap is eliminated as the hub
3004 yields
under the force. Once the axial gap has been eliminated, the retention nut
bottoms out as
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there is no additional rotation remaining in the nut and this gives positive
feedback to the
user that sufficient torque has been applied to the nut. Without a feature
such as this, the
user would have a much harder time deciding how much torque was sufficient to
secure
the grinding ring. This configuration provides the radial surface 3001 of the
grinding
ring 3002 for aligning the grinding ring with the arbor. Because the arbor and
grinding
ring are sized within a close tolerance, the mating surfaces of the grinding
ring and arbor
can provide the source of the connection to the motor, and not the hub 3004,
which is
merely used to provide a surface that abuts against a nut or other threaded
fastener. As
such, creating a true rotation of the ring 3002 is more likely than in
situations where the
hub 3004 defines the connection location.
[0275] The grinding
ring 3002 comprises an inner groove 3008. The inner
groove 3008 is formed on an inner surface of the grinding ring 3002. At least
one face of
the inner groove 3008 defines a catch surface. The catch surface, as will be
described,
interfaces with the hub 3004 to lock the grinding ring 3002 to the hub 3004.
To simplify
manufacture, the groove 3008 preferably is centered between axial ends of the
grinding
ring 3002.
[0276] With
continued reference to Figure 71, the hub 3004 comprises a first
hub component 3010 and a second hub component 3012. The first and second hub
3010,
3012 components can be secured together in any suitable manner. In some
configurations, the first hub component 3010 and the second hub component 3012
can
snap-fit together.
[0277] With
reference to Figure 74, the first hub component can comprise an
axially extending sleeve portion 3014. An inner surface of the sleeve portion
3014 can be
configured to receive an axle of the skate sharpener 1010. An outer surface of
the sleeve
portion 3014 can include a shoulder 3016. The shoulder 3016 can be formed by
an outer
recess or the like. In some configurations, the shoulder 3016 does not extend
fully around
the sleeve portion 3014. In the illustrate configuration, the shoulder 3016 is
interrupted
by at least one finger 3018, as shown in Figure 75.
[0278] As also
shown in Figure 74, the first hub component 3010 also
includes a recess 3020 defined on an opposite end to the location of the
finger 3018. The
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recess 3020 extends radially outward to an outer shoulder 3022. The outer
shoulder 3022
is slightly smaller in outer diameter than the grinding ring 3002. The recess
3020 defines
a cavity that receives a label 3024 or the like. The label 3024 can be used to
help visually
identify one or more characteristics of the grinding wheel 3000.
[0279] With
reference again to Figure 74, the second hub component 3012
also comprises a central sleeve portion 3026. The central sleeve portion 3026
includes
one or more ridge 3028 or the like, The ridge 3028 is sized and configured to
interface
with the shoulder 3016 of the first hub component 3010. In the illustrated
configuration,
the ridge 3028 extends circumferentially around an inner portion of the
central sleeve
portion 3026. As discussed with the first hub component 3010, the ridge 3028
is
interrupted by one or more fingers 3030. In order to accommodate the finger
3018 of the
first hub component 3010, the fingers 3030 of the second hub component define
a gap.
The gap advantageously enables the ridge 3028 to have sufficient flex to allow
the second
hub component 3012 to snap fit to the first hub component 3010. In this
manner, once
secured together, the first and second hub components 3010, 3012 are difficult
to
separate. In some configurations, the first and second hub components 3010,
3012 are
secured together without the need for an adhesive, cohesive or welding agent.
[0280] With
reference to Figure 73, a chamber 3032 can defined between the
first and second hub components 3010, 3012. The chamber 3032 receives one or
more
communication components. In one configuration, a circular REID tag 3034 is
positioned
within the chamber 3032. In some configurations, more than one RFD tag can be
positioned within the chamber. In some configurations, the communication
component is
annular in shape. In some configurations, the communication component is more
than
one communication component and not annular in shape. When the two hub
components
3010, 3012 are secured together, the communications components 3034 are
protected
from tampering. In some configurations, any attempts to gain physical access
to the
communications components 3034 will result in damage or mutilation of one or
more of
the hub components 3010, 3012. As such, the security of the communications
component
3034 can be protected.
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[0281] With
reference to Figure 72, the second hub component 3012 includes
one or more ribs 3036. In some configurations, the ribs 3036 can be formed on
the first
hub component 3010 or a portion of the ribs 3036 can be formed on each of the
first hub
component 3010 and the second hub component 3012. The ribs 3036 act as stand-
offs for
the communications component 3034 while securing the communications component
3034 in a desired axial location relative to the grinding ring 3002.
[0282] Because the
communication component 3034 works by receiving
energy from the sensor module 1222, the communications component 3034
preferably is
spaced apart from the metal of the grinding ring 3002 to improve performance.
In other
words, as shown in the sectioned view of Figure 73, for example, the ring 3002
is axially
offset from the communications component 3034. In some configurations, the
axial
offset is between 0.5 mm and 20 mm. In some configurations, the axial offset
is between
1 mm and 10 mm. In some configurations, the axial offset is between 2 mm and 3
mm.
In some configurations, the axial offset is 2.5 mm. In some configurations,
the grinding
wheel can be dish-shaped but allow sufficient radial offset from the outer
ring of the
grinding wheel to facilitate communications. Similarly, where the grinding
wheel is
formed of a metallic material, holes or openings could be provided in the
region of the
communications component 3034 to improve communication perfoimance.
[0283] In some
configurations, when the grinding wheel 3000 is mounted to
the skate sharpener 1010, the location of the communications component 3034 is
axially
offset between 10 mm and 40 mm from the RFID antenna component within the
sensor
module 1222. In some configurations, the RFID antenna component and the
communications component 3034 are axially offset between 15 mm and 25 mm. In
some
configurations, the axial offset is 20 mm. Such a configuration and such
spacings have
been found to position the communications component 3034 close enough to the
RFID
antenna of the sensor module 1222 to power the communications component 3034
yet
distance the communications component 3034 from the grinding ring 3002
sufficiently to
reduce the interference and energy absorption caused by the grinding ring
3002. Thus, in
the illustrated configuration, there is an axial offset in location between an
axially
outermost portion of the grinding ring 3002 and the axial location of the
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component 3034. Moreover, the communications component 3034 is mounted to a
non-
metallic component (e.g., the hub 3004.
[0284] Figures 29-
34 illustrate an alternative embodiment employing a
slightly different alignment scheme and alignment components. Shown in Figure
29 is an
alternative grinding wheel 500 lacking an alignment feature such as the
alignment notch
454 of the grinding wheel 36 as described above. The grinding wheel 500 may in
all other
respects be similar or identical to the grinding wheel 36. It also may be
somewhat simpler
and less expensive to manufacture.
[0285] When
manufacturing the grinding wheel 36, certain processing steps
are used specifically to form the notch 454. Such steps are not required in
manufacturing
the grinding wheel 500. Moreover, the additional grinding wheel width that
provides
sufficient footprint to accommodate the notch 454 is less desired from a true-
spin
perspective. Thus, in some configurations, providing a grinding wheel that
does not
include the notch 454 may be desirable. However, the alignment between the
grinding
wheel and the skate blade still is desired. As described below, a separate
alignment wheel
is used for the alignment process.
[0286] Figure 30
shows an alignment wheel 502 in position on the axle 208 of
the spindle 82.
[0287] The
alignment wheel 502 has precise similarity to the grinding wheel
500 so that it occupies the same wheel-mounting location against the arbor 212
as
occupied by the wheel 36 as described above. As shown, the alignment wheel 502
includes an alignment notch 504 toward its outer face, similar to the notch
454 on
grinding wheel 36. The notch 504 serves as a visual reference feature in the
same manner
as described above for the notch 454. In this embodiment as described more
below, an
alignment process results in aligning the wheel-mounting location with the
skate blade
through use of the alignment wheel 502. The alignment wheel 502 is then
replaced with
the grinding wheel 500 which is then inherently aligned with the skate blade
because it
occupies the aligned wheel-mounting location. When the alignment wheel 502 has
been
aligned and then replaced with the grinding wheel 500, the centerline of the
grinding
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wheel 500 is precisely aligned with the centerline 432 of the jaws 90, just as
described
above with reference to Figures 25 and 27.
[0288] Figure 31
shows additional details. The alignment wheel 502 is
preferably of one-piece construction of a material such as metal or
thermoplastic and
mechanically preferably mimics the multi-piece grinding wheel assembly 36 (see
Figure
9). As indicated, the alignment wheel 502 is mounted against the arbor 212 at
a wheel-
mounting location 506 and is retained by a retention nut 508.
[0289] In some
embodiments, the alignment wheel is a noncircular shape. For
example, the alignment wheel can be oblong, square, octagonal, or another
geometric
shape. In some embodiments the alignment wheel can be asymmetric, where the
alignment wheel is not symmetric about an axis.
[0290] Figure 32 is
a counterpart of Figure 25 for an embodiment using the
alignment wheel 502. This view is of an aligned position in which a centerline
510 of the
alignment wheel 502 is aligned with the centerline 432 of the sharpening
position of the
skate blade (midway between the clamping surfaces of the jaws 90). The
alignment wheel
502 can be moved transversely (up and down in the view of Figure 32) by the
above-
described Y-adjustment mechanism, changing the position of the alignment wheel
centerline 510 with respect to the centerline 432 of the skate blade.
[0291] Figure 33 is
a counterpart of Figure 26 showing use of an alignment
tool 512 similar to the alignment tool 440. In particular, the alignment tool
512 includes a
flag 514 serving as a visual reference feature in the same manner as the flag
448 of
alignment tool 440. The alignment tool 512 differs in appearance from the
alignment tool
440, but not in its essential structure and function. The alignment tool 512
could be used
in an alignment scheme using a notched grinding wheel 36 such as described
above, and
the alignment tool 440 could be used in an alignment scheme using a separate
alignment
wheel 502 as described with reference to Figures 29-35.
[0292] Figure 34 is
a counterpart of Figure 27 showing a similar downward
view during an alignment process. An aligned position is shown in which the
flag 514 is
aligned with the notch 504 of the alignment wheel 502.
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[0293] In some
embodiments, the motor arm may be configured to incorporate
the second visual reference feature. The position of the second visual
reference feature on
the motor arm can be positioned such that the motor arm can be moved to an
aligned
position without using a separate alignment component (such as an alignment
wheel). In
some embodiments, the second visual reference feature can be incorporated into
the arbor
212. For example, the second visual reference feature can be an alignment
notch
positioned on the arbor 212. In some embodiments, the second visual reference
feature
can be positioned on another location of the motor arm..
[0294] Figure 35 is
a counterpart of Figure 28, illustrating a process of
aligning the grinding wheel 500 to a retained skate blade. The process
includes use of a
first visual reference feature having a first predeteimined location relative
to a centerline
of the sharpening position. In one embodiment a first visual reference feature
can be a
flag of an alignment tool (e.g., flag 514 of alignment tool 512).
[0295] The process
of Figure 35 includes, at 520, mounting an alignment
wheel at a wheel- mounting location (e.g., location 506) on a motor-driven
spindle of the
sharpening system, the spindle being movable transversely by an adjustment
mechanism
to vary a relative position between the spindle and the sharpening position.
The alignment
wheel has a second visual reference feature (e.g.. notch 504 of alignment
wheel 502)
having a second predetermined location relative to a centerline of the
grinding wheel
when subsequently occupying the wheel- mounting location in a sharpening
operation.
[0296] The process
further includes, at 522, operating the adjustment
mechanism to bring the first visual reference feature into alignment with the
second
visual reference feature, thereby bringing the wheel-mounting location of the
spindle to
an aligned position in which the centerline of the grinding wheel when
occupying the
wheel-mounting location is aligned with the centerline of the skate blade
position. The
alignment may be achieved by visually monitoring relative positions of the
visual
reference features while operating the adjustment mechanism.
[0297] Although the
alignment processes and apparatus as described herein
contemplate a human user who looks through the magnifying lens 446 and rotates
the
adjustment knob 242, it will be appreciated that in alternative embodiments a
more
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automated process may be used. For example, some manner of machine vision or
other
apparatus may be used to monitor relative position between the grinding wheel
36 and
alignment tool or between the alignment wheel 502 and the alignment tool, and
the
adjustment mechanism may be driven by an adjustment motor provided with an
electrical
adjustment signal. In an embodiment employing automation, a controller can
then
perform the process of Figure 28 or Figure 35 based on position information
from the
position-monitoring apparatus and by generating the electrical adjustment
signal to
change the relative positions of the respective components accordingly until
an aligned
position is detected. Alternatively, in a less automated system, the offset
may be
displayed in numbers or graphics to a human user who controls the adjustment.
Dust Capture and Control
[0298] During any
grinding operation, the skate sharpener 1010 will generate
dust or debris associated with the metal being removed from the skate blade
being
sharpened. Desirably, the skate sharpener 1010 can be configured for use in a
household
environment. For at least this reason, dust containment is desired. More
particularly,
because the skate sharpener 1010 can have one or more light transmissive or
transparent
components that allow users or observers to see inside of the skate sharpener,
dust
containment and management is a consideration.
[0299] With
reference now to Figures 76-79, an example of a dust
containment and removal configuration for the skate sharpener 1010 will be
described.
The configuration provides a flow of air through the machine while filtering
the exhaust
and providing one or more components designed to contain and/or retain the
dust within
the machine until such time as cleaning is desired.
[0300] With
reference to Figure 76, a cutting path 4000 of the grinding wheel
is shown with dashed lines. During translation of the grinding wheel along
this path
4000, metal shavings or grindings will be produced. As such swarf of the metal
shavings
or grindings will emanate from the grinding wheel. A swarf zone 4002 is
illustrated in
Figure 76 in chain line (i.e., dash-dot-dash). The swarf zone 4002 is a region
in which
most of the shavings or grindings will naturally fall.
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[0301] In some
configurations, one or more magnetic members 4004 can be
positioned within the inner compartment of the skate sharpener 1010. In some
configurations, the one or more magnetic members 4004 can be positioned on a
lower
portion of the inner compartment. In the illustrated configuration, the one or
more
magnetic members 4004 are positioned on or adjacent to a floor of the inner
compartment
of the skate sharpener 1010. In some configurations, the one or more magnetic
members
4004 is positioned within the swarf zone. In the illustrated configuration,
the one or more
magnetic members 4004 are positioned on or adjacent to the floor of the inner
compartment within the swarf zone 4002. In some configurations, the one or
more
magnetic members 4004 are positioned at least partially within, and/or at
least a portion
of the one or more magnetic members 4004 is positioned to within, a region
positioned
vertically below the cutting tool path 4000. These locations can position the
one or more
magnetic member 4004 in a location that will reduce the movement of the
shavings or
grindings and, therefore, provide a cleaner appearance to the skate sharpener.
In some
configurations, the one or more magnetic member 4004 is a cap that is
positioned at or
near the swarf that sprays out from the grinding wheel as the grinding wheel
sharpens the
skate blade. In some configurations, the cap captures between about 65% and
80% of the
metal dust generated in a sharpening operation. This capture of the dust helps
maintain a
tidier appearance and improves operation and life of a dust capture and/or
filtration
system 4010.
[0302] With
reference now to Figure 77, components of the dust capture
and/or filtration system 4010 that forms a portion of the skate sharpener 1010
will be
described. As illustrated, the skate sharpener 1010 can be provided with a
dust pan 4012.
The dust pan 4012 is sized and configured to cover much if not all of the
bottom or floor
of the compartment defined within the skate sharpener 1010. The dust pan 4012
includes
an outer lip 4014 and a recessed main region 4016. The outer lip 4014 can be a
single lip
that circumscribes the main region 4016 or can be a plurality of lips that can
be used to
support the dust pan 4012 in position within the sharpener.
[0303] As will be
described, in some configurations, the skate sharpener 1010
can be configured to not operate without the dust pan 4012 in positon within
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sharpener. For this reason, one or more switches 4018 can be provided. The lip
4014 can
bear against the switch 4018 such that the presence or absence of the dust pan
4012 can
be detected. Other configurations also can be used. In addition, the magnetic
member
4004 can be positioned on top of, underneath or within the dust pan 4012.
[0304] The
illustrated dust pan 4012 includes an upwardly embossed portion
4020. The upwardly embossed portion 4020 overlies an air filter assembly 4022.
As
illustrated, the air filter assembly 4022 comprises a base 4024 and a capture
ring 4026
that secure a filtration element 4028 in position. The filtration element 4028
can be any
desirable medium so long as the filtration element 4028 is able to trap and
retain dust
generated during operation of the skate sharpener 1010. In some
configurations, the
filtration element 4028 is a HEPA filter element.
[0305] As
illustrated, the base 4024 includes one or more internal ribs or other
structural features 4030 that hold the filtration element 4028 above a floor
of the air filter
assembly. Thus, the filtration element is positioned above an air flow exit
from the
illustrated air filter assembly 4022. Of course, other assemblies can be used
to filter
airflow through an air filter assembly.
[0306] The capture
ring 4026 overlies the filtration element 4028 and secures
the filtration element 4028 in position. In some configurations, the capture
ring 4028 is
pivotable about a rear portion and includes catches or the like to allow the
capture ring
4028 to squeeze on the outer periphery of the filtration element 4028. In some
configurations, a ring-like seal or the like can be positioned between the
base 4024 and
the filtration element 4028 such that air flow must pass through the
filtration element
4028 rather than bypassing the filtration element by passing between the base
4024 and
the filter element 4028. In some configurations, a sealing relationship or
assembly could
be established between the capture ring and the filter. Other configurations
also are
possible.
[0307] An exit 4032
is formed in one end of the air filter assembly 4022. The
exit 4032 leads upwardly into a blower 4034. The blower 4034 can have any
suitable
configuration. In the illustrated configuration, the airflow enters that a
central opening
4036 (see Figure 79) and exits through a tangentially oriented outlet 4038
(see Figure 78).
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Airflow exiting the outlet 4038 enters into an exhaust cavity 4040. The
exhaust cavity
4040 can be defined by an outer end cap 4042 of the skate sharpener 1010. The
exhaust
cavity 4040 also can be defined by one or more gaskets or seals 4042 to help
guide the
airflow to an exit 4044 from the skate sharpener 1010.
[0308]
Advantageously, the flow generated by the blower 4034 also can draw
airflow in though the opposite end of the skate sharpener 1010 to further aid
in cooling of
the stepper motor 1260, where present. Most of the flow into the air filter
assembly 4022
occurs either around the edges of the outer lip 4014 or through a small
carveout 4046 (see
Figure 76) provided to an outer perimeter of the dust pan 4012. The airflow
through
these two portions is adequate to provide both sufficient cooling flow as well
as sufficient
airflow through the filter.
Skate Sharpener Operation Control
[0309] As discussed
above, operation of the skate sharpener can be
interrupted or otherwise controlled based upon various sensed conditions. For
example,
when the switches of the slot covers indicate to the controller that the slot
covers are not
in position over the slot and adjacent to the skate blade or skate blade
holder, the
controller may interrupt power to one or more of the motors that drive the
grinding wheel.
[0310] Similarly,
as discussed above, the switch 4018 can be used to detect
the presence or absence of the dust pan 4012. When the dust pan is not
present, the
controller again may interrupt power to one or more of the motors that drive
the grinding
wheel. While not shown, a switch can be provided that indicates the presence
or absence
of the filter element. Again, operation of one or more of the motors that
drive the
grinding wheel can be interrupted if the filter element is not detected as
being present.
[0311] Further, as
shown in Figure 80, a front door switch 4050 can be
provided to the skate sharpener 1010. The front door switch can he used to
detect
whether the front door is open or closed. When the front door switch indicates
that the
front door is opened, the controller again may interrupt power to one or more
of the
motors that drive the grinding wheel. In some configurations, the front door
may be
latched shut such that it cannot open during operation of the sharpener.
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[0312] In some
configurations, the controller can be configured to detect the
absence or presence of a grinding wheel prior to initiation of a grinding
operation. In
some embodiments, the controller may determine whether the grinding wheel is
present
by detecting an identification tag 204 of the grinding wheel. When the
grinding wheel is
not present, the controller may interrupt power of one or more of the motors
that drive the
grinding wheel, or otherwise prevent initiation of a grinding operation.
[0313] In some
configurations, any or all of these operations can be performed
by something other than the controller. For example, the switches can,
themselves,
simply interrupt the power. In use, if any of the slot covers or door are not
in the
operating position, the skate sharpener will stop grinding or thwart the
initiation of a
grinding operation. Thus, the skate sharpener can provide improved operating
characteristics that result in the user obtaining the full benefit of each of
the designed in
features.
[0314] A soft start
routine for operational control of the skate sharpener can
be described with additional reference to Figures 4, 7, and 8. During the
grinding
operation, when the grinding wheel 36 makes first contact with the right edge
of the skate
blade 142, the grinding power goes from approximately zero to an elevated
state in a very
short period of time. The moment (e.g., torque) created at the interface
between the skate
blade 142 and grinding wheel 36 can push the control arm 78 upward (for
example,
further driving the grinding wheel into the skate) and can increase the
contact force at this
interface. When downward movement of the grinding wheel 36 occurs as it
traverses
along the skate blade 142, the grinding wheel 36 may bounce on the edge of the
skate
blade 142. The degree to which a bounce may occur can be affected by a number
of
factors, such as, for example, the position of contact of the grinding wheel
36 on the skate
blade 142, the steepness of the edge of the skate blade 142, the coarseness of
the grinding
wheel 36, the age of the grinding wheel (for example, newer grinding wheels
may have
more aggressive abrasive than used grinding wheels), and other factors. For
example, a
higher wheel position, steeper blade, and/or newer wheel may each contribute
to
increased bounce during contact. In some circumstances, bouncing of the
grinding wheel
36 may cause damage to components of the skate sharpener. The bouncing
behavior of
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the grinding wheel can result in non-uniform material removal and surface
finish of the
skate.
[0315] In some
embodiments, a soft start routine can be implemented to help
reduce bouncing when the grinding wheel 36 first contacts the skate blade 142.
Before the
grinding wheel 36 contacts the skate blade 142, the grinding wheel 36 travels
a distance
between the home position and the contact position of the skate blade 142.
Without a soft
start routine enabled, the grinding wheel 36 may rotate at full speed, for
example between
4000 rpm and 12000 rpm, and spin at roughly this rate for the complete
grinding
operation. In embodiments that implement a soft start routine, the grinding
motor 80 may
initially operate at a lower speed, such as 500 rpm to 3500 rpm until contact
is made with
the skate blade 142.
[0316] The soft
start routine can help to reduce bouncing when a grinding
wheel first contacts the skate blade. The soft start routine can help to
reduce the opposing
forces experienced between the grinding wheel 36 and the skate blade 142 at
the point of
first contact. By reducing grinding wheel RPM at the point of contact, the
grinding wheel
36 can experience reduced forces which help to reduce the downward movement of
the
motor arm 78 and reduce bouncing behavior. After contact is established
between
grinding wheel 36 and skate blade 142, the soft start routine can be
configured to ramp up
the speed of the grinding motor 80 to full speed, which can result in a smooth
translation
of the grinding wheel 36 during operation without bouncing. The soft start
routine can be
configured to help eliminate dangerous conditions associated with a grinding
ring 36
hitting a steep skate blade 142, which could be powerful enough to break one
or more
components of the sharpener or damage the skate blade 142. In some
embodiments, the
soft start routine can smooth the power consumption across the heel which can
result in
more even material removal rate on all sections of the skate.
[0317] Prior to
contact with the skate, the control system can monitor the
current drawn by the grinding motor and can establish a baseline current of
the system.
The baseline current represents the amount of current, and thus power, used by
the
grinding motor 80 prior to the grinding wheel 36 contacting the skate blade
142. The
baseline current can vary each time the skate sharpener is operated, during
grinding
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operations, and between different systems. Some factors that may contribute to
variations
in a baseline current can include, but is not limited to, slight differences
between motors
and in-part tolerances (such as, bearings of the grinding spindle),
temperatures of the
motor and spindle, wear of mechanical and electrical components, and/or other
factors
may influence variations in current. In some embodiments, the baseline current
can be
established over a period of between 0.5 seconds to 3 seconds. In some
embodiments, the
baseline current may be determined in less than one second, under two seconds,
under 3
seconds, or another time period. In some embodiments, baseline current
determination
may be delayed during initial startup (such as, a cold start) of the motor for
a defined
period of time in order for the system to arrive a steady state. The delay can
help to filter
out transient power fluctuations that may be experienced during start-up and
allow time
for the skate sharpener to attain a steady state of operation.
[0318] When the
grinding wheel makes contact with the skate, the grinding
motor 80 may naturally slow down due to the load applied to the grinding wheel
36 via
friction and resistance on the motor's output spindle 82. When the grinding
motor 80
slows down, the back EMF generated by the grinding motor 80 is reduced, which
results
in an increase in the current flowing to the grinding motor 80. The control
unit 32 of the
skate sharpener can monitor the current and can detect the increase in
current. The control
unit 32 can implement a threshold over the baseline current to determine
whether the
grinding wheel is in contact with the skate blade 142. The threshold can be a
percentage
of the baseline (such as, for example, a 10% increase of the baseline
current), a static
value (such as, for example, an increase of 200 mA over the baseline current),
a rate of
increase in the current (such as an increase of 200 mA in 0.1 seconds), and/or
other
threshold configured to detect contact between the grinding wheel and the
skate blade.
[0319] After
contact between the skate and the grinding wheel has been
detected, the control unit 32 can ramp the speed of the grinding motor 80 to a
higher
speed, which may be full speed in a relatively short period of time. For
example, in one
embodiment, the speed of the grinding wheel 36 may be increased from 1000 rpm
to
8000 rpm over a period of 0.55 seconds. The rotational speed of the grinding
wheel 36
may be controlled using various control algorithms, such as Pulse Width
Modulation
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(PWM) or other algorithms know in the art for controlling rotational speed of
an electric
motor. The ramp from the intermediate speed to full speed can use a linear,
exponential,
or other ramp algorithm configured to help reduce bounce while increasing
speed and
maintaining a smooth transition. The soft start routine can be implemented
using open
loop or closed loop control of ramp speed. The implementation of a soft start
routine is
not limited to the grinding motors described herein, and can be implemented
with various
types of electric motors that can be configured to modulate the speed of the
electric motor
[0320] In some
embodiments, the bounce experienced by the system can be
greater in one direction, for example moving from right to left or visa-versa.
When the
grinding wheel traverses over the left side (moving right to left or left to
right) of the
skate, the bounce can be significantly less because interface forces are
decreased at the
left side of the skate due to such factors as the direction of rotation,
location of the pivot
point, and the side of the grinding ring where frictional forces are
generated. When the
grinding wheel returns to its home position off the right edge of the skate,
the direction of
rotation of the grinding wheel causes an increase in the force driving the
grinding wheel
into the skate.
[0321] In some
embodiments, it can be beneficial for the soft start routine to
implement a lower grinding speed on the right edge (heel) of the skate. This
lower
grinding speed can result in a decrease in material removal rate on the right
to left pass
which can help neutralize the higher removal rate of material from the heel by
the
grinding wheel during the left to right pass. The result can be a more uniform
material
removal rate along the length of the skate. It should also be appreciated that
the soft start
routine can be used on the initial approach and contact with the skate blade
on either end
of the skate (e.g., right or left, heel or toe).
[0322] After the
grinding wheel returns to the home position, the soft start
routine can be reinitiated to allow the grinding motor to spin down to a lower
intermediate speed, in accordance with the operational parameters of the
grinding
operation, and repeat the soft start routine on a subsequent pass of the skate
blade 142.
The baseline current can be reestablished for each cycle in order to
compensate for
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possible changes in the baseline current. For example, the current to the
motor can change
as the motor and spindle heat up from use.
[0323] In some
embodiments, the control unit 32 can detect contact between
the grinding wheel 36 and the skate blade 142 using various alternative
methods and
systems. In some embodiments, an electrical proximity or contact sensor can
detect
contact between the skate blade 142 and grinding wheel 36. In some
embodiments, a
speed sensor (such as, for example, hall effect sensors, optical switches,
encoders, and the
like) can measure the grinding wheel 360 and/or motor speed to detect when the
speed of
the grinding wheel and/or motor reduces. In some embodiments, a tilt-sensor or
accelerometer mounted on the control arm 78 can detect when the control arm 78
starts to
move downward and/or detect vibration levels in the control arm 78. In some
embodiments, back EMF generated by the motor can be measured by sampling motor
voltage generation when spinning to determine when the back EMF decreases by a
threshold amount. In some embodiments, a torque sensor (e.g., piezo or strain
gauge) on
the motor output or grindinL, motor spindle shaft 82. The control unit 32 may
implement
one or more of the above contact detection systems in place of, or in addition
to, the
current baseline detection routine described above.
[0324] In some
embodiments, the control unit 32 can record the position of
the speed ramp up and can apply a similar ramp down when the grinding wheel is
returning to its home position off the trailing edge of the skate blade 142.
The ramp
down can help provide a more uniform grinding power and material removal rate.
In
some embodiments, a stepper motor can facilitate implementation of the ramp
down by
correlating the current sensing of the contact detection to a specific
location in the
grinding wheel travel. In some embodiments, an encoder can be used to detect
grinding
wheel position or an accelerometer to detect motor arm angle.
[0325] In some
embodiments, the soft start routine can also be used in an
algorithm to change the profile or "rocker" of a skate blade. Changing the
profile of a
skate can require inconsistent material removal along the skate edge to affect
the
lengthwise shape of the skate and thus the position of the skate over the
skate edge. The
soft start can correlate motor current information (or other motor power
measurements)
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with location along the length of the skate. The information gathered by the
soft start
routine can be used to selectively remove more or less skate material from a
given
segment of the blade.
[0326] In some
embodiments, the soft start routine can be used to increase
translation speed of the grinding wheel as compared to systems that do not use
a soft start
routine. For example, after the grinding wheel smoothly contacts the skate,
the rotational
speed of the grinding wheel 36 and the translation speed may be ramped up to
speeds
above what would be capable on a system using a uniform grinding speed during
the
grinding operation.
[0327] In some
embodiments, the soft start routine can adjust the speed to
account for the safe operation of grinding wheels having various grit levels.
Without a
soft start routine, a sharpening system may need to select a slower grinding
ring speed
based on the most aggressive grinding wheel that can be used with the system.
The soft
start routine can compensate for grinding rings of various grits by ramping up
to full
speed after smooth contact with the skate and without producing a potentially
destructive
bounce.
[0328] In some
embodiments, the soft start routine can be disabled. For
example, users of the sharpening system may use a skate type with the
sharpening system
that is not conducive to the Soft Start routine. In such situations, the user
may disable the
soft start routine in favor of sharpening at a constant grinding speed.
[0329] Figures 83
and 84 illustrate charts showing an example of power
consumed by a grinding motor during a grinding operation. The solid black line
illustrates
a pass of the grinding ring from the starting position on the right side of
the machine,
moving from right to left, from heel to toe ("moving left") without
implementation of a
soft start routine. The significant peak in the power consumed is visible at
the initiation
of the moving left pass. On the return pass, moving from left to right, from
toe to heel,
("moving right"), illustrated by the dash-dot line, there is another
characteristic peak
visible on the heel of the skate. The moving left pass utilizing the soft
start routine is
illustrated by the dashed line. The charts illustrates an example embodiment
of how the
soft start routine can change the power consumed during the grinding
operation. Figure
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84 additionally illustrates embodiments of the soft start "moving left" power
consumption
(dashed line), the "moving right" power consumption (dash-dot line), and an
average
power (solid line) consumed on the heel of the skate in both the "moving left"
and the
"moving right" passes. In this embodiment, the average power consumption seen
at the
heel is approximately equal to the power consumption seen across the skate
blade.
[0330] Figure 85 illustrates an embodiment of a flowchart for execution of a
soft
start routine 600. The routine 600 can be implemented by any system that can
dynamically control the speed of the grinding wheel within a skate sharpener.
The
routine 600, in whole or in part, can be implemented by the control unit 32,
controllers
132, and/or other hardware or software based control systems. Although any
number of
systems, in whole or in part, can implement the routine 600, to simplify
discussion, the
routine 600 will be described with respect to the control unit 32. Further,
although
embodiments of the routine 600 may be performed with respect to variations of
the
sharpening system, to simplify discussion, the routine 600 will be described
with respect
to the skate sharpener 10.
[0331] At block
602, the control unit 32 receives input to initiate a grinding
operation. The input may be received from an operator manually providing the
input by
pressing an input key, such as a start button. In some embodiments, the input
may be a
signal received from a remote source configured to initiate the operation of
the skate
sharpener.
[0332] At block
604, the control unit 32 begins operating the grinding motor
80 at a determined contact speed and begins translating the grinding wheel 36
toward the
skate blade 142 from the home position for execution of the grinding
operation. The
grinding motor 80 may initially operate at a contact speed, such as 500 rpm,
1000 rpm,
1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm and/or number between the
ranges.
The contact speed can be a lower speed than the operational grinding speed of
the
grinding operation. The grinding motor 80 can operate at the contact speed as
the
grinding wheel 36 travels a distance between the home position toward the
contact
position of the skate blade 142.
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[0333] At block
606, the control unit determines the baseline current of the
grinding motor 80 prior to contact with the skate blade 142. The control unit
32 can
monitor the current supplied to the grinding motor 80 and can determine a
baseline
current of the grinding motor 80. The baseline current represents the amount
of current
used by the grinding motor 80 prior to the grinding wheel 36 contacting the
skate blade
142. The baseline current can vary between skate sharpeners, between passes
during the
grinding operation, and between uses of the same skate sharpener. In some
embodiments,
the baseline current can be determined each time the grinding wheel executes a
pass of
grinding operation from the home position. In some embodiments, the baseline
current
can be established in less than 0.5, less than 1 second, less than 2 seconds,
less than 3
seconds, and/or within any combination of ranges of the above listed time
periods. In
some embodiments, such as during initial startup, the determination of the
baseline
current may be delayed for a defined period of time in order for the skate
sharpener to
reach steady state operation. Delaying the determination can help to filter
out transient
power fluctuations that may be experienced during start-up and prior to
attaining a steady
state of operation.
[0334] At block
608, the control unit can detect contact between the grinding
wheel 36 and the skate blade 142 based on an increase in current to the
grinding motor 80
over the baseline current by a threshold amount. When the grinding wheel 36
makes
contact with the skate, the grinding motor 80 may slow down due to the load
applied to
the grinding wheel 36 via friction and resistance on the motor's output
spindle 82. When
the motor 80 slows down, the back EMF generated by the motor 80 is reduced,
which
results in an increase in the current flowing to the motor. The control unit
32 can monitor
the current and detect when the current increases over a defined threshold.
The threshold
can be a percentage of the baseline (such as, for example, a 10% increase of
the baseline
current) or a static value (such as, for example, an increase of 200 mA over
the baseline
current).
[0335] At block
610, the control unit can increase the speed of the grinding
motor to an operational grinding speed. The operational grinding speed can be
greater
than 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, and/or any other speed greater
than the
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contact speed, as defined by the operational parameters of the grinding
operation. The
rotational speed of the grinding wheel 36 may be controlled using various
control
algorithms, such as Pulse Width Modulation (PWM) or other algorithms known in
the art
for controlling rotational speed of the grinding motor. The ramp from the
intermediate
speed to full speed can use a linear, exponential, or other ramping algorithm
to increase
speed while reducing bouncing of the grinding wheel on the skate. The increase
in
operational speed can be implemented in a relatively short amount of time. For
example,
in one embodiment, the speed of the grinding wheel may be increased from 1000
rpm to
8000 rpm over a period of 0.55 seconds. Operation of the grinding motor can be
implemented using open loop or closed loop control systems.
[0336] At block
612, the control unit continues execution of the grinding
operation in accordance with operational parameters until the grinding wheel
traverses to
the end stop of the skate sharpener. In some embodiments, the grinding
operation applies
a constant grinding force along the entire length of the skate. In some
embodiments, the
grinding operation may apply a varied grinding force along the length of the
skate. For
example, a grinding operation may be configured to alter the profile of the
skate. In such
an instance, non-uniform amounts of material are removed along the length of
the skate.
[0337] At block
614, the control unit continues execution of the grinding
operation in accordance with operational parameters until the grinding wheel
traverses
from the end stop to the home stop of the skate sharpener. In some
embodiments, the
bounce of the grinding wheel relative to the skate blade experienced by the
system can be
greater in one direction, for example moving from the home location to the end
of the
pass or visa-versa. In some embodiments, when the grinding wheel 36 traverses
from the
end location to the home location, the bounce can be significantly less
because interface
forces can be decreased on the end stop side of the skate due to factors, such
as the
direction of rotation of the grinding wheel 36, location of the pivot point,
and the side of
the grinding wheel 36 where frictional forces are generated. The rotational
speed of the
grinding wheel 36 can be the same in both directions. In some embodiments, the
rotational speed will be different for each direction in accordance with the
operational
parameters of the grinding routine. In some embodiments, the control unit 32
can apply a
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ramp down when the grinding wheel is returning to its home position off the
trailing edge
of the skate. The ramp down can help provide a more uniform grinding power and
material removal rate.
[0338] At block
616, after the grinding wheel returns to the home stop, the
control unit determines whether the grinding routine is complete. If the
grinding routine is
complete the process ends. If the grinding routine is not complete the process
returns to
block 604 to complete another pass. If another pass is going to be initiated,
the soft start
routine can be reinitiated to allow the grinding motor to spin down to a lower
intermediate speed, in accordance with the operational parameters of the
grinding
operation, and repeat the soft start routine on the subsequent pass. The
baseline current
can be reestablished for each cycle in order to compensate for possible
changes in the
baseline current.
[0339] In some
configurations, the door 30, 1030 can include a window 31,
1031 or the like. The window 31, 1031 can be a majority of the door 30, 1030
or can be a
small portion of the door 30, 1030. The window 31, 1031 provides light
transmissivity
between the inside and the outside of the skate sharpener 10, 1010. In some
configurations, the window 31, 1031 is transparent. In some configurations,
the window
31, 1031 is translucent. In some configurations, the window 31, 1031 is other
than
opaque.
[0340] Because of
the ability for light to be transmitted from inside of the
skate sharpener to outside of the skate sharpener, it is possible to provide a
general
indication of one or more states of operation of the sharpening system to the
user through
the window. For example, in some configurations, one or more light sources can
be
provided within the sharpening system. In one configuration, a multi-colored
light strip
can be provided just inside of the door. The light strip can be used to
indicate various
operating conditions of the sharpening system. For example, red can be used to
indicate
an error or a need for attention (e.g., slot covers not engaged with skate
blade or blade
holder), orange can be used to indicate a need for input into a user
interface, white can be
used to indicate that the door is open and green can be used to indicate that
a skate
sharpening process has been completed. Other indications can be used and other
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conditions also can be indicated. In some configurations, a flashing pattern
can be used
instead of discrete colors.
[0341] While
various embodiments of the invention have been particularly
shown and described, it will be understood by those skilled in the art that
various changes
in form and details may be made therein without departing from the spirit and
scope of
the invention as defined by the appended claims.
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