Note: Descriptions are shown in the official language in which they were submitted.
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PATENT
FABRIC STACK SHINGLER
Field of the Invention
This invention relates generally to the handling
of flexible planar objects, and more particularly to
the shingling of such objects when presented in stack
form.
Background of the Invention
Industrial manufacturing of a garment currently
requires an inordinate amount of time to handle
material that will eventually comprise a garment. In
excess of 80% of the time spent on any one garment
may go to material handling. Sewing, for example,
represents a surprisingly small proportion of
manufacturing time, relative to handling. One area
of the process that is particularly time-consuming is
separation of a stack of fabric workpieces to allow
easy subsequent handling of individual workpieces.
A workpiece stack can be created by repeatedly
folding a piece Qf fabric onto itself and then
cutting a single pattern clear through all layers of
the multiple-folded cloth. This produces a stack
comprised of flexible planar objects of uniform size,
oriented such that all edges of each object are
juxtaposed with the corresponding edges of each
immediately adjacent object. This arrangement
produces a stack with ends defined by the two
outermost planar objects, and sides defined by the
juxtaposed edges of the several juxtaposed ob~ects,
which sides are all approximately perpendicular to
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PATENT
the two parallel planes containing the end members of
the stack.
By automating the process by which such stacks
are separated, increased efficiency in handling
fabric workpieces can be obtained. However, numerous
difficulties are encountered in attempting to
automate the separation of flexible planar objects.
Unlike the rigid planar objects to which much of the
prior art is addressed, stacks of flexible objects
easily lose a workable shape if their movement is not
strictly controlled. Thus, flexible objects cannot
be expected to "fall into place" of their own accord,
a characteristic upon which art such as U.S. Pat.
Nos. 4,008,890 (PULDA) and 4,049,2S9 (VENTZ) depends.
Much of the prior art also relies on minimal
cohesion between juxtaposed planar surfaces. Where
the planar objects are characterized by more
substantial coefficients of friction, however,
individual sheets are more likely to clump together,
resisting current methods of separation. Although
some of the art has addressed the "clumping"
contingency, it does so only on an "as needed" basis.
It is an object of the present invention to
prepare stacks of flexible planar objects for
subsequent automated separation by shingling the
stack. Once the stack is shingled, an edge of each
individual workpiece is exposed for easier handling.
A further objective is to carry out this function in
a manner which at all times controls the stack such
that neither the stack nor the flexible planar
objects composing said stack lose a workable shape.
Additionally, the present invention is designed to
prevent clumping entirely so that special time-
consuming measures to separate clumps are avoided.
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74667-7
adjacent workpieces. As a result, each workpiece is exposed as
each underlying workpiece is displaced relative to its immediate
neighbor during the shingling process.
To achieve this goal, the stack is first placed on the
platform of the rough shingler assembly. Here, a clamp, or
similar means, is applied to the stack, preferably nearer to one
end, such that the workpieces are immobilized relative to one
another within a region near the clamp. The rough shingler then
bends the stack. To accommodate the fold while conforming to the
shape of surrounding workpieces, each workpiece shifts laterally
reLative to adjacent workpieces at the end of the stack past the
bend and opposite the clamp. However, the clamp prevents any such
shift or displacement within the region of the stack to which it
is applied. To maintain the displacement, the other end of the
stack is clamped. The first clamp is released and the stack is
then unbent. The initial displacement has been carried through
the entire stack.
This process may be repeated indefinitely, so long as
the top workpiece in the stack continues to overlap the bottom
workpiece and both clamps firmly
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Additional objectives, advantages and features of the present
invention are explained as part of the following detailed
description.
SummarY of the Invention
The invention provides an apparatus for spreading a
shingled stack of compressible fabric workpieces, the stack having
an open face such that each underlying workpiece is exposed, the
apparatus comprising: a. a driven roller; b. conveyor means to
drive the stack under the roller wherein the stack is oriented so
that the open face of the stack contacts the roller first; c.
vertically moveable means to apply positive pressure to hold the
roller against the conveyor means thereby causing the roller to
ride upwardly on the open face and the amount of overlap between
successive workpieces in the stack to decrease.
From another aspect, the invention provides a method of
spreading a shingled stack of compressible fabric workpieces
having an amount of overlap between successive workpieces
comprising the steps of: a. moving the stack on a single
conveyor; and b. pressing on the stack as it moves along the
conveyor with a vertically moveable roller driven to rotate
complementary to the conveyor at a circumferential speed less than
a linear conveyor speed, whereby the amount of overlap between
successive workpieces is decreased.
Preferably the stack is subjected to a two-part process.
The first step in the process forms an initial shingle and the
second step further decreases the amount of overlap between
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PATENT
hold both top and bottom workpieces. The longer the
workpieces relative to the distance between the
clamps and the thickness of the stack the more the
stack can be shingled.
Where the rough shingler cannot operate to
provide sufficient shingling, further processing is
necessary. To complete the shingling process, the
rough shingled stack is next treated by a spreader
assembly. The spreader assembly includes at least
one roller subassembly positioned above a conveyor
belt on which the partially shingled stack is riding.
The axle of the roller subassembly lies in a plane
parallel to the conveyor and at an angle
perpendicular to the direction of the conveyor belt.
The stack is positioned upon the conveyor so that its
open side faces the roller subassemblies and the
direction of the conveyor. In the open side of a
shingled stack each underlapping workpiece is
exposed. In the closed side, each underlapping
workpiece is hidden.
A preshingled stack is driven under a roller
subassembly or series of subassemblies. As the
conveyor carries the stack beneath a roller
subassembly, the subassembly is lowered so that the
rollers of the subassembly are brought into contact
with the open side of the stack. The rollers operate
to recline and further shingle the stack. They do so
by a combination of roller rotation in the same
direction as the direction of the stack in
combination with the application of pressure onto the
shingled stack.
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PATENT
Brief Description of the Drawinqs
The preferred embodiment of the invention is
described in detail below in conjunction with the
illustrations in which:
Figure 1 is a perspective view of the rough
shingler assembly in combination with the spreader
assembly;
Figure 2A through 2F show the steps necessary to
rough shingle a stack of fabric workpieces; and
Figure 3 shows a side view of the spreader
assembly with the second roller subassembly engaged.
Detailed Description of a Preferred Embodiment
Figure 1 illustrates one arrangement of the
preferred embodiment. This arrangement demonstrates
a close spacial proximity that is appropriate for
rough shingler assembly 100 and spreader assembly
200, in view of the close temporal proximity in which
the two assemblies operate during the particular
shingling process disclosed herein, as well as in the
overall manufacturing process.
In this arrangement, a fabric workpiece stack is
placed upon rough shingler platform 110. The rough
shingler platform 110 comprises two adjoining
subplates, primary subplate 112 and secondary
subplate 114. The axis 116 of the platform 110 joins
the two subplates 112 and 114. A primary clamp 118
is positioned to clamp a stack 122 of objects against
the primary subplate 112 and a secondary clamp 120 is
positioned to clamp the same stack 122 against the
secondary subplate 114. The sides of the stack which
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will be offset in a shingled fashion are preferably
parallel to the axis 116.
Figures 2A through 2F show the sequence of steps
taken by the rough shingler 100. Figure 2A shows
that a workpiece stack has been delivered to the
platform 110. This may be done through any standard
means such as by a conveyor. The stack 120 straddles
the axis 116 and is positioned under both primary
clamp 118 and secondary clamp 120. In Figure 2B, the
primary clamp 118 is activated to firmly grasp the
stack 122. The activation of the clamps may be
controlled by mechanical, pneumatic, hydraulic or
other means and is preferably automatically
controlled. This action holds the workpieces in the
stack immobile relative to one another in the region
near to the primary clamp 118.
In Figure 2C the secondary subplate 114 is
rotated about the axis 116 bending the workpieces.
The subplate 114 may be controlled by mechanical,
pneumatic, hydraulic or other means. These control
means are preferably automatically actuated in
sequence with the clamps. Any suitable control means
may be used. Each workpiece is bent around the axis
116. However, each workpiece that is successively
farther from the platform 110 is bent through an arc
having a larger radius of curvature. Accordingly,
because each workpiece is the same length the ends of
the stack positioned over the secondary subplate 114
are displaced from one another. The larger the angle
that the secondary subplate rotates through, the
larger the displacement of the ends of the stack 122.
The ends will be displaced whether the secondary
subplate 114 is rotated upward or downward (as
shown). It should be noted that if the subplate 114
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PATENT
is rotated upward the open end of the stack will be
at the opposite end of the stack. Depending upon the
characteristics of the workpiece attempting to rotate
the subplate 114 up may tend to buckle the fabric and
fail to shingle the stack 122.
Figure 2D shows that the secondary clamp 120 is
activated to firmly grasp the stack 122. This action
holds the workpieces in the stack immobile relative
to one another in the region near to the secondary
clamp 120. Next, Figure 2E shows that the primary
clamp 118 is deactivated. The workpieces are no
longer immobile relative to one another over the
primary subplate 112. Lastly, in Figure 2F,
secondary subplate 114 is returned to its starting
position parallel to primary subplate 112. Because
the workpieces are no longer bent through various
radii of curvature the amount displacement between
the ends of the stack 122 held by the secondary clamp
120 is transferred throughout the stack 122.
Additional displacement of the workpieces may be
obtained by repeating that part of the process
described above, so long as previous displacement has
not removed any workpieces from the areas subject to
detachable affixation by clamps 118 and 120 and so
long as the top workpiece still overlies at least in
part the bottom workpiece.
Where the workpieces are short in length, such
as for blue jean patch pockets, the rough shingling
operation may not be able to achieve sufficient
shingling for suitable handling in subsequent
operations. In such circumstances, the spreader
assembly 200 is used to spread the shingled stack out
even more. In the preferred embodiment of Figure 1,
the rough shingled stack is transported from the
rough shingler loo to the spreader assembly 200. The
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stack may be transported by any known method such as
a conveyor.
The spreader assembly 200 shown in Figure 3
comprises a conveyor 210 which transports the stack
122 therethrough. Additionally, roller assemblies
220 are utilized to spread out the fabric. The
roller assemblies include a roller 222 driven by a
belt 224 in the direction of the conveyor 210 and
supported by a moveable arm 226. Positive pressure
is exerted against the conveyor 210 by the roller 222
through an air cylinder 228. Springs, weight or
other means may be used.
The open edge of the stack 122 is driven under
the roller 222 by the conveyor 210. The stack 122
forces the roller 222 to rise up and ride along the
stack 122. Because the workpieces are compressible,
a small wave is developed due to the pressure of the
roller 222 on the stack 122. This wave is pushed
through the stack thereby increasing the amount of
shingling (spreading out the stack 122). The size of
the rollers 222 are preferably selected to have an
appropriate angle of attack to the stack 122 based
upon the amount of shingle expected. Thus, rollers
of different sizes can be used throughout a single
shingle spreader assembly as shown in Figure 3.
While a particularly preferred embodiment of
this invention has been described above in detail, it
is understood that this embodiment is illustrative
only of the principles of this invention. Numerous
equivalents, modifications and variations of the
described structure will become readily apparent to
those skilled in the art. Thus, the scope of this
invention is limited solely by the claims appended
hereto.
