Note: Descriptions are shown in the official language in which they were submitted.
CA 02353236 2001-07-18
Attorneys' Ref.: P213139
ADJUSTABLE MOBILE MACHINE BASE
SYSTEMS AND METHODS
RELATED APPLICATION
This application is related in part to Canadian Patent File No.
2,267,043 filed March 26, 1999 and entitled "Adjustable Mobile
Machine Base Systems and Methods".
FIELD OF THE INVENTION
The present invention relates to mobile machine bases and, more
specifically, to mobile machine bases that are adjustable to accommodate
different machinery configurations.
BACKGROUND OF THE INVENTION
Machinery such as table saws, band saws, jointers, shapers, planers,
sanders, and the like should be stationary during use. In many cases, this
type
of machinery is permanently installed at a predetermined location in a shop.
Such machinery is thus commonly sold with a stationary base having feet that
frictionally engage the floor to maintain the machinery at the predetermined
location.
But in many situations it is desirable to move this type of machinery
between uses. For example, a user may have limited shop space, and may want
to store the machinery at a relatively inaccessible location when not in use
and
then, immediately prior to use, move the machinery to a more accessible
location. Or the user may wish to use the machinery at a job site. In this
case,
movement of the machinery from one location to another at the job site may be
desirable.
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Accordingly, mobile machine bases are often sold as an accessory to fit
under the stationary bases originally sold with shop machinery. Mobile bases
further comprise a locking system that allows the machinery to be rolled from
one
location to another between uses yet immobilizes the machinery during use.
More specifically, conventional mobile machine bases comprise a
relatively rigid frame assembly to which a plurality of wheel assemblies are
attached. The stationary base is removed from the bottom of the machine, and
the bottom of the machine is then bolted or otherwise rigidly attached to the
frame assembly. Usually, the iocking system employs a lock member that moves
between a locked position and an unlocked position. When in the locked
position, the lock member immobilizes the machinery by frictionally engaging
either the wheels or the floor surface to substantially prevent relative
movement
between the frame assembly and the floor surface. When in the unlocked
position, the lock member does not inhibit movement of the frame assembly
relative to the floor surface.
Machinery of the type rendered movable by the mobile machine base of
the present invention exists in a variety of shapes, sizes, and weights.
Currently,
manufacturers sell the mobile machine bases in a variety of configurations;
the
user selects one of these base configurations as appropriate for a given
machine
configuration.
What will be referred to herein as the "effective footprint" of the machine
determines which base configuration should be selected. The effective
footprint
is normally defined as the outside width and depth dimensions of the bottom of
the machinery. The configuration of the mobile base is defined by similar
width
and depth dimensions that should be just slightly larger than the width and
depth
dimensions of the effective footprint.
Requiring a base configuration for each effective footprint mandates a
production and distribution system in which the manufacturer must design,
build,
and keep in inventory a plurality of base configurations. The retailers must
similarly keep in stock at least the most popular, and preferably all, of
these
configurations. And the retailer's representative must have some expertise to
advise the customer on the right base configuration for a required effective
footprint. The result is an inefficient system that is labor and capital
intensive.
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Even then, it would be difficult to provide machine bases for all machines on
the
market. The need thus exists for a single machine base configuration that can
accommodate a number of effective footprints.
Another drawback of conventional machine bases is the locking system
used. Some of these locking systems employ a lock member that, in the locked
position, bears directly on the wheel to prevent rotation of the wheel. This
causes excessive wear on the wheel. Other locking systems require tools to
operate the locking system. The need thus exists for a machine base having
improved locking systems that do not cause excessive wheel wear or require
tools to operate.
Conventional machine bases further employ rigid frame assemblies that
cause the machine base to occupy a relatively large volume during
transportation
and storage. The need thus exists for a machine base that occupies a smaller
volume when not in use.
PRIOR ART
The Applicant is aware of a number of machine bases that are currently
on the market.
The assignee of the present invention currently manufactures and sells a
line of machine bases specially designed to fit the assignee's machinery but
will
also accommodate many machines manufactured by others. Each of the
assignee's machine bases is specially constructed for a given effective
footprint
and thus a number of individual designs are required. The locking system bears
directly on the wheel and thus can cause excessive wear over time.
HTC Products, Inc. and Delta each manufacture and sell a line of
machine bases. The bases sold by each of these manufacturers are each
designed for a specific effective footprint and thus suffer the problems
described
above associated with designing, building, keeping in inventory, distributing,
and
retailing a large number of separate base designs.
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SUMMARY OF THE INVENTION
From the foregoing, it should be clear that the present invention seeks
to provide an improved mobile base system for use on machinery such as table
saws, band saws, jointers, shapers, planers, sanders, and the like.
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These and other aspects are obtained by the present invention, which is
locking system for a mobile machine base. The exemplary locking system
comprises
at least one stop or lock member that may be fixed relative to the base such
that the
lock member frictionally engages the floor surface and prevents movement of
the
machinery.
In particular, a stop assembly of the present invention comprises a lock
housing, a lock member, a drive member, and a magnetic portion. The lock
housing
defines a lock chamber and is rigidly attached to the frame of the base.
The lock member is slideably mounted within the lock chamber of the lock
housing such that the lock member moves between an unlocked position in which
the
lock member does not engage the floor surface and a locked position in which
the
lock member frictionally engages the floor surface.
The drive member engages the lock housing such that rotation of the
drive member causes the drive member to move towards or away from the floor
surface. The drive member is at least partly located within the lock chamber
above
the lock member and is capable of rotating with respect to the lock member.
The magnetic portion is formed on one of the lock member and the
drive member such that upward movement of the drive member causes upward
movement of the lock member without inhibiting the ability of the drive member
to
rotate relative to the lock member.
The exemplary stop system disclosed herein comprises two such stop
assemblies.
Other aspects of the present invention will be apparent from the following
detailed description.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a mobile machine base of the present
invention being used to support a planer at a desired location on a floor
surface;
FIG. 2 is a top plan view of the mobile machine base shown in FIG. 1;
FIG. 3 is a side elevational view depicting the mobile machine base of
FIG. 1;
FIG. 4 is a top plan view showing the mobile machine base of FIG. 1 in a
different configuration from that shown in FIG. 1;
FIG. 5 is a section view taken along lines 5-5 in FIG. 2;
FIGS. 6-8 are section views taken along lines 6-6 in FIG. 2 that show the
operation of one of the assemblies forming the lock system used by the mobile
machine base of FIG. 1;
FIG. 9 is a side elevational view depicting the mobile machine base of a
second embodiment of the present invention;
FIG. 10 is a top plan view of the mobile machine base shown in FIG. 9;
FIG. 11 is a section view taken along lines 11-11 in FIG. 10;
FIG. 12 is front elevation section view depicting a locking assembly that
may be used in place of the lock systems depicted in FIGS. 6-8; and
FIG. 13 is an exploded front elevation view of the locking assembly of
FIG. 12.
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DETAILED DESCRIPTION
Referring now to FIG. 1, depicted at 20 therein is a mobile machine base
constructed in accordance with, and embodying the principles of the present
invention. The mobile machine base 20 is shown supporting a machine 21,
which in this case is a planer. The machine 21 is relevant to the present
invention only in that it defines an effective footprint having a width
dimension W,
and depth dimension D,.
FIG. 1 shows that the mobile machine base 20 comprises a frame
assembly 22, front and rear wheel assemblies 24 and 26, and a locking system
28 comprising first and second locking assemblies 30 and 32.
Referring now to FIG. 2, it can be seen that the frame assembly 22
comprises first, second, third, and fourth corner members 34, 36, 38, and 40
and
first, second, third, and fourth side members 42, 44, 46, and 48. The frame
assembly further comprises a plurality of screw members 50 that join the
corner
members 34-40 to the side members 42-48.
The corner members 34-40 are identical to each other; similarly, the side
members 42-48 are identical to each other. Accordingly, only the first corner
member 34 and first side member 42 will be described herein in detail.
The corner member 34 comprises first and second tube members 52 and
54. The tube member 52 has a distal end 56 and a proximal end 58; the second
tube member 54 similarly defines a distal end 60 and a proximal end 62. The
distal end 56 and 60 are cut at a 90 angle relative to the center axis of the
tube
members 52 and 54. The proximal ends 58 and 62 are cut at a 45 angle
relative to the longitudinal axes of the members 52 and 54. The proximal ends
58 and 62 are welded along a seam 64 such that the tube members 52 and 54
extend from each other at a substantially right angle.
The corner member 34 further comprises a rectangular plate member 66
that is welded to one side of the tube members 52 and 54 to define a support
surface 68 at the inside angle formed by the tube members 52 and 54. The
rectangular plate 66 thus braces and strengthens the corner formed by the tube
members 52 and 54 and provides the surface 68 for supporting the machine 21.
In particular, as shown in FIG. 2, the machine 21 comprises first, second,
third,
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and fourth corner portions 70, 72, 74, and 76 that overlap the support
surfaces
68 defined by the rectangular plates 66.
The tube members 52 and 54 each have an inner length L, and an outer
length L2. The significance of these lengths L, and L2 will become apparent
from
the following discussion.
Referring now to the side member 42 of the frame assembly 22, this is
simply a rectangular bar having a length X, and first and second groups 78 and
80 of holes 82 formed therein. The first group of holes 78 is adjacent to a
first
end 84 of the member 42, while a second group 80 is adjacent to a second end
86 thereof.
Referring now for a moment to FIG. 5, depicted therein is the tube
member 52 of the corner member 38, the side member 44, and the screw 50d.
FIG. 5 shows that an outer circumferential path 88 of the side member 44 is
approximately the same (in practice slightly smaller) than an inner perimeter
path
90 of the cross-sectional area of the tube member 52. With the screw 50d
removed, the tube member 52 and side member 44 may move relative to each
other along a common axis A. FIG. 5 also shows that the screw 50d extends
through an attachment hole 92 formed in the tube member 54 and one of the
holes 82 formed in the side member 44.
Comparing'FIGS. 2 and 4, it can be seen that in FIG. 2 the mobile
base 20 is in its largest configuration and in FIG. 4 is in its smallest
configuration.
In particular, the base assembly 20 defines a width dimension W2 and a depth
dimension D2. In FIG. 2, these dimensions are much longer than in FIG. 4.
The largest dimensions of the assembly 20 are defined by the length X, of
the side members 42-48 and the inner length L, of the corner members 52
and 54. In this largest configuration, enough overlap is present between the
side
members 42 and the tube members 52 and 54 such that the weight of the
machine 21 does not cause deflection of the tube members 52 and 54 relative to
the side member 54. In the exemplary embodiment 20, this overlap is a
distance Y, as shown in FIG. 3. In this respect, it should be noted that the
primary weight of the machine 21 is borne through the plate 66 and directly
down
to the wheels 24 and 26 and onto a floor surface 94 in which these wheels 24
and 26 are in contact.
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The smallest configuration (FIG. 4) in which the assembly 20 may be placed
is defined by the lengths of the side members 42-48 and the outer lengths L.
of the
bar members 52 and 54. As shown in FIG. 4, almost all of the area within the
corner members 34-40 is occupied in this configuration.
Referring now to FIGS. 6-8, the locking system 28 of the present invention
will be described in further detail. As mentioned above, the locking system 28
comprises locking assemblies 30 and 32. Each of these assemblies 30 and 32 are
identical, and only the assembly 32 will be described herein in detail.
As shown in FIG. 6-8, the lock assembly 32 comprises a lock member 120,
a lock housing 122, and a drive member 124.
The lock housing 122 defines a lock chamber 126 defined by an inner surface
128 of the housing 122. The chamber 126 comprises a threaded portion 130 and a
cylindrical portion 132.
The lock member 120 has a cylindrical shaft 134 that is snugly received within
the cylindrical portion 132 of the lock cavity 126. The longitudinal axes of
the shaft
134 and cylindrical portion 132 are aligned as shown at B in FIG. 6. The
tolerances
between the shaft 134 and cylindrical portion 132 are such that the lock
member 120
may move relative to the lock housing 122.
A set screw 136 is threaded into the lock housing 122. The set screw 136
selectively allows the user to prevent or allow relative movement between the
lock
member 120 and the lock housing 122.
The drive member 124 has a shaft 138 with a threaded portion 140 and a
cylindrical portion 142. The threaded portion 140 of the drive member shaft
138 is
threadably received by the threaded portion 130 of the lock chamber 126.
Rotation
of the drive shaft 138 about the axis B allows the shaft to be displaced
upward or
downward along the axis B.
A resilient member 144 may be placed on the lock member 122 to prevent
damage to the floor surface 94. A handle 146 may be placed on the drive member
124 to facilitate rotation of he shaft 130 about the axis B.
The purpose and use of the lock system 28 is best understood in the context
of the entire machine base assembly 20. Accordingly, the operation of
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the lock system 28 will be described further below after an explanation of the
use of
the overall machine base assembly 20.
Referring for a moment now to FIG. 3, it can be seen that the front and rear
wheels 24 and 26 are different. The rear wheels are fixed such that they
rotate only
about a horizontal axis, while the front wheels 24 are swivel wheels that can
rotate
about both a horizontal axis and a vertical axis. Both types of wheel
assemblies are
widely available in the marketplace and will not be discussed herein in
detail. This
wheel configuration allows the base 20 to be steered as it rolls.
With the foregoing understanding of the construction of the present invention,
the use of the present invention will now be described in detail.
Initially, the effective footprint of the machine 21 is determined. This is
specifically accomplished by the measuring the width W, and depth Dl of the
particular machine 21 to be supported. Once the width Wl and depth Dl are
known,
the side members 42-48 are inserted into the corner members 34-40 such that
the
width W2 and depth D2 of the assembly 20 is slightly larger than the
corresponding
dimensions of the effective footprint. These dimensions W2 and D2 cannot be
made
too large, however, as enough of the corner portions 68-76 of the machine 21
must
overlap the supports surfaces 68 to provide a stable platform for the machine
21.
The bolts 50 are then inserted through the holes 92 in the bars 52 and 54 and
threaded into the holes 82 in the side members 42. This forms the rigid frame
assembly 22 described above.
At this point, the machine 21 is placed onto the machine base assembly 20
such that the corner portions 68-76 thereof are supported on the support
surfaces 68
of the rectangular plate 66.
At this point, the machine 21 may be rolled on the wheels 24 and 26 to a
desired location. At the desired location, the locking system 28 is used to
prevent
unwanted movement of the machine 21.
In particular, the set screw 136 is backed off so that it does not engage the
lock member 120. The lock member 120 is thus free to fall until it contacts
the floor
surface 94 as shown in FIG. 7. The handle 146 is then grasped and rotated as
shown
by arrow C, in FIG. 8 such that the cylindrical portion 142 of the
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drive member 24 engages an upper end 148 of the lock member 120. Continued
rotation of the handle 146 in the direction Ci will cause the wheel 24 to lift
off the
ground a short distance Z as shown in FIG. 8. At this point, the lock member
120
frictionally engages the floor surface 94 to prevent relative movement between
the
machine 21 and the floor 94. The lock system thus securely locates the machine
21
at its desired location. Additionally, a certain amount of levelling can be
obtained by
altering the distances Z as necessary.
The set screw 136 can be used to further secure the lock member 120 relative
to the lock housing 122 and maintain the distance Z as desired.
If the machine 20 is to be moved, the set screw 136 is disengaged from the
lock member 120. The handle 146 is then turned in the direction opposite the
arrow
C1 until the wheel 24 again touches the ground. The handle 146 will be then
moved
further to a position as shown in FIG. 7 relative to the lock member 120. At
this
point, the lock member 120 can be lifted by hand into the position shown in
FIG. 6,
at which point the set screw 136 is rotated to engage the lock member 120 and
prevent it from dropping back down into contact with the floor surface 94.
The locking system 28 thus provides a secure lock but can easily be engaged
and disengaged as necessary to fix or change the location of the machine 21.
Implicit in the discussion above is the fact that the machine base assembly 20
may be broken down into basically eight separate pieces for shipping and
transportation. In particular, the screws 50 are simply removed and the side
members
42-48 are removed from the corner members 34-40. The broken-down mobile
machine base assembly 20 may thus be stored in a much smaller configuration
whenever desired.
Referring now to FIGS. 9-10, depicted therein is a mobile machine base 220
constructed in accordance with, and embodying, the principles of a second
embodiment of the present invention. The mobile machine base 220 is
constructed
and operates in basically the same manner as the mobile machine base 20
described
above. The mobile machine base 220 will thus be described herein only to the
extent
that it differs from the machine base 20 described above.
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In particular, the machine base 220 comprises a frame assembly 222,
front and rear wheel assemblies 224 and 226, and a locking system 228
comprising first and second locking assemblies 230 and 232. And as shown in
more detail in FIG. 10, the frame assembly 222 comprises first, second, third,
and fourth corner members 234, 236, 238, and 240 and first, second, third, and
fourth side members 242, 244, 246, and 248. The frame assembly 222 further
comprises a plurality of screw members that join the corner members 234-240 to
the side members 242-248.
The frame assembly 222 is similar to the frame assembly 22 described
above, the primary difference being the cross sections of the corner members
234-240 and the side members 242-248.
In particular, as shown in FIG. 11, the corner members and side members
are provided with a generally rectangular cross-sectional area in contrast to
the
generally square rectangular area of the corner members and side members of
the frame assembly 22 described above with reference to FIG. 5. FIG. 11
depicts the corner member 238 and side member 244; the other corner members
and side members have similar cross-sectional areas.
In use, the corner members and side members are joined together and
assembled such that the longer surface of the rectangular cross-sectional area
is
generally vertically arranged.
FIG. 10 further shows that the front wheel assemblies 224 and rear wheel
assemblies 226 are not mounted directly below the corner members as was the
case in the exemplary mobile machine base 20 described above. To the
contrary, as shown in FIG. 9, the wheel assemblies 224 and 226 are mounted on
angle irons 252 and 254 that extend from front sides 256 and 258 of the
frontmost corner members 238 and 240 and from the back sides 260 and 262 of
the backmost corner members 234 and 236. The connections between these
wheel assemblies 224 and 226 and the front and back sides 256-262 are the
same, and only the connection between the rear wheel assembly 226b and
corner member 234 will be described in detail.
Referring initially to FIG. 9, it can be seen that the angle iron 254 has a
generally L-shaped cross section comprising an upper portion 264 and a lower
portion 266. The lower portion 266 is welded to the back side 262 of the
corner
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member 234 such that the lower portion 266 is generally vertically aligned and
the
upper portion 264 is generally horizontally aligned. These portions 264 and
266
extend at right angles from each other.
Referring now to FIG. 10, it can be seen that the angle iron 254b extends a
short distance, approximately two to four inches, from a side surface 268 of
the
corner member 234 towards the adjacent corner member 236. This upper portion
264
is sized and dimensioned to form a suitable mounting surface for the wheel
assembly
226b. Again, the wheel assembly 226 is or may be conventional.
The angle irons perform two basic functions. First, they allow the frame
assembly 222 to be slightly lower during use than the frame assembly 22
described
above. This is because the surfaces on which the wheel assemblies 224 and 226
are
attached are at or near the top of the corner members 234-240 rather than at
the
bottom of these members. In addition, they create a slightly larger footprint
for the
overall machine base 220.
The benefits of the placement of the wheels 224 and 226 is that the level of
the work surface of the machine 21 mounted thereon will not be significantly
higher
than the surface of the machine 21 when the base 220 is not in use. In
addition, the
slightly longer wheel base will slightly increase the stability of the system.
In all other respects, the mobile machine base 220 is constructed, operated,
and used in the same manner as the mobile machine base 20 described above.
Referring now to FIGS. 12 and 13, depicted therein at 320 is a locking
assembly that may be substituted for either or both of the locking assemblies
30 and
32 to form the locking system 28 discussed above.
As shown in FIG. 12 and 13, the lock assembly 320 comprises a lock member
322, a lock housing 324, a drive member 326, and a magnetized portion 328. The
lock housing 324 defines a lock chamber 330 defmed by an inner surface 332 of
the
housing 324. The chamber 330 comprises a threaded portion 334 and a
cylindrical
portion 336.
The lock member 120 has a cylindrical shaft 340 that is snugly received within
the cylindrical portion 336 of the lock chamber 330. The longitudinal axes
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of the shaft 340 and cylindrical chamber portion 336 are aligned along a lock
axis
342. The tolerances between the shaft 340 and cylindrical chamber portion 336
are
such that the lock member 322 may move relative to the lock housing 324.
The drive member 326 has a shaft 350 with a threaded portion 352 and a
cylindrical portion 354. The threaded portion 352 of the drive member shaft
350 is
threadably received by the threaded portion 334 of the lock chamber 330.
Rotation
of the drive shaft 350 about the lock axis 342 allows the shaft to be
displaced upward
or downward along the axis 342.
A resilient member 360 may be placed on the lock member 322 to prevent
damage to the floor surface 94. A handle 362 may be placed or formed on the
drive
member 326 to facilitate rotation of the shaft 350 about the lock axis 342.
The magnetized portion 328 is formed on an upper end 372 of the lock
member 322 opposite the resilient member 360. The exemplary magnetized portion
328 is a small magnet that is glued, threaded, or otherwise fixed in a magnet
cavity
370 of the lock member upper end 372. This arrangement causes the lock member
322 and drive member 326 to be attracted together. Of course, the parts may be
reversed such that the magnetized portion 328 is formed on a lower end 374 of
the
drive member 326, which causes the lock member 322 to be attracted to the
drive
member 326 instead of the other way around.
The purpose of the magnetized portion 328 is to allow the lock member 322
to travel along the lock axis 342 with the drive member 326 while also
allowing axial
rotation of the drive member 326 about the lock axis 342 relative to the lock
member
322.
The locking assembly 320 is similar in use and purpose to the locking
assemblies 30 and 32 described above but differs in one significant detail. In
particular, the locking assembly 320 may be substituted for one or preferably
both of
the locking assemblies 30 and 32; the locking assembly 320 will be attached to
the
base 20 in the same general fashion. The primary difference between the
locking
assembly 320 and the assemblies 30 and 32 is that the locking assembly 320
does not
require a side mounted set screw such as the screw 136 described above.
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Instead, the magnetic portion 328 is attracted to the drive member 326 and
thus causes the lock member 322 to move up with the drive member 326 (e.g.,
from
the configuration of FIG. 7 to the configuration of FIG. 6) when the wheel
assembly
24 supports the weight of the base 20 (and anything thereon) and the drive
member
326 is rotated counterclockwise. The magnetic portion 328 thus obviates the
need for
the user to lift the lock member by hand and tighten a set screw when the base
20 is
to be moved.
However, because only magnetic attraction is used to cause the drive member
326 to lift the lock member 322, the drive member 326 may freely axially
rotate
about the locking axis 342 when the locking system is used to lift the wheel
assemblies 24 off of (e. g. , from the configuration of FIG. 7 to the
configuration of
FIG. 8) or lower the wheel assemblies 24 onto (e. g. , from the configuration
of FIG.
8 to the configuration of FIG. 7) the floor surface 94.
From the foregoing, it should be clear that the invention may be embodied in
other specific forms without departing from the spirit or essential
characteristics
thereof. The present embodiments are therefore to be considered in all
respects as
illustrative and not restrictive.
