Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Field Of The Invention
. ._
The pre~ent invention relates to an automated
placket shirt front forming machine and rnethod for se~ing
placket shirts applicable to chain stitch, lock stitch and
other types of sewing machines to provide a completely
automatic apparatus and method which allows the machine
operator to sew placket shirt fronts without having to master
the art of sewing. More particularly, the present invention
pertains to apparatus and method which requires the operator ~.
only to properly line up the placket shirt front, the placket
~nd liner before activating the machine which then
automatically completes all sewing, mitre and thread cutting
and stacking of the finished placket shirt frontO
The apparatus includes means for clamping and
transferring the properly aligned parts to a means for sewing
and slitting the placket shirt front, means for mitre
cutting, thread cutting and stackin~ finished placket shirt
fronts. The method of the invention includes the automati~
sewing, mitring and stacking of placket shirt front.s by
initiating the sewing of the placket shirt front, placket and
liner intermediat~ the ends of the placket shirt front and
sewin~ to one end of the placket shirt front.
The present method and apparatus of the invention
provides for the automatic positioning of the material under
the sewing machine and automatically sewing and incremen~ally
advancing the placket shirt front maintained by ~he sew clamp
through the sewing machine in coordination with the movement
of the needle and sli~ting operation from a point
intermediate the ends of the placket shirt front to one end o~
the placket shirt front. The invention provides an
inexpensively formed placket shirt front that reducPs lahor
and waste of placket shirt material components while
increasing the precision and quality of the finished ~arment.
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Description Of The Prior Art
. _ ,
The prior art includes a variety of patents
pertaining to sc~mi-autornatic sewing machines for sewing or
providing assistance in the formation of c3arments such as
placket shirt fronts. It is well recognized in the prior art
and the placket shirt industry that the formation of placket
shirt fronts involves considerable time, labor and skill of
the placket sewing machine operator in not only positioning
the placket shirt front, placket and liner but also in
maintaining the position of the components during sewing so
that the seams are straight and the placket shirt front when
turned is not crooked, puckered or otherwise of an unaccept-
able quality. It is also recognized by those skilled in the
art that formation of placket shirt fronts having buttoned
fronts are generally even more difficult to produce as the
tolerances in properly laying out and sewing the components of
placket shirt are more demanding. For example, if stltching on
either side of the placket or the slitting is not exact, the
placket shirts formed may have a non-aligned front producing
a "seconds" quality shirt. The skill of the sewing machine
operator has heretofore been extremely important in lining up
and sewing up the placket from the top or neck portion of the
shirt down to the center or chest protion of the shirt. The
traditional method of sewing placket shirts and improvement~
in the prior art method of sewing placket type shirt~ from
the neck down has been the subject of various patents.
One such patent, Scott U.S. Patent 3,871~307
pertains to a placket forming machine which employs a chain
stitch sewing machine and provides a fabric workpiece clamp
which is employed to clamp the garment and ther~after
advance along a track at a xegulated speed employing a
hydraulic cylinder to advance the garment and clamp in the
sewing operation. After completion of the sewing machine, a
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pair of knlves are automatically engaged to pick up the
stit~h forming threads and to sever the threads. After the
threads are severed, the clamp returns to the start pOsition.
The operation of the chain stitch machine in Scott
et al~ U.S. Patent 3,871,307 at best provides a semi~
automated placket forming machine that requires considerable
attention of the sewing machine operator and does not
position, mitret remove, or sew placket shir~ fronts
utilizing either the apparatus or method of the present
invention to ~orm the placket shirt front and also stack the
finished product. In U.S. Patent 3,871,307 the clamp assists
the placket machine operator by guidinq the aligned placket
shirt parts through the machine. The apparatus and method
disclosed in U.S. Patent 3,871,307 is materially different
than provided by the present invention since in the prior art
patent the operator s~ill begins sewing o~ the placket shirt and
thereafter sews downt~ard from the neck to the center of the
shirt. Thereafter a chain stitch cutting apparatus engages
the thread and cuts the thread so that the placket shirt
~o front may thereafter be removed by the operator.
- The operation of the placket shirt forminy machine
as described in U.S. Patent 3,871,307 requires the operator
to still operate the machine in coordination with the
guidance of the placket clamp and necessltates the mitre
cutting and stacking of the placket shirt front before
beginning work on the formation of a second placket shirt
which similarly requires the operator to llne up ~he shirt
front, placket and liner.
The present invention by way of contra~t is not
limited to any particular type of sewing machine and is
completely automatic in that it only requires the operator to
layer the garment materials. Once the materials are properly
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layered, the apparatus of the present invention automatically
positions the garment under a sew clamp which then positions
the garment under the sewing machine, sews, mitre cuts, cuts
sewing threads and stacks the shirt front without further
S attention or skill of the operator. The fully automatic
process of the invention is aided by a novel meth~d in which
the traditional method of sewing placket shirts starting from
the neck of the shirt and sewing down to the center of the
placket shir~ is replaced by a method in which the placket
shirt is sewn starting from the center portion of the shirt
up to the neck or top of the shirt while the machine is
slitting the liner, placket and shirt front. The method of
the present invention allows the construction of a fully
automated placket shirt forming machine that is not subject
to the disad~antages and limitations in prior art placket
sewing machines.
In Dorosz, U.S. Patent 3,814,038 a sewing machine
is provided having a pallet for supporting a workpiece for
movement relative to the tool. The pallet is mounted on a
moving means that is synchronized for movement with respect
to the operation of the sewing machine needles. U.S. Patent
3,814,038 does not pertain to pla~ket forming machines.
Dorosz does not suggest or contemplate the utili2ation o the
present combination of elements and new and useful result
provided by the transfer clamp, sew clamp and the mitring,
cutting, and stacking operation of the finished product that
is achieved by the present invention. Furthermore, the
provision for the timed motion of the pallet utilizes
apparatus that is entirely different from ~he present
invention as the timed motion for the movement of the rack
and pinion in relation to the penetration of the needle
utilizes a nipple and eccentric cam arrangement.
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The present inventi~n unlike the prior art begins
the sewing of the placket shi.t front, placket and liner by
initiating the slitting and sewing of the placket shirt fr~nt
at a point at the lowest point of the placket shirt and
thereafter sewing up to the top or neck position of the
placket shirt thereby eliminating much o f the labor, attention
and skill hereto~ore required of sewing machine operators to
not only increase productivity but also the accuracy and -~
quality of the placket shirt fronts sewn in accordance with
the method and apparatus of the present invention.
As a result of the method and apparatus the present
invention provides an enormous economic advantage in the
production of high quality placket shirt fronts without -
having to rely upon the skill of the placket sewing machine
lS operator. One of the distinguishing features of the present
invention is the utilization of a transfer clamp and sew
clamp to increase productivity and to initiate the sewing
operation of the placket shirt from the center or mid portion
of the placket to the top or the neck portion of the shirt to
provide a method and apparatus for increasing not only
productivity and accuracy of the placket sewn shirt but also
assist in the cuttin~, mitring and removal of the placket
shirt front and the subsequent stackinc3 of the finished
placket shirt fronts.
SUMMARY OF' THE INVENTION
The disadvantages and limitations of prior art
apparatus and methods for automating sewing machines and
placket shirt front forming machines is obviated by the
present invention which provides a fully automated, placket
shirt front sewing machine and method of sewing placket shirt
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fronts that eliminates the labor and skill heretofore
required in the formation of the placket shirt front and
increases accuracy and productivity. The rnethod and
apparatus of the invention employs a high speed-type
S operation capable of producing about six shirts a minute or
over 360 placket shirt fronts per hour if the operator could
layer the components at least as fast as the present machine
can sew, mitre and stack the finished product. In
experimental operations of machines constructed in accordance
with the invention well over 1,800 placket shirt fronts per
day were produced and required only the attention of the
automated placket sewing machine operator in layering and .~:
lining up the placket shirt front, placket and liner and
thereafter starting the machine.
Apparatus constructed in accordance with the
broadest aspects of the invention automatically engages
garments and guides them to a sewing machine which initiates
the sewing of the garment at a point intermediate the ends of
the garment and sews from that point to one of the ends of
the garmentO In the preferred embodiment of the invention a
transfer clamp is utilized to guide a properly layered
garment to a sew clamp which automatically clamps the layered
placket shirt front components and pos.itions the component~
under the sewing machine thereaEter activating the sewing
machine to F,lit and sew the components together.
Upon completion of the sewing and slitting of the
placket shirt components the machine automatically mitres,
cuts the thread and stacks the finished placket shirt front
while the operator of the apparatus is free to properly layer
and line up a second placket shirt front, placket and liner
so that upon completion of the stacking operation the sew
clamp returns to automatically engage the placket shirt
components and transfer them to the sew clamp of the placket
L ~ ~ 7 ~ ~ Z 7
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machine for subsequent sewing and stacking.
The ad~antages incumbent in the present apparatus
for forming placket shirt fron~s stem in part from the method
of sewing placket shirts which initiates the s~wing op~ration
S at a point corresponding to the fullest leng~h of the placket
shirt opening and sews from that point, which is generally
about the chest portion of the shirt, up to the top or neck
pertion of the placket shirt. Placke~ shir~ fronts sewn in
accordance with the invention not only assist in reducing
"seeonds" quality shirts hut also increases the accuracy of
shirts produced while providing means for readily and
mechanically removing the placket shirt front from the
placket sewing machine without requiring the attention and
time of the placket shirt sewing machine operator to remove
the garment from the machinc.
The placket machine operator is consequently free
to again line up the components while the machine is sewingt
mitring and stackiny the previous ~arment. In the preferred
embodiment two guides are employed to assist the operator in
properly lining up the placket shirt componen~s of placket
shirt front, placket and placket liner~ The first guide
device m~y conveniently consist of a marked positioninq area
or index on the placket machine work table to assist in the
positioning and cenkering o~ the placket shirt front with the
placket and liner.
A second guide for assisting in the positioning ~
the layers of the garment may be provided in the form of a
light having a cross hair shining on the work table surface
or other positioning means to assure the proper lining up of
the components of the placket shirt front. In this
embodiment all that is required is the lining up of the neck
of the placket shirt ~ody with the first guide means and
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thereafter lining the placket with the neck of the placket
shirt body and the second guide means. Thereafter the liner
is aligned with the neck of the placket shirt body and the
second guide means to assure that the placket shirt front,
placket and liner will be slit, sewn and properly mitred by
the automa~ed placket sewing machine of the present
invention.
The activation of the present apparatus requires
only that the operator depress the placket sewing machine
start button to thereafter result in the placket machine
automatically sewing the placket shirt without further
attention of the placket machine operator. It will be
recognized the advantages of this system allows the
operator's attention to be directed to aligning an additional
placket shirt front, placket an~ liner without having
to divert attention to the operation of the sewing machine,
stacker or any other aspect of the sewing of the placket
shirt front and thereby increases production by at least 600
shirts per day over current production methoc1s since the
completion of the cycle takes about sixteen hundreths of a
minute from the time they are slit, sewn, mitrecl and stack~d
at the back ~nd of the machine.
The activation of the start button activates a
transfer clamp which moves from a rest position to a position
above the layered placket shlrt components at which time a
second switch is activated causing the transfer clamp to
clamp the layered garment composed of the placket shirt
liner, placket and placket shirt front. The transfer clamp
upon clamping the components activates a further switch which
transports the cl~mped layers of cloth from the work area
portion of the machine to the sew clamp by the activation of
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a transfer clamp cylinder which positions the layers of cloth
underneath the sew clamp. As soon as the transfer clamp has
poqitioned the layered garment under the sew clamp a further
switch is activated resulting in the disengagement of the
transfer clamp and its movement to a rest position which is
a position intermediate the ~ew clamp and woxk area where the
operator may be stacking a further shirt front, placket and
liner~
The movement of the ~ransfer clamp to the rest
position activates a switch causing the sew clamp to drop
down and positively clamp the placket shirt ~ront, placket
and liner which in turn initiates the travel of the sew clamp
toward the foot of the sewing machine which as a result of
the configuration of the sew clamp allows slitting of the
garment prior to the initiation of the sewing operation.
Preferably, one ox more air jets are employed to blow the
layered ma~erial past the foot of the sewing machine to
assist in the positioning of the garment under the foot of
the sewing machine prior to the lowering of the modified
sewing machine foot and activation of the sewing machine. It
will be recognized that the ~unction of the transfer clamp
and sew clamp may be combined so that the transfer clamp and
sew clamp may be effectively combined into a single means ~or
transferring a placket shirt ~ront, placket and liner to the
sewing machine.
Once the placket shirt front, placket and liner are
positioned under the sewing machine and the foot of the
sewing machine is lowered on the sew clamp o~er the layered
garment at a point corresponding to the center of the placket
shirt front or the lowest paxt of th~ shirt from the neck at
which the placket shirt front is designed to extend, the
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slitting and se~ing is initiated. Once sewing is initiated,
the movement of the sew clamp is thereafter advanced the
length of a single stitch and only when the sewing needles
are not engaged in the garment.
~he advancement of the qarment may be provided by
for example a rack and pinion which may be driven by the hand
wheel of the sewing mahine by the connection of an eccentric
arm to provide a one way ratcheting through an indexing
clutch that preferably advances the rack fvr movement of the
sew clamp in a timed relationship to the operation of thé
needles of the sewing machine. It will be recognized that at
whatever the speed at which the sewing machine is operated
will similarly control the speed of the sew clamp which is
geared through the one way indexing clutch to ratchet the sew
clamp through the sewing machine until the sewing machine has
completed sewing the placket from a point intermediate the
ends of the garment to one end of the garment.
In operation of the air clutch the rack and pinion
mechanism is indexed to reach a predetermined position which
corresponds to the neck portion of the shirt at which point
the sewing machine stops. At thi.s point a switch is
activated which pos.itions the sewing needles out of the
cloth, actuates~ cylinder to lift the foot, and releases th~
}~ thread tension and thereafter advances the sewclamp and 3ewn
and slit garment to the proper po~ition for the mitre cut.
The mitre cutting cylinder is activated to automatically
provide the mitre cut which may occur before or after but
preferably after the shirt tail is clamped in the stacker
unit.
After the mitre is cut the pressure on the sewing
machine foot is released after the shirt is clamped the sew
clamp is returned to the rest position to thereafter activat2 a
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cylinder connected to the raker bar which pu115 the shirt
and sewn layered parts from the sewing machine which places
`~ the threads in at~t state for cutting. During the
extension 3f the raker bar the threads are severed by a novel
impact cutter. At the end of travel of the raker bar in the
stacker unit the clamp is disengaged and the transfer clamp
is free to move from its rest position to clamp a second shirt
set up on the ~ork table on the placket sewing machine if
the start button of the machine has again been activated
by the operator signifying the completion of the task o~
layering the placket shirt front, placket and liner prior to
the cycling of the machine.
It will be recogni~ed that the present method ~nd
apparatus constructed in accordance therewith may be adapted
to not only utilize a lock stitch machine as heretofore
described, but also chain stitch machines and othcr forms of
sewing machines. The method of sewing the placket shirt from
a position at or near the center of the shirt to the top or
the neck of the placket shirt allows the placket shirt to be
more quickly and accurately sewn and removed frorn the shirt
front machine. In contrast to the prior art it will be
further recognized that the present placket sewin~ machine is
completely automated with the attention of the operator being
required only to stack the placket shirt front, placket and
liner and engage the machine. Thereafter, the automatic
placket sewing machine transfers, sews, cuts and stacks the
final product at the back end of the machine.
Among the many advantages incumbent in ~he present
invention is that the automated placket sewing machine of the
present invention eliminates much of the time, skilled labor
and error of prior art operations. Furthermore, the sewing
of the placket from the center of the shirt to the top of the
shirt eliminates many of the problems involved in the removal
of the placket shirt front from the sewing machine and allows
a wide variety of mechanisms to be utilized to perform the
positioning, slitting, sewing, mitring and stacking of a
finished placket shirt or ~ther garment. Moreover, as a
consequence of the design and construction of the invention,
the present invention is far less expensive to operate and
provides a more precisely formed placket shirt front at a
higher rate of production than has heretofore been
accomplished by prior art apparatus.
DESCRIPTION OF THE DRAWINGS
Other advantages of the invention will become
apparent to those skilled in the art from the following
detailed description of the invention in conjunction with the
appended drawings in which:
FIGURE 1 is a perspective view of a placket shirt
fxont forming machine constructed in accordance with the
invention;
FIGURE 2 is a front elevati.orl view of a portion of
a placket machine utilizing the presen~ inv~ntj.on;
FIGURE 3 is ~ top plan view illus~ratinc3 a portion
of the work table of the automated pl~cket formin-J machine of
the invention;
FIGURE 4 is a top plan view of a liner lllustrating
a guide means provided in accordance with the invention,
FIGURE 5 is a top plan view illustrating the
transfer clamp and placket aligning guide means;
FIGURE 6 is a perspective view of a portion of a
placket forming machine of the present invention;
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FIGURE 7 is a side elevation view from the right
side of a fully automated placket sewing machine in
accordance with the invention;
FIGURE ~ is a rear elevational view of the means
for driving the placket forming machine of the present
invention;
FIGURE 9 is a portion of a left side elevation view
of a portion of the placket forming machine in accordance
with the present invention;
FIGURE 10 is a perspective view of the mitre
positioning engagement mechanism; ~
FIGURE 11 is a partial side elevational view of ~'
the mitre, thread cutter and a portion of the sewing machine
of the automated placket forming machine;
FIGURE 12 is an elevational view from the rear of
one form of the placket forming machine of the invention;
FIGURE 13 is a right side elevational view of
the stacker portion of the placket forming machine; and
FIG~RE 14 is a left side elevationa3. view of the
stacker of FIGURE 13.
DETALED DESCRIPTION OF THE INVENTION
Referring now to FIGURES 1 and 2 a placket sh~rt
forming machine 20 constructed in accordance with the
invention is provided having a flat smooth table 22.
Table 22 may be conveniently divided into areas 24, 26, and
280 Area 24 may be utilized for receiving placket shir~
bodies 30 which can be layered in work area 26 along with
placket 32 and liner 34 in a manner well known in the art.
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To facilitate production a work box 36 may be attached to a
work t~ble 22 utilizing a support structure 38, although it
will be recognized that alternative configurations and
utilizatio~ of the work area Z6 and work box 36 are possible
to suit particular ~equirements. Work area 26 may
con~eniently include a first alignment means such as
marker 40 for centering an~ positioning the top or neck areas
of body 30, placket 32 and liner 34 on work area 26.
Work box 36 provides a support for the attachment
of a second alignment means such as positioning and alignment
of placket shirt body 30, placket 32 and liner 34 on the work
table 22. First guide means or marker 40 may be adjustable -'
or include markings to accomodate the positionin~ of a
variety of styles of placket shirt fronts. Second guide
means 42 is preferably adjustable along with the travel of
the sew clamp to accomodate variations in desired length of
placket shirt front openings. Work table 22 is preferably
smooth and provides little friction to the sliding of cloth
across the surface from areas 26 to 28 for reasons that will
become apparent. ,
With reference now to FIGVRES 1, 2~ 3, 4 and 5 it
will be appreciated that the operator of the fully au~omated
placket machine has only to properly layer placlcet shirt
body 30, placket 32 and liner 34 in work area 26. To assist
2~ the operator in t'ne proper alignment of the shirt body 30,
placket 32, and liner 34 a first ~uide means 40 is provided
in work area 26 of table 22. The operator thereafter aligns
the placket 32 and liner 34 by utilizing the shirt body 30
and guide means 40 in con~unction with a second guide means
42 to assure the proper positioning of the garment on table
~2 so that the automatic placket sewing machine of the
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in~ention may thereafter sew, mitre, cut and stack the sewn
placket shirt front without reyUiring further labor or
attention of the operator of the placket machine.
In the alignment and layerin~ of the garment the
operator lines up the center of the neck portion 46 in
alignment with the first guide means 40 and then takes a
placket 32 and similarly aligns it with guide means 40 and
the light provided by second guide means 42 so that the cross
hair 48 ~FIG. 4) is directed down to a T-shaped cut in the
placket to assist in the alignment of the placket shirt liarts
in the manufacture of placket shirts. The operator then
takes a liner 34 and similarly aligns it at the neck
portion 46 on the placket 32 in alignment with the first
guide means 40 and the second guide means 42 so that cross
hair 48 is similarly in alignment with the notched out
portion 52 of the bottom portion 50 of the liner 34 (FIG. 4).
Once the alignment and layering of the garment
components is complete, the operator of the automatic placket
sewing machine ha~ only to depress start switch 54 to
complete not only the placket sewing, but also the cutting,
mitring and stacking of the finished placket shirt front. As
is understood by those skilled in the art of placket shirt
construction the proper positioning and maintenance of layers
during the sewing operation is the most critical part in the
process of making placket shirt~. This aspect of the
construction of plac]cet shirt fronts is achieved with a great
deal of precision in the present invention by the utilization
of clamps to allgn and maintain the position of ~he layers of
cloth in the fully automated operation of slitting, sewing,
mitring and stacking of the garment. While the present
automatic placket machine in the preferred cmbodiment
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utilizes air driven cylinders to actuate the various
mechanical movements it will be understood by those skilled
in the axt that the present inven-tion may be utilized by
employing other fluid, electrical or other driving means.
Once switch 54 is depressed the operation ~f the
automated placket forming machine is provided by the
triygering of additional switches by ~he mechanical motion
and timed inter-relationship of the functions of transferriny
the cloth to ~he sewing machine, slitting, sewing, mitring,
cutting the threads and the ultimate stacking of the finished
placket shirt front. In this manner, errors resulting from
inadvertence, inattention or fatigue can be eliminated by the
provision of the present completely automated placket shirt
forming machine. Actuation of swi~ch $4 results in transfer
clamp assembly 56 moving from its rest position as
illustrated in FIG. 1 to work area 26 on table 22 to a
position above the layers of cloth formin~ the placket shirt
front. Transfer clamp assembly 56 is positioned over the
layered shirt front by the actuation of a transfer clamp
cylinder 58 extending rod 60 which may be conveniently
actuated by air pressure, hydraulic pressure or other fluid
or electrical impulses. Lower ~rame 62 of transcx ciamp
assembly may be of a rectangular configuration which Ihay
travel on rails 6~ and 66 designed t~ span work areas~26
and 28 of table 22. Upon completion of travel to a po~ition
above the placket shirt body lower frame 62 of transfex clamp
assembly 56 contacts a switch 68 which causes the top,portion
70 of transfer clamp assembly 56 to clamp down on placket
shirt front 30, placket 32 and liner 34 which in clamping
down ~FIGURE 5) results in the activation of switch 72.
Once switch 72 is activated rod 60 is retracted in
cylinder 58 thereby transferxing clamp assembly 56 and
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placket shirt body 30, placket 32 and liner 34 acxoss the
surface of table 22 to area 28 and position the transfer clamp
assembly under sew clamp or sew clamp assembly 74. At the
end of the travel o~ rod 60 switch 76 is closed which
S releases air p~essure in both cylinder S8 and cylinder 78
which as a result of the action of spring 80 raises transfer
clamp portion 70 to release the placket shirt body, placket
and liner in the alignment position for subsequent clamping
and sewing under sew clamp assembly 74. The release of pres-
sure in cylinder 78 and ~he action of spring 80 lifts the topportion 70 of transfer clamp assembly 56 to clear the raised
sew clamp assembly 74 and raised sewing machine foot
assembly 82 and at the same time activates a further
switch 86. The activation of switch 86 energizes cylinder 57
to result in the travel of transfer clamp assembly 56 back to
its rest position as illustrated in FIG. 1.
A particularly advantageous aspec~ of the present
invention is that transfer clamp assembly 56 places the
placket shirt body, placket and liner directly under the sew
clamp assembly 74 so that the center portion 84 (FIG. 4) of
liner 34 which is layered over placket and shirt body and which
may be partially pre-slit, is positioned dirPctly under ~ew clam
assembly 74 so that the center slot 90 (FXG. 6) of sew
clamp 74 is in direct alignment with the partially per~orated
center portion 84 o the liner ~4 (FIG. 4). It will be
,. recognized that center portion 84 of the liner which is
layered over the placket and shirt body is in slot 90 of sew
clamp 74 and is in direct alignment with slitter knife 94
al50 disposed on the sewing needle assembly 96 of sewing
machine 98. As heretofore described the se~ing machine
employed is for the purposes of illustration a lock stitch
machine made by one of the commercial manufacturers such as
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Singer but i~ will also be understood that t~le prescnt
invention is applicable to a variety of machines such as
chain stitch and other types of sewing machines.
Needles 100 and 102 are in direct alignment with
510ts 104 and 108 of sew clamp assembly 74 so that upon
actua~ion of sewing machine 98 the liner, placket and shirt
body are automatically both slit and sewn during the
operation of sewing machine 98. ~he method.of the present
invention along with the efficient s~w clamp assembly 74
10 allows the cloth to be slit and sewn at abou~ the same time
during the operation of the sewing machine. As heretofore
been described the activation of switch 86 results in the . .
activation of cylinder S7 resulting in the return of transfer
clamp assembly 56 to its rest position as illustrated in
Figure 1. Once transfer clamp assembly 56 has moved to the
rest position, switch 110 is activated (FIG. 2) which
activat~s cylinder 112 and causes the sew clamp assembly 74
to firmly clamp the placket shirt body, placket and liner.
The clamp of sew clamp assembly 74 on the placket shirt body,
placket and liner results in lowering of the sew clamp on
guide rods 114 and 116 resulting in the activaticn of a
switch 120 (FIG. 6~.
Activation of swi.tch 120 results .in the activation
of air jets 122 and 124 which are directed toward sewiny
machine 98 and assist in blowing the tail of the shirt out
and under the sewing machine foot assembly 82. In this
manner, the tail portion of shirt body 30 is guided toward
the stacker Ullit 126 for subsequent slitting, sewing,
mitring, thread cutting and stacking. Switch 120 also may
3~ activate sew clamp cylinder 128 to advance the sew clamp to
the start sew position under sewing machine foot assembly 82.
The advancement of the sew clamp assembly 74 by cylinder 128
`~ to the start sew position, lines up the needles 100 and 102
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and the slitter knife 94 with slots 104, 108 and 90 of ~he
sew clamp assembly 74. Upon the advancement of sew clamp 74
to its start sew position under foot assembly 82 of sewing
machine 98 a switch 130 is activated causing cylinder 132 to
drop foot assembly 82 on top of sew clamp 74. Foot assembly
may conveniently include four rollers 134 for rolling on the
top of sew clamp assembly 74 whirh urther assists in the
operation of the slitter knife 94 so that slitting of ~he
garment can occur either before or simultaneously with t~
sewing operation. It will be recognized that sewing of the
placket shirt begins at the center or a point inter~ediate - '~
the ends of the garment such as at position 136 and sews from
there to the top of the neck portion of the shirt to provide
the advantages of the present invention.
lS The activation of switch 130 may also be utilized
to activate air clutch 138 which may be a suitable air clutch
model such as Horton model BW air clutch. Sew clamp
assembly 74 which is supported by arm 118 is pushed to sew
position by cylinder 128 and is associated with air
clutch 138 through a pinion 140 which is associated with
rack 142. Rack 142 is operatively connected to sew clamp 74
by supports 144 and 146 at one end and axm 118 at the other
end which are adapted for slideable engagement on rods 1~8
and 150 and which when engaged at the start sew position is
thereafter controlled by the action of air clutch 138 and the
drive of rack 142 by pinion 140.
Activation of switch 130 can also result in
starting the operation of sewing machine 98 which is
connect~d to air clutch 138 by means of a cam assembly 152
which results in an incremental ratcheting of pinion 140 in
~ack 142 resulting in sew clamp assembly 74 being
~L'7~
--19~
.
incrementally advanced in coordination with the length of the
stitches sewn by needles 100 and 102 and the speed oP the
sewing machine in the advancement of the sew clamp 74.
Referring now to ~igs. 6, 7, 8, 9 and 10 the
S operation of sewing machine 98 in coordination with the
advancement of sew clamp 74 will be briefly examined. Cam
assembly 152 provides for the incremental advancement of sew
clamp 74 by employing an arm 154 which is connected to air
clutch 138 by a shaft 156 having a slotted arm member 158
having a slot 160 for adjustment of the cam assembly 152
which is attached to the sewing machine handwheel 162. Cam ..
- assembly 152 is eccentrically mounted to center shaft lS4 of
sewing machine handwheel 162 by a bearing assembly 166 of
arm 154 so that once in every revolution rack 142 advances
when needles 100 and 102 are withdrawn from the garment.
The function of slot 160 is to adjustably position
a pin 168 in the slot so that upon each revolution of.'che
sewing machine handwheel the rack 142 is advanced in
accordance with the length of each stitch sewn by nee~les 100
and 102 of the sewing machine 98. The air clu~ch 138 and a
one directional clutch housed in the shaft area of.arm 158
is utilized for incrementally advancing pin.ion 140 in
rack 142. After dropping of sewing machine foot assembly 82
by cylincler 132 switch 130 or pre~erably a further switch 169
which causes the machine to begin sewing and advancing as
pinion lqO incrementally advances along rack 142. Thë
sewing, slitting and movement of the sew clamp 74 past the
sewing machine 98 continues until the sewing machine and sew
clamp 74 has advanced a predetermined distance which ,
corresponds to the length of the placket shirt opening from
the center of the shirt to the top or neck portion o~ the
shirt.
~'7~
The method of the present invention unlike prior
art methods and apparatus for sewing plack~t shirts, starts
at the center of the shirt and sews up to the top or neck
portion of the shirt. The present method consequently is
conveniently adaptable to chain stitch, lock stitch and other
types of sewing machines to provide an easy method for
removing the sewn, slit and mitred placket shirt front from
sewing machine 98.
. Indexing of the rack 142 and operation of th~
sewing machine continues until the machine has reached the
end of travel. The length of travel of the rack 142 may be
conveniently set by the positioning of a stop guage 170 in a
slotted member 172 so that as soon as rack 142 has traveled
the predetermined distance a switch 176 i5 contacted which
corresponds to the predetermined point 180 on sew clamp
assembly 74. This position may be conveniently altered by
modifyin~ the position of the stop guage 110 in slot 184 of
slo~ted member 172. As soon as switch 176 is contacted
sewing machine motor 190, located underneath the sewing
machine 98 is stopped and air clutch 138 is deactivated so
that pinion l~O is free to rotate and travel in rack 142.
Referring now to ~i~uxe ~, the swi~ches on sewing
machine motor 190 are illus~.rated wherein a switch 192 is
activated as soon as sewlng machine motor 190 is deactivated
to prevent further operation o~ the machine in the sewing
operation. As soon as switch 192 is activated,the handwheel
position lockin~ assembly 198 is allowed to engage a notched
out portion 204 in sewing machine handwheel 162. Handwheel
162 is connected to pulley 196 of the motor 190 via belt 202
which assures the braking of sewing machine handwheel 162 as
pressure is applied to cylinder 212 forcing a stop mechanism
214 into the corresponding notch or notched out portion 204
I
~7~
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in handwheel 162.
In the preferred embodiment of the invention a
~mall positioning motor illu~rated as 220 on mo~or 190 may
be employed to turn motor 190 slowly until stop mechanism 214
is locked into the notch 204 on sewing machine handwheel 162.
Once stop mechanism is engaged in notch 204 on handwheel 162
the needles 100 and 102 along with slitter knife 94 are
removed from the material. The activation of cylinder 212 and
the locking of stop mechanism in notch 204 of handwhe~l 162
actuates switch 222 which extends cylinder 132 of foot
assembly 82 of sewing machine 98 and thereby raises foot
assembly from -the sew clamp assembly 74 and the sewn placket
shirt front, sewn placket liner and placket.
The activation of switch 2Z2 may also be utilized
lS to activate a mi-tre positioning cylinder 236 (Figsi 6 and 10)
which advances the sew clamp 74 to the mitrin~ position for
the mitre cut. Mitre positioning cylinder is associated with
sew clamp by suitable means such as a pinion and rack
assembly associated with sew clamp assembly 74. Sew clamp
assembly includes a positioning bar 228 which suitably
attached to sew clamp 74. Positioning bar 228 includes a
series of holes 230 that are de~igned to be engaged by a
cylinder rod 232 having a cone shaped tip 234 to a3sist in
the engagement o~ one of the predetermined holes 230 on bar
228. The advancement of tip 234 into one of the holes 230 is
assisted by cylinder 236 which when extended activateq a
further switch 238.
Activation of the mitre positicnin~ cylinder 23S in
combination with the mitre positioning means 226 operates to
precisely position the sewn placket shirt front for the mitre
cut. As will be appreciated by those skilled in the art the
engagement of one o the holes 230 by the activation of mitre
-22-
positioning tip 2~4 i5 preset according to the length of the
placket portion of the placket shirt and i5 a critical
aspeot in the manufacture of placket shirts. More
particularly, the positioning of the mitre for the mitre cut
must be within a few stitch lengths in order for the mitre
cut to be properly sriented and positioned on the shirt to
provide a quality placket shirt.
Once mitre positioning means 226 has locked sew -~
clamp 74 into proper position for -the mitre cut switch 238 is
activated energizing cylinder 240 (Fig. 11) forcing a V-
shaped mitre cutting blade 242 down through the placket shirt
front cloth s~d throug~ V-shaped openin~ 24~ (Fi~. 6) in sew j,`
clamp 74 and through shirt body 30 and into a corresponding nylon
insert 246 in table 22 to result in the formation of the
lS wedge shaped mitre cut in the sewn placket shirt front.
Mitre cutter assembly 248 along with nylon insert 246 may be
slideably mounted with respect to table 22 to allow the
adjustment of the mitre to accomodate a variety of shirts.
A slot 250 may be provided in member 252 which may be
attached to sewing machine 98.
In addition to mitring the shirt, switch 238
may be employed to activate the stacker unit 126 (Figs. 6,
7, 12, 13 and 14). Once the shirt has been advanced to the
mitre cut portion the bottom portion of the placket shirt
body 30 (Figs. 7 and 14) is allowed to drop over the hack
end of table 22. Switch 238 may be utilizecl to clamp the
bottom portion 254 of the ~hirt in a shirt clamp formed by
a support 256 of a wedge shaped table 258 mounted on
rollers 260 to ride in tracks 262 to allow the lateral
3G movement with respect to a stationary bracket or bar 264.
The activation of the clamp may be provided by a
cylinder 266 ~Fig. 14) or other available means to
clamp support 256 against bracket 264. As will be
-2~-
discussed in greater detail a means is provided to maintain
constant tension Eor the shirt clamp independent of the
numher of layers of shirts previously stacked on table 258.
Referring now to Figures 13 and 14 the operation of
the stacker unit is illustrated wherein on table top 258 a
number of placket shirt fronts 287 are positioned on wedge
shaped stacker table 258. In the rest position (Fig, 13),
the wedge shaped stacking element is spaced from bracket 264
at a sufficient distance to allow a further shirt front.
bottom portion 254 to be received by the stacker unit 126.
Switch 238 may also be employed before or after the mitre cut
to activate cylinder 266 and thereby clamp bottom portion of ~'~
shirt bodies 30.
Preferably the activation of cylinder 266 occurs
after the mitre cut so that clamping of the shirt bottom
portion 254 results in the activation of a switch 268 which
results i.n the raising of sew clamp 74 to return the se~
clamp to its starting position (Fig. l). Switch 268 which is
mounted to bracket 308 may also be conveniently employed to
activiate a cylinder 284 which is connected to raker bar 282
to pull sewn shirt and threads from sewing machine 98 in
direction of arrow 285 (Fi~.14). After a predetermined
amount of travel the raker bar 282 actuates a switch 283
which activates cylinder 270 (Fig. ll) to drop a wedge shaped
knife 272 to cut the threads pulled from the sewin~ machine
ne~dles lO0 and 102. A mating element 274 is preferably
disposed flush with table 22 and includes a s1.otted opening
in which the s.ides 276 and 278 are razor sharp so when ~he
threads from the machine needles is pressed into the slotted
opening the threads are cut by wedge shaped knife 272~ When
raker bar 282 releases switch 283 it retracts cylinder 270
.. .
~7~
-2~~
movlng wedge shaped knife 272 to its start positi~n so that
when raker bar 282 reaches its full travel in thc direction
o~ arrow 285 (Fig. 14) it actuates switch 286. At this point
shirt body 30 is thereby stacked on a wed~e shaped table 258
over a number of layers of previous shirt fronts 287.
At the end of the travel of raker bar 282 the shirt
is layered and switch 286 is contacted which returns the
xaker bar to its rest position. In returning to the rest
position raker bar 282 contacts a further switch 288 which
results in the unclarnping of the stacker unit 126 and
returning the wedge shaped stacking table 258 back to its
rest position~
The return of the wedge shaped table 258 to
su~stantially the same position in the stacking operation to
result in opening 290 is maintained at substantially the same
distance which is achieved by an adjustable tensioning
means 292 that also assists in maintaining the same amount of
clamping pressure on the shirt fronts irrespective of the
thickness of the layers of the shirt fronts. The adjustable
tensioning means 292 may include a slotted arm 294 in which
a threaded or other cylindrical peg 296 is tensionally
engaged by the action of nuts 298 and 300 and the action of
spring 30Z which allows peg 296 to slide in slotted arm 294
when support ~56 attached to platform 304 with vr without
layered parts 287 applies pressure on stationary bar 264.
The forward travel o~ the slotted arm 29q terminates when
cylihder 266 reaches its full extension. When slotted
arm 294 reaches the end o~ its forward travel the lower
portion of slotted arm 294 contacts switch 268 which
activates sew clamp 74 to raise and also activates sew
clamp 74 to return to its start position. When platform 304
contacts stops 306 platform 304 is reset to its start
position.
~77~
-25-
Upon completion of the stacking of the shirt by the
actuation of raker bar 282 and activation ~ switch 288
terminates the cycle of the stackin~ and clampin~ mechani~m
126 and open~ the clamp so ~hat a ~urther shirt ~ay be
received. The actuati~n o~ a switch 288 may be utilized to
allow the resetting ~ switch 54 gr if already rese~ start the
machine to again activate the transfer clamp ko clamp and
transfer the shirt to sew ~lamp and complete the cycl~ as
heretofore described. It will be recognized b~ those ~killed
in the art that other switching arrangements are possible
such as the return of the sew clamp activating the transfer
clamp to restart the opera~ion even prior to the stacking of
the previous shirt.
Despite the particular axrangement;of switching it
will ~e recognized that the present apparatus and method
requires the opera~or of the machine to only stack the shirt
body, placket, and liner in thei~ proper position and to
initiate the operation of the placket sewing machine to
produce a sewn, mitred, and stacked placket shir~ front
without further manual opera~ion. As a result, much of the
human error, labor and skill heretofore required in th~
manual operation o~ the se~ing of placket shlrt ~xont~ i~
eliminated by the fully automated system of the present
inventlon ~
It will be reco~nized that the advanta~e~ the
method o~ the invention which starts s~wing at or near the
center of the shirt and thereafter sews from the ce~ter up to
the top of the shirt, allows the placket shirt fronts ts be
formed automatically and allows various type~ of sewing
machines to be utilized, such as chain stitch, lock ~titch
and other varieties of sewing machines. Furthermore khe
method and appara~us of ~he presen~ invention allow~ the
formation of precisely sewn and mitred placket shirt ~ront~
-~6~ 7 ~ t~
thereby improving ~he quallty of placket ~hirt fron~s and
reducing the number of ~second~ quality shirts produced.
Production of placket shirt fronts by the method and
apparatus of the present invention is extremely rapid since
the entire cycle of the machine takes about 16 hundredths of
a minute to complete. Consequently about 6 shirts a minute
can be produced provided the operator could keep up with the
apparatus of the present invention.
The present invention is amenable to h wide ranqe
of applications even though it is particula-rly useful in
providing for the production of an automated placket shirt
front apparatus. For example the present method and
apparatus may be utilized in the construction of types of
garments utilizing a placket like shirt opening and for
sewing various styles of garments. The invention is
therefore suscep~able to many mechanical modifications that
could be made by those skilled in the art to utilize the
present method to accomodate a variety of gar~ents by
modifications in the means for lining up and transferring the
garment and modifications in the rack and pinion arrangement
of the sewing machine. The application of the invention to
the variety of operations to which it may be employed
contemplates the modification to include a greater or lesser
number of switches and the simultan~ous performance of a
number of functions either in direct relationship with one or
more of the switches described or the elimination o~ cert~in
~witches. I
In addition, the precise mechanical systems and
their configuration described for the mitring, tran~ferring
and providing for the travel of the transfer clamp, sew
clamp, mitxe and stac~in~ unit, may of course be mod~ied to
.
~ 7~
-27-
suit particular requirements.
It will also be recognized by those skilled in the
art, that ~hile the present system as has heretofore been
described in the preferred embodiment employs a pneuma~ic or
air system for driving the cylinders to perform the variously
described functionsO It will be understood the present
invention may be implemented in a variety of ways such as the
utilization of electric systems, computer-type systems or
othèr t~pes of switching and driving mechanisms and may
utilize a timing mechanism for coordinating the relationship
between the various functions in the operation of the
machine.
It will be further recognized that variations the
placket forming machine and stacker unit may be msde to suit
particular design and manufacturing requirements for various
types of garments. It will further be recognized the
advantages incumbent in the present invention, such as
efficiency of use and the reduction of labor, increased
production and quality of the finished garment may be '
implemented in a number of ways to suit a variety of
manufacturing des,igns and requirements which are within the
contemplation of the present invention~ These and other
modifications and other applications oE the present invention
may be made within the spirit and scope of the invention ~s
defin`ed in the ~ppended claims.
