Note: Descriptions are shown in the official language in which they were submitted.
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LOG SAW CLAMP APPARATUS AND METHOD
FIELD OF THE INVENTION
This invention relates generally to clamping methods and apparatus. More
particularly, the invention relates to clamping methods and apparatus for
releasably securing
rolls of web material.
BACKGROUND OF THE INVENTION
Several web material products are initially produced in logs for ease of
manufacture.
As used herein and in the appended claims, the term "web" material refers to
any porous or
non-porous product which can be found in sheet form, regardless of length or
width.
Although the preferred embodiments of the present invention described below
are with
reference to operations performed upon webs of material made of any paper
product (which
includes without limitation paper toweling, toilet paper, napkins, tissues,
etc.), other
illustrative examples of web material products include foil, film, fabric,
cloth, cellophane,
wrapping paper, wax paper, etc.
A log is a rolled product of any web material having any set of dimensions. In
logs
of paper product web material, logs are generally sawed into smaller rolls to
be used by
consumers. Automation of the sawing process allows the manufacturer to achieve
satisfactory production rates. In many conventional log sawing devices, the
sawing process
generally involves a cutting blade, a clamp to hold the logs, and an advancing
mechanism to
move the logs.
Logs of paper product are often not very strong radially, and are typically
clamped to
provide support and to prevent the logs from being crushed by the saw. Such
logs are
preferably clamped on both sides of the blade to facilitate a straight cut
through the logs.
Most prior art clamps use elastic straps, flexible cylindrical strips, guide
troughs,
semi-cylindrical shells, or grippers to support a log during the sawing
process. Examples of
such conventional log clamping mechanisms are disclosed in United States
patent number
5,509,336 issued to Biagiotti, number 5,357,833 issued to Biagiotti, number
5,647,259
issued to Biagiotti, number 5,038,647 issued to Biagiotti, number 5,315,907
issued to
Biagiotti, and number 3,049,954 issued to Barlament et al., each of which are
incorporated
herein by reference insofar as they relate to log clamping mechanisms. Each of
these
clamping assemblies has one or more significant design limitations. Some
examples of
problems or limitations in the prior art devices include generally weaker
designs, speed
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limitations caused by inherently slower designs and frictional engagement,
excessive wear
and stress on parts, and complex assemblies requiring numerous parts.
Weaker log clamp designs typically result in clamps which are difficult to
adjust or
produce ineffective clamping results. Many prior art clamping devices allow
slight
movement during the clamping process which can cause bias cutting or product
flaws.
Because upstream equipment is usually capable of producing logs of varying
diameter, such
clamps should be manually or automatically adjustable to accommodate logs
having
different diameters. However, several prior art clamps are not easily
adjustable. Those prior
art clamps which are adjustable generally require extra tooling or screws to
set the clamps in
desired positions.
An example of problems arising with respect to clamp adjustability is found in
the
semi-cylindrical shell clamp disclosed in the Biagiotti '907 patent. This
clamp has one fixed
side and one spring-loaded resiliently mounted side. The spring-loaded
resiliently mounted
side requires the adjustment of small screws to alter the compression of the
spring and the
diameter of the clamp. This system of adjustment requires the operator to stop
the saw while
changing the setting because of the proximity of the screws to the saw.
Further, this semi-
cylindrical shell device can only accommodate slight changes in log diameter
due to the
small range of movement of the resiliently mounted side. Because there are
only two shells,
a large variation in the log diameter causes the edges of the shells to cut
into a larger log,
while a smaller log does not receive an adequate clamping force and clamp
forces would be
undesirably concentrated. Either one of these situations can cause product
flaws.
Another common design problem in the prior art involves vertical clamp
adjustment.
In most conventional log saws, the log is advanced on guides at a fixed
height. These
guides support the bottom of the log. When logs of varying diameter are passed
through the
system, the bottoms of the logs are each located at a constant height rather
than the centers of
the logs. Some prior art clamps can be adjusted to change the diameter of the
clamp while
keeping the center of the clamp unmoved. When the diameter of such a clamp is
adjusted,
the bottom of the clamp must move. Therefore, these clamps must be mounted to
move
vertically as well as radially to align the bottom of the clamp diameter with
the bottom of the
incoming log. This extra motion step makes adjustments more time consuming and
complicates the clamp design. An example of such design is disclosed in the
Biagiotti '336
patent.
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Most prior art clamps can be grouped into two general categories: constant
pressure
clamps and intermittent clamps. Constant pressure clamps use a spring or other
resilient
member to apply constant pressure on the log or to provide a resilient
restraining structure
about the log. Intermittent clamps only clamp the log during cutting
operations and then
release to allow the log to advance forward for the next cut. The intermittent
clamps
experience rapid cycle times between the clamp and release positions. This
constant cycling
creates two major problems: speed limitations and increased wear on parts.
Because the intermittent clamps must clamp the log for each cut and then
release the
log for advancement, the speed of the log saw is limited by the speed of the
clamp. Even
with rapid cycle times, log saws with intermittent clamps are slower than log
saws with
constant pressure clamps.
Due to the rapid cycle times of intermittent clamps, parts are exposed to wear
and
tear from constant rubbing. A prior art device that exhibits problems
resulting from
excessive wear and friction between parts is the flexible cylindrical strip
and elastic strap
clamp disclosed in the Biagiotti '833 patent. This clamp includes an elastic
belt that is
pulled down over two contacting strips with rapid cycle times to clamp the
logs. The
constant friction between the belt and the strips slows the clamp's adjustment
to different
diameter logs and can cause the belt to wear out.
In order to possess flexible properties, the strips must be relatively thin.
Due to the
thin construction of the strips, the strips are easily bent or damaged. The
flexible strips also
can suffer from plastic deformation and lose their resistive properties
because of the constant
cycling. These strips are especially likely to deflect when a hard log is
clamped. As a result
of the above limitations, these parts may need to be frequently replaced.
Another example of a prior art device which has wear and tear limitations is
the
gripper clamp disclosed in the Biagiotti '647 patent. In this clamp, a
reciprocating actuator
rotates an outer ring. Grippers are attached to the outer ring via pins which
fit into grooves
in the ring. When the ring rotates, the grooves force the pins and the
grippers back and forth.
The constant reciprocating wears down the contacting surfaces of the ring and
grippers.
Wear and tear on parts is closely related to the problem of overly complex
designs.
Several prior art devices include numerous small parts and assemblies which
are difficult to
access in the log clamp device. Also, these complex designs are relatively
expensive to
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manufacture, assemble, maintain, and repair. The deterioration of parts due to
friction and
wear creates significant maintenance problems of accessing small and often
concealed parts
and replacing them in close quarters. Replacing the parts is also time
consuming and
typically requires the log saw to be stopped while this maintenance is being
performed. The
inability to consistently run the log saw therefore costs the manufacturer a
significant amount
of money and increases machine inefficiency.
In light of the problems and limitations of the prior art described above, a
need exists
for a log saw clamp that is easily adjustable, substantially rigid, strong,
effectively clamps
the log, does not require that logs be slowed during cutting operations, has
relatively few
moving parts, does not have an overly complex design with small intricate
parts, has a design
permitting ease of manufacture and maintenance, is easy to adjust without
requiring system
shutdown, and which has a minimum number of moving parts subject to wear. Each
preferred embodiment of the present invention achieves one or more of these
results.
SUMMARY OF THE INVENTION
The log saw clamp device of the present invention includes at least one jaw
and a
brace. The jaw and brace are preferably both coupled to an actuation member.
Movement of
the actuation member thereby causes movement of the jaw and brace. The jaw is
preferably
mounted for rotation about a pivot point. Preferably, the jaw has a curved
side which
contours to the shape of the log and which provides for support of the log.
The jaw preferably includes a jaw mount and a jaw member. Preferably, the jaw
member is coupled to the jaw mount using a quick change connection and can be
interchanged with at least one other jaw of a different size to modify the
clamp for different
log types (e.g., logs having a significantly different diameter). A quick
change jaw is also
easier to replace when parts of the clamp assembly become worn or are damaged.
Movement of the actuation member can adjust the jaw to modify the clamp for
logs with a
moderately different diameter.
The actuation member is preferably moved by a turn wheel and gear assembly.
While many conventional assemblies and devices can be used to move the
actuation member
for adjusting the jaws, the turn wheel and gear system allows for precise
adjustments. The
turn wheel and gear system also permits adjustments to be made on the clamp
assembly
while the saw is performing cutting operations, thereby avoiding the need to
stop log sawing
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operations to adjust the clamp.
In the preferred embodiment, the clamp provides a constant clamping pressure
on the
logs and movement of the actuating member adjusts the diameter of the clamp.
Because the
clamp applies a constant pressure, the speed of the log saw is not limited by
the clamp (such
as in prior art intermittent clamps described above). However, the clamp can
easily be
modified for automatic cyclical movement of the actuating member which would
intermittently clamp the logs.
The brace is mounted for translation and can be mounted to the actuation
member for
movement with the actuation member and the jaws. Preferably, the brace has a
curved
surface to provide sufficient contact with the log as it moves through the
clamp. More
preferably, the brace is resiliently mounted with springs to accommodate
slight variations in
log diameters and to apply an adequate clamping force on the logs.
In operation of the present invention, linear movement of the actuation member
preferably causes rotational movement of the jaw and translational movement of
the brace to
increases or decrease the diameter of the clamp. The diameter of the clamp can
preferably be
adjusted while keeping a point on the circumference of the clamp relatively
constant. This
feature eliminates the need for vertical adjustment of the clamp because the
logs usually
enter the clamp with the bottom edge of the logs at a constant level
regardless of the logs
diameter.
The log saw clamp of the present invention has a robust design with relatively
few
small or moving parts. This substantially rigid design allows the clamp to
apply a higher
clamping force and makes the clamp more durable. Having fewer complex and
intricate
parts makes manufacture, assembly and maintenance easier.
Further objects and advantages of the present invention, together with the
organization and manner of operation thereof, will become apparent from the
following
detailed description of the invention when taken in conjunction with the
accompanying
drawings, wherein like elements have like numerals throughout the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is further described with reference to the accompanying
drawings, which show a preferred embodiment of the present invention. However,
it should
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be noted that the invention as disclosed in the accompanying drawings is
illustrated by way
of example only. The various elements and combinations of elements described
below and
illustrated in the drawings can be arranged and organized differently to
result in
embodiments which are still within the spirit and scope of the present
invention.
In the drawings, wherein like reference numerals indicate like parts:
FIG. 1 is a perspective view from below of a log saw clamp assembly according
to a
preferred embodiment of the present invention;
FIG. 2 is a front elevational view of the log saw clamp assembly shown in FIG.
l,
showing the log saw clamp in a fully opened position;
FIG. 3 is a front elevational view of the log saw clamp assembly shown in
FIGS. 1
and 2, showing the log saw clamp in a fully closed position; and
FIG. 4 is a side elevational view of the log saw clamp assembly shown in FIGS.
1-3.
DETAILED DESCRIPTION
A prefer ed embodiment of the log saw clamp assembly 10 of the present
invention
is illustrated in FIG. 1 as it would appear in a log saw apparatus. The
present invention can
be used with any conventional log saw device. One such log saw device is shown
(by way
of example only) in the figures. In the illustrated log saw device, logs are
conveyed to a
cutting position with respect to a log saw blade 14 via conventional log saw
guides 22 along
which run a chain 48 and a series of log saw fingers 50 having paddles 54 for
pushing the
logs. The chains 48 run around sprockets 46 at the ends of the log saw guides
22 to provide
for continuous passage of fingers 50 and paddles 54 along the guides. The
conveyor
assembly 18 defined by the log saw guides 22, the chain 48, the log saw
fingers 50, and the
paddles 54 is driven in by a conventional device such as a motor controlled by
a system
controller. For purposes of increasing the speed of product output, many
systems such as
that illustrated in the figures have multiple log lanes (limited at least in
part by the size of the
log saw blade 14) through which two or more logs pass and are cut
simultaneously.
However, systems having only one lane are also possible. The conveying
assemblies for the
lanes are typically of the same design and operate in the same manner. The
particular
conveying device employed does not form an important feature of the present
invention, and
as noted above, other well-known conveying devices and drives can be used with
the
invention. Such alternative conveying devices include without limitation belt
and pulley
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assemblies, slides, conveyor belt assemblies, and the like.
Because lateral forces are usually exerted upon each log as it is being cut by
the blade
14, it is generally necessary to restrain the log from movement during cutting
operations. To
this end, a log saw clamp according to the present invention is preferably
located on both
sides of the blade's cutting path, with a clearance therebetween adequate for
the blade 14 to
pass between the clamps and to cut the log therein. However, it is possible to
employ only
one such clamp on either side of the log saw blade.
The log saw clamp assembly 10 of the present invention includes an actuation
member 30, a brace 34, and at least one jaw 38 mounted for rotation about a
pivot 86 which
preferably supports the jaws 38 in the clamp assembly 10. The pivot 86 is
preferably
secured in a conventional fashion against movement with respect to the frame
of the
assembly (not shown), such as by one or more arms, braces, or frame members
(also not
shown) extending laterally from beside the jaws 38 and supporting the pivots
86 for rotation.
Preferably, there are two rotation jaws 38 for each brace 34 as illustrated in
the figures.
Other embodiments of the present invention can have only one jaw, one fixed
jaw (not
capable of rotation) and one jaw mounted for rotation, or any combination of
fixed and
rotatable jaws.
Although the jaw 38 can be a one-piece element, the jaw 38 is preferably made
of at
least two pieces and most preferably three pieces: a jaw mount 74 and one or
more jaw
members 26 (but most preferably two jaw members 26 as shown in the figures).
An
important feature of the present invention is the speed with which the jaw
members 26 can
be removed and replaced as will be discussed in more detail below. Therefore,
in preferred
embodiments of the present invention, the jaw members 26 are preferably
fastened to the jaw
mounts 74 by releasable fasteners such as threaded fasteners, pins, clamps,
and the like.
Most preferably however, the jaw members 26 are releasably attached to the jaw
mounts 74
via a number of bolts 36 passed through matching holes in the jaw members 26
and the jaw
mounts 74. To assist and speed the process of interchanging jaw members 26,
the jaw
mounts 74 and the jaw members 26 each preferably have a key and groove
connection (or
other quick release and connect mechanism) as indicated in FIGS. 2 and 3 by
reference
numeral 40 for positioning and aligning the jaw members 26 upon the jaw mounts
74.
The jaw member portion of the jaw 38 defines a surface which acts to restrain
the log
as it is being cut by the saw blade 14. Preferably, the jaw member 26 is
therefore an
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elongated body which has a concave surface facing the log being cut, and runs
substantially
the entire length of the clamp assembly 10. Alternatively, this surface can be
virtually any
shape desired, such as flat, ribbed, mufti-sided, V-shaped, or even concave
(in which case
each jaw member 26 would likely contact the log along one longitudinal line
during cutting
operations). Similarly, the elongated shape of the jaw member 26 can be
shortened or
lengthened considerably to produce a more compact or longer clamp as desired.
The
elongated concave surface illustrated in the figures is preferred because it
provides support
for the log while in the clamp (when the jaw member 26 at least partially
supports the log in
the clamp as discussed below) and provides a substantial and smooth contact
with the log
being cut. The jaw members 26 are preferably made from a rigid or
substantially rigid
material such as aluminum, steel, iron, or other metal, composites, plastic,
and the like.
However, the jaw members 26 can be made from semi-rigid material to permit
slight
deformation under pressure or impact, such as from the log during cutting
operations. These
semi-rigid materials include without limitation rubber, urethane, and other
synthetic
materials.
To control the jaw member 26 at both ends, the jaw 38 preferably has a jaw
mount 74
attached to or depending from each end of the jaw member 26. Each jaw mount 74
is
attached to a respective actuation member 30 via a pin 78 as can best be seen
in FIG. 1. The
jaw mounts 74 are preferably elongated in shape as shown in the figures,
thereby providing a
torque arm against which force can be exerted to pivot the jaws 38 about the
pivots 86.
However, it should be noted that the jaw mounts 74 can be virtually any shape
having a
portion which is located a sufficient distance from the jaw member 26 for an
applied torque
to pivot the jaws 38. With reference to FIGS. 2 and 3, it can be seen that
when the jaws 38
are pivoted about the pivots 86, the jaw members 26 are moved toward and away
from an
area 110 into which logs are received for cutting. The log receiving area 110
is an area
which is at least partly bounded by the jaw members 26 and the brace 34. By
pivoting in this
manner, the jaw members 26 have a component of movement which is radial with
respect to
the log receiving area 110 and the axis 12 therein and a component of movement
which is
tangential with respect to the log receiving area 110 and the axis 12.
Therefore, the jaw
members 26 preferably each follow a substantially arcuate path of motion
toward and away
from the log receiving area 110 and the axis 12 when the jaw members 26 are
pivoted as just
described. Because the jaw member 26 preferably face each other and are
pivoted toward
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one another in their movement, the paths of the jaw members 26 converge toward
the log
receiving area 110 and the axis 12 as the clamp assembly 10 is tightened
(described in more
detail below).
The brace 34 of the present invention is mounted adjacent to the jaws 38 (and
more
specifically, adjacent to the jaw members 26) as shown in FIGS 1-3. Like the
jaw members
26, the brace 34 preferably extends substantially the entire length of the
clamp assembly 10
and preferably has a convex curved surface facing logs in the log receiving
area 110. The
brace 34 can instead present a straight or substantially straight surface to
logs in the log
receiving area 110, and can take any of the surface shapes discussed above
with reference to
the jaw members 26. The brace 34 is preferably made of metal, and is more
preferably made
of aluminum, but can be made of any material discussed above with reference to
the jaw
members 26.
Where multiple lane log saw systems are used as shown in the figures, the
brace 34
preferably extends as a one-piece element across adjacent log saw clamp
assemblies 10.
However, dedicated braces 34 for each lane can instead be employed if desired.
The brace 34 is preferably mounted within the clamp assembly 10 by a number of
clamp rods 58 attached to the brace 34. The clamp rods 58 can be rigidly
attached to the
brace 34 in a number of conventional manners, such as by being welded, bolted,
press fitted,
and the like. However, the clamp rods 58 are more preferably received within
apertures 60
in the brace 34, with end portions 66 of the clamp rods 58 having a slightly
smaller diameter
and being capped or fitted with nuts 70 to hold the brace 34 upon the clamp
rods 58. Most
preferably, conventional springs 42 are fitted upon the end portions 66 of the
clamp rods 58
and are located between the brace 34 and a shoulders on the clamp rods 58 to
exert a spring-
biased force against the brace 34 for limited movement of the brace 34 along
the clamp rods
58. Other embodiments of the present invention have a spring 42 or other
resilient material
on both sides of the brace 34. The ability of the brace 34 to move under
spring force in this
manner is desirable particularly when logs of slightly varying diameter are
passed into the
log receiving area 110, in which case slightly larger diameter logs will still
be admitted into
the log receiving area 110. One having ordinary skill in the art will
appreciate that many
other conventional springs and spring-loaded assemblies are capable of
providing the biasing
spring force just discussed.
In alternate embodiments of the present invention, the clamp rods 58 can be
replaced
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by a number of other elements capable of supporting the brace 34 in position
beside the jaws
38. For example, the clamp rods 58 can instead be plates, bars, tubes, or
other elements
extending from the brace 34 to the actuation member 30 and connected to each
in a
conventional manner. However, such alternative embodiments still preferably
have spring-
loaded assemblies as described above and most preferably have members which
extend
through the brace plate and which are spring loaded in a similar manner as the
clamp rods 58
of the illustrated preferred embodiment.
The clamp rods 58 are preferably movable (as will be discussed in more detail
below) to translate the brace 34 toward and away from the jaws 38.
Accordingly, and with
reference to FIGS. 2 and 3, the jaws 38 and the brace 34 together define the
log receiving
area 110 and act to restrain logs being cut from movement outside of the log
receiving area
110. Because the brace 34 is movable substantially upward and downward via
movement of
the clamp rods 58, and because the jaws 38 are pivotable toward and away from
the log
receiving area, the brace 34 and the jaws 38 can be placed in a range of
positions from a wide
position as shown in FIG. 2 (with the jaws 38 rotated apart and the brace 34
translated away
from the jaws 38) to a tightened position as shown in FIG. 3 (with the jaws 38
rotated
together and the brace 34 translated toward the jaws 38). The preferred manner
in which the
motion and positioning of these parts is created will now be discussed.
To provide a simplified log clamp design, movement of the brace 34 via the
clamp
rods 58 and movement of the jaws 38 are preferably accomplished by the same
element or
mechanism. In the preferred embodiment of the present invention illustrated in
the figures,
this is performed by movement of the actuation members 30. The actuation
members 30 are
preferably plates, panels, or like elements to which are attached the clamp
rods 58 and the
jaws 38. The clamp rods 58 are preferably attached in a conventional manner to
opposite
sides or edges of the actuation members 30, such as by bolts, screws, or other
threaded
fasteners, by welding, brazing, gluing, etc. Most preferably, bolts 72 are
passed through
apertures in the clamp rods 58 and into matching threaded apertures in the
actuation
members 30. The jaws 38 are preferably attached to the actuation members 30
via pins 78
extending from the actuation members 30 and into elongated apertures 82 in the
jaws 38 (and
more preferably in the ends of the jaw mounts 74 located a distance from the
pivots 86).
The actuation members 30 are preferably slidable along guides 114 flanking the
actuation members 30. The guides 114 can take many forms for a sliding,
gliding, or rolling
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relationship with the actuation members 30. For example, the guides 114 can be
C-shaped
rails into which the edges of the actuation members 30 are slidable received
or into which
pins, posts, or extensions of the actuation members 30 are slidably received
as shown in the
figures, a bearing track into which the actuation members 30 are mounted for
rolling
movement along the bearing track, rods or bars telescopingly received within
apertures of the
actuation members 30 running along the length of the actuation members 30,
etc.
Where multiple lane log saw systems are used as shown in the figures, the
actuation
members 30 preferably extend as one-piece elements across adjacent log saw
clamp
assemblies 10. However, dedicated actuation members 30 for each lane can
instead be
employed if desired. In such case, guides similar to those described
preferably flank each
actuation member in the same or similar manner to the guides 114 flanking the
two lane
system illustrated in the figures.
The elongated apertures 82 in the jaws 38 are preferably slanted with respect
to the
path of motion of the actuation members 30 as shown in the figures. As the
actuation
members 30 are moved along the guides 114, the pins 78 ride against the
opposing surfaces
84 of the elongated apertures 82 and thereby cause the jaws 38 to pivot about
their pivots 86.
By moving the actuation members 30 along the guides 114, the clamp rods 58 and
the brace 34 attached thereto translate toward or away from the jaws 38 while
the jaws 38
pivot toward or away from one another about their pivots 86. Therefore, such
movement of
the actuation members 30 tightens or loosens the clamp assembly 10 for
accommodating
logs of different diameters. As described above, the path of motion of the
jaws 38 is
preferably arcuate, having a component of motion which is radial and a
component of
motion which is tangential with respect to the log receiving area 110 and the
axis 12
therethrough. The jaws 38 of the clamp assembly 10 preferably converge toward
one
another along their arcuate paths as the clamp assembly 10 is tightened.
It will be appreciated by one having ordinary skill in the art that the
actuation
members 30 can take a number of forms also capable of moving the pins 78 as
described for
rotating the jaws 38 while translating the clamp rods 58 and the brace 34. For
example, the
actuation members 30 can be plates as illustrated in the figures, rods or bars
extending
between the guides 114 and mounted for movement in the guides 114, or even
fingers
secured to and extending laterally from the clamp rods 58 (in which case the
fingers can have
bent ends which serve the same functions as the pins 78 riding within the
elongated apertures
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82 of the jaws 38). Such alternative elements serve the same functions as the
plate-shaped
actuation member 30 described above and illustrated in the figures.
Although the jaws 38 are preferably pivoted by caroming motion of the
actuation
member pins 78 within the elongated apertures 82, the jaws 38 can be pivoted
in a number of
different manners. For example, rather than a set of pins 78 riding within
elongated
apertures 82 of the jaws 38, the jaws 38 can have pins riding within grooves
in the actuation
members 30. Alternatively, pins or cam followers extending from the actuator
members 30
can ride alongside the dogleg portions of the jaws 38 shown in the figures,
thereby guiding
the jaws 38 between the pins to rotate the jaws as the actuator members 30 are
moved. In yet
another alternative embodiment, the actuation member 30 shown in the figures
can have a
raised portion in the form of a wedge between the dogleg portions of the jaws
38, whereby
movement of the actuation member 30 in one direction causes the wedge to force
the jaws 38
apart, while movement of the actuation member 30 in an opposite direction
permits the jaws
38 to return to their positions shown in FIG. 2 by (for example) spring force
from springs
connecting pairs of jaws 38 together. Many other alternative devices and
assemblies exist
for pivoting the jaws 38 about their pivots 86, each of which preferably
simultaneously
moves the clamp rods 58 to translate the brace 34. Also, these alternative
devices and
assemblies need not necessarily rely upon caroming contact between the
actuation members
30 and the jaws 38 as is the case with the embodiments just described. Such
alternative
devices and assemblies fall within the spirit and scope of the present
invention.
It should be noted that still other alternative devices and assemblies can be
used for
pivoting the jaws 38 about their pivots but which do not simultaneously move
the clamp rods
58. For example, the clamp rods 58 need not necessarily be attached to the
actuation
member 30 for movement therewith, and can instead be mounted to a frame of the
system.
The actuation member 30 can then be a bar located immediately beneath the jaws
having a
wedge shape or ramped surfaces riding against the jaws 38 in movement of the
actuation
member 30 to push the jaws 38 apart under spring force as described above.
Alternatively,
the jaws 38 can ride upon pins attached to the clamp rods and laterally
extending within
elongated apertures 82 in the jaws 38, in which case a bar or other element
located
immediately beneath the jaws 38 and riding within the guides 114 can be
movable to push
the jaws 38 upward in FIGS. 2 and 3 to pivot about the pivots 86 while riding
upon the pins.
Downward movement of the bar would permit the jaws 38 to fall under gravity to
their
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13
positions shown in FIG. 2. While not preferred due to the lack of brace
movement for a
better enclosed log receiving area 110, these alternate embodiments also fall
within the spirit
and scope of the present invention.
A number of different devices and systems exist for moving the actuation
member 30
as described above (preferably within guides 114). In the preferred embodiment
of the
present invention, the actuation element 30 is adjusted via a turn wheel 90
which preferably
has a gauge or counter for a user to identify the diameter at which the log
clamp assembly 10
is set. The turn wheel 90 is preferably connected to the actuation element 30
through a
gearing assembly 94. In this assembly, turning the turn wheel 90 moves the
actuation
element 30 through the range of positions between a loose position as shown in
FIG. 2 and a
tight position as shown in FIG. 2. In particular, bevel gears turned by the
turn wheel 90
transmit rotational motion to a threaded rod 106 received within a threaded
hole 102 in the
actuation member 30 (or in an internally-threaded member attached in a
conventional fashion
to the actuation member 30). Such an assembly permits a user to precisely
position the
actuation member 30 at desired heights, and thereby to precisely position the
jaws 38 and
brace 34 in a range of clamping positions between and including the positions
shown in
FIGS. 2 and 3. The gear assembly 94 illustrated can be driven manually or
automatically via
a motor preferably connected to a controller.
One having ordinary skill in the art will recognize that many alternative
systems can
be used to adjust the position of the actuation member 30 for tightening and
loosening the
clamp assembly 10. For example, the actuation member 30 and attached clamp
rods 58 can
be moved by one or more electronic, hydraulic, pneumatic, or other actuators
attached to the
actuation member 30 or clamp rods 58 to exert motive force of the actuation
member 30 or
clamp rods 58, can be moved by a chain and sprocket or belt and pulley
assembly attached to
and alongside the actuation member 30 or clamp rods 58, etc. Any of these
alternative
systems can be operated by hand, but are preferably operated automatically via
a controller.
Due to the simplicity of the clamp design, the clamp assembly 10 can be
actuated (i.e., the
actuation member 30 and clamp rods 58 moved up or down) very quickly.
Therefore, the
clamp assembly 10 can be used as a constant pressure clamp or as in
intermittent clamp in
which a controller rapidly actuates the clamp assembly 10 to open and close
with each cut
made in a log. Although it is most desirable to employ one gear assembly for
moving the
actuation members 30 and the clamp rods 58 together, alternative assemblies in
which the
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14
clamp rods 58 are not secured to the actuation members 30 and/or are movable
independently of the actuation members 30 can employ different gear assemblies
for the
actuation members 30 and the clamp rods 58. Such a design permits greater
control over the
clamp assembly 10 in that it permits a user to separately adjust the positions
of the brace 34
and the jaws 38. As mentioned above, other well-known height adjustment
devices and
assemblies can be used for adjusting the clamp rods 58 and for adjusting the
actuation
members 30 in lieu of the gear assembly design illustrated in the figures.
In FIGS. 2 and 3, a gear assembly 94 is shown located only on one side of the
actuation member 30. Additional gear assemblies 94 (or other such devices and
assemblies
capable of moving the actuation member as discussed above) can be connected to
other parts
of the actuation member 30 and the clamp rods 58 to assist in actuation member
movement -
particularly for larger or heavier clamp assemblies. Where multiple lane log
saw systems are
used and have separate and dedicated actuation members 30 for each lane, each
lane can be
provided with a gear assembly or other moving device or assembly.
FIGS. 2 and 3 demonstrate one example of turn wheel location in the log clamp
assembly 10. In these figures, the turn wheel 90 is shown located at the level
of the gear
assembly 94. FIG. 4 demonstrates another location of the turn wheel 90, in
which the tum
wheel 90 is located at a higher point by being connected to the gear assembly
94 via a turn
shaft 98. Because log saw devices are typically mounted close to floor level,
the location of
the turn wheel 90 shown in FIG. 4 is preferred. The shaft 98 serves the
purpose of moving
the turn wheel 90 to a more convenient location for adjustment.
Preferably, the operator or controller adjusts the clamp assembly 10 to the
proper
diameter, such as by using the turn wheel 90. When the jaws 38 are rotated and
the brace 34
is translated to tighten the clamp assembly 10, the jaws 38 rotate and the
brace 34 translates
toward a reference line or axis 12 of the clamp 10 running parallel to the log
receiving area
110 (see FIGS. 2 and 3). The reference line or axis 12 is referred to herein
and in the
appended claims only for ease of device description, and does not imply that
the reference
line or axis is necessarily at a center point of the log receiving area or
that it necessarily
remains stationary (e.g., a set distance from the log saw guides 22) through
the adjustment
range of the clamp assembly 10. The reference line or axis 12 simply refers to
a line in the
log receiving area 110 which is substantially parallel to logs received in the
clamp assembly
10. The spring loaded brace 34 applies an adequate force to hold logs entering
and being cut
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within the log receiving area 110 relatively steady, yet enables log
advancement. The
conveyor assembly 18 preferably advances each log into the log receiving area
110 at a
nearly constant speed. Because the clamp assembly 10 of the present invention
can be
adjusted without stopping cutting operations, the clamp assembly 10 can be
adjusted
between runs of logs having the same diameter or can be adjusted each time a
cut made on
the log. Also, the clamp assembly 10 can be adjusted to leave a slight
clearance between the
jaws 38, the brace 34, and the log surface, or can be adjusted to exert a
clamping force upon
the log during each cut.
The embodiments described above and illustrated in the drawings are presented
by
way of example only and are not intended as a limitation upon the concepts and
principles
of the present invention. As such, it will be appreciated by one having
ordinary skill in the
art that various changes in the elements and their configuration and
arrangement are
possible without departing from the spirit and scope of the present invention
as set forth in
the appended claims.
For example, the log saw clamp assembly 10 is preferably oriented in the
manner
illustrated in the figures. However, the log saw clamp assembly 10 can be
arranged in
almost any orientation, such as upside down and sideways with reference to the
figures. The
log saw clamp assembly 10 can even be mounted so that logs pass horizontally
through the
system or vertically. Therefore, the jaws 38 of the assembly 10 need not
physically support
the logs therein, depending upon the particular orientation of the jaws with
respect to ground
(i.e., if the assembly 10 were upside down, the brace 34 would support the
weight of the log
in the assembly).
Although a jaw 38 running substantially the entire length of the clamp
assembly 10 is
preferred, this feature is not a requirement to practice the present
invention. Specifically, the
wedge-shaped jaw members 26 of the jaws 38 can be replaced by a separate jaw
member for
each jaw, in which case the front jaws shown in FIGS. 1 and 4 would have a
pair or jaw
members and the rear jaws would have their own pair of jaw members. The two
jaws 38 for
each clamp assembly 10 of the preferred embodiments would be effectively
replaced by two
front jaws and two rear jaws for each clamp assembly 10. Such a design permits
jaws to be
used which are much shorter than the elongated jaws illustrated in the
figures, but at the cost
of somewhat less support and stability for logs within the assembly.
As mentioned above, each jaw 38 is preferably made of two elements: a jaw
member
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26 and a jaw mount 74. In highly preferred embodiments of the present
invention, the jaw
members 26 are removable from the jaw mounts 74 by a user. The connection
between each
jaw member 26 and its respective jaw mount 74 is therefore preferably via any
type of
conventional releasable fastener. For example, the pivots 86 can be removable
to disconnect
the jaw mounts from the jaw members 26. These pivots 86 can be used alone or
in
combination with other removable fasteners (such as threaded fasteners, pins,
and the like
passing through the jaw mounts 74 and the jaw members 26). By permitting
removal of the
jaw members 26, a user can replace the jaw members 26 with one of a series of
jaw members
26 having different shapes, such as jaw members having different radii of
curvature to better
match logs to be run through the assembly. The other jaw members 26 can have a
variety of
different shapes and surfaces to accomplish different tasks or to better suit
different types of
logs being cut. Certain jaw members 26 can be better suited for clamping logs
of synthetic
material, for exerting higher gripping force against the logs, for handling
logs having varying
sensitivity to scuffing or damage, or for increased or decreased deformation
during clamping
if desired.
For the same proposes as just described, preferred embodiments of the present
invention permit the user to remove and replace the brace 34 with braces of
different shape
and size. Accordingly, the brace 34 is preferably secured to the ends of the
clamp rods 58
via removable nuts or other conventional removable fastening elements capable
of securing
the brace 34 in place upon the clamp rods 58.
As indicated above, the present invention is not limited to embodiments in
which two
rotatable jaws and one brace act to clamp logs in the log receiving area.
Although the two-
jaw system is preferred (particularly in light of the conveyor assembly
arrangement where
paddles 54 extend between the jaws 38 and into the log receiving area 110),
other conveyor
assembly designs permit different jaw and brace arrangements. For example, in
one jaw
clamp, the brace 34 preferably encircles the log receiving area 110 more fully
than shown in
the figures, such as three-quarters or two-thirds around the log receiving
area 110, with the
jaw 38 extending around the remainder of the log receiving area 110. In
another
embodiment, three, four, or even more jaws 38 are located about the
circumference of the log
receiving area 110, and can occupy more or less of the circumference of the
log receiving
area 110 as desired. In yet another embodiment of the present invention, the
brace 34 can be
made of two or more sections which can be separated from one another, located
in different
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17
locations about the circumference of the log receiving area 110, and even be
separated from
one another by one or more jaws 38. In short, although a one-piece brace and
two jaw clamp
assembly is preferred, alternative embodiments can employ more braces or brace
sections
and can have one, three, or more jaws moving with respect to the braces) in
the manner
described above to clamp and unclamp logs in the log receiving area 110. In
all such cases,
the jaws 38 preferably operate via rotation and the braces) 34 preferably
operate via
translation in the manners described above with respect to the preferred
embodiments of the
present invention. It should also be noted that where multiple jaws 38 are
employed, the
jaws 38 need not be of the same size or shape, nor need they occupy the same
amount of
circumference about the log receiving area 110. This is true also for those
embodiments of
the present invention in which multiple braces or brace sections are used.
