U.S. patent number 3,589,320 [Application Number 04/851,303] was granted by the patent office on 1971-06-29 for pocket blank sewing machine.
This patent grant is currently assigned to Farah Manufacturing Company, Inc.. Invention is credited to Aubrey G. Beazley.
United States Patent |
3,589,320 |
Beazley |
June 29, 1971 |
POCKET BLANK SEWING MACHINE
Abstract
An automatically operating sewing apparatus having the following
combination of coacting elements to accomplish the sewing of a
pocket blank: means for feeding into a pickup feed position a
workpiece; pickup and transfer means for removing a single
workpiece from the pickup feed position and transferring the same
to a position for feeding to a sewing machine, including holding
means for holding the removed workpiece for feeding said workpiece
to the sewing machine; conveyor means to the sewing machine for
transporting said workpiece thereto including detaching means for
separating from the pickup and transfer means the workpiece held in
the feeding position, and means for feeding the workpiece to the
sewing machine in response to a demand from said sewing machine,
said conveyor means including edge guiding means for guiding the
workpiece toward said sewing machine while said workpiece is being
conveyed towards the sewing machine; means for initial guiding of
the workpiece from said conveyor means into a sewing position;
feeding means for said workpiece during sewing operatively
interconnected to said sewing machine including workpiece engaging
and guiding means operative during said sewing; means for guiding
the workpiece during a sewing operation; sewing slowdown and
stopping means for said sewing and feeding means responsive to a
workpiece position detecting and a sewing control means, including
means to disengage means for guiding the workpiece during the
sewing operation; positioning means for changing the workpiece to
another position and to allow sewing said workpiece in at least one
other direction, said positioning means being operatively
responsive to the interconnected slowdown and stopping means;
conveying means to remove a sewn workpiece from the sewing machine
including accelerating means for severing a thread chain holding
one workpiece to another; means for removing and stacking said
severed workpiece from said conveying means. Employing the above
described apparatus, exceptionally trouble free operation, with
high production rates are obtained without employing complex
constraining devices for the pocket blank and accomplishing the
results by relying on free flowing nature of the pocket blank as as
controlled by properly devised control circuits.
Inventors: |
Beazley; Aubrey G. (El Paso,
TX) |
Assignee: |
Farah Manufacturing Company,
Inc. (El Paso, TX)
|
Family
ID: |
25310458 |
Appl.
No.: |
04/851,303 |
Filed: |
August 19, 1969 |
Current U.S.
Class: |
112/470.05;
112/285; 112/304; 112/309 |
Current CPC
Class: |
D05B
33/02 (20130101); D05B 23/00 (20130101); D05B
33/006 (20130101); D05D 2207/02 (20130101); D05B
65/00 (20130101); D05B 41/00 (20130101) |
Current International
Class: |
D05B
33/02 (20060101); D05B 33/00 (20060101); D05B
23/00 (20060101); D05B 65/00 (20060101); D05B
41/00 (20060101); D05b 019/00 () |
Field of
Search: |
;112/2,121.11,121.12,121.15,10,262,203 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Boler; James R.
Claims
What I claim is:
1. An automatically operating sewing apparatus including a sewing
machine in combination comprising
means for feeding into a pickup feed position a workpiece;
pickup and transfer means for removing a single workpiece from the
pickup feed position and operatively interconnected therewith, and
for transferring the same to a position for feeding to a sewing
machine, including holding means for holding the removed workpiece
for feeding said workpiece to the sewing machine;
conveyor means to the sewing machine for transporting said
workpiece thereto including detaching means for separating from the
pickup and transfer means the workpiece held for feeding to the
sewing machine, and means for feeding the workpiece to the sewing
machine in response to a demand from said sewing machine, said
conveyor means including edge guiding means for guiding the
workpiece toward said sewing machine while said workpiece is being
conveyed towards the sewing machine;
means for initial guiding of the workpiece from said conveyor means
into a sewing position;
feeding means for said workpiece during sewing, operatively
interconnected to said sewing machine including workpiece engaging
and guiding means operative during said sewing;
means for guiding the workpiece during a sewing operation;
means for sewing slowdown and stopping operatively interconnected
to said sewing machine and the last-mentioned feeding means and
responsive to a workpiece position detecting and a sewing control
means, including means to disengage said means for engaging and
guiding the workpiece during the sewing operation;
positioning means for changing the workpiece to another position
and to allow sewing said workpiece in at least one other direction,
said positioning means being operatively interconnected and
responsive to the stopping means;
means for continuing sewing the last seam operatively
interconnected to said positioning means, means for initial guiding
of said workpiece, and means for slowing down and stopping whereby
said positioning slowing down means are rendered inoperative during
the sewing of said last seam;
conveying means to remove a sewn workpiece from the sewing machine,
including accelerating means for severing a thread chain holding
one workpiece to another;
means for removing and stacking said severed workpiece from said
conveying means.
2. The automatically operating sewing apparatus according to claim
1 and wherein the means for initial guiding said workpiece into a
sewing position include means for urging the workpiece for several
stitches against the means for guiding the workpiece during the
sewing operation, means for preventing the upturning of an edge of
said workpiece, and means for lifting a preceding workpiece.
3. The automatically operating sewing apparatus according to claim
1, and wherein the means for guiding said workpiece during the
sewing operation include sewing machine operated means for exerting
a sidewise drag on said workpiece, against a stationary side guide
means for said workpiece.
4. The automatically operating sewing apparatus according to claim
1 wherein the workpiece engaging means operative during sewing
include a drag means engaging the workpiece on a surface thereof
during the sewing operation.
5. The automatically operating sewing apparatus according to claim
4 wherein the drag means are disengaged responsive to the sewing
stopping means.
6. The automatically operating sewing apparatus according to claim
1, wherein the means for sewing slowdown and stopping include means
to sense the end of the workpiece and a stitching line and to vary
the stitching rate responsive thereto by engaging the sewing
slowdown means and stopping means to position in a predetermined
manner the sewing means in a "needle down" position and a "presser
foot up" position.
7. The automatically operating sewing apparatus according to claim
1, wherein the means for feeding into a pick up position said
workpiece holds there at least one workpiece over a vertically
moving lifting means for urging said workpiece upwardly for
removing a single workpiece by said pickup means responsively to a
demand from the sewing means.
8. The automatically operating sewing apparatus according to claim
1, wherein the pickup and transfer means for removing from the
pickup feed position a single workpiece comprises:
first means for holding a supply of adhesive tape,
second means for holding an advanced adhesive tape, said first and
second holding means being located on a common axis;
means for guiding said adhesive tape from said first means over an
end roller positioned on an arm which extends outwardly from said
first and second holding means;
means for oscillatingly rotating said arm between workpiece pickup
position and transfer position and means for holding said arm with
the workpiece being held to the adhesive tape in position for
feeding said workpiece to the sewing machine.
9. The automatically operating sewing apparatus according to claim
8 including the pickup and transfer means for removing from the
pickup feed position a single workpiece and wherein the supply of
adhesive tape is held in a reel, and wherein means for advancing
said adhesive tape consists of an incrementally driven reel, the
means for guiding the adhesive tape over the roller consists of two
rollers axially aligned with the reels, one roller each for taking
from and guiding the tape onto said reels respectively, said end
roller over which said tape is guided is crowned and aligned in its
longitudinal axial midpoint with said reels and said guide rollers,
and the longitudinal axial direction between the guide rollers and
the end roller is perpendicular and wherein the means for
oscillatingly rotating said arm with the end roller is controlled
by a clockwise and a counterclockwise limiting switch riding on a
cam, said cam being on a shaft, and wherein said shaft supports
said reels, arm, the guide means, and cams and is activated by
driving means which oscillatingly rotates the said shaft between
two positions at which the arm comes to rest.
10. An automatically operating sewing apparatus including a sewing
machine, in combination comprising:
1. means for feeding a workpiece into a pickup feed position,
including
a. means for activating said means for feeding, and
b. means for projecting upwardly said workpiece whereby the same is
positioned for transfer to a next feed station;
2. means for pickup and transfer from said pickup feed position of
the single workpiece projected upwardly including
a. means for adhesively securing the single workpiece to said
pickup and transfer device,
b. means for separating said adhesively secured workpiece from
other workpieces in said pickup feed position,
c. means for transferring for a predetermined distance said single
workpiece for conveyance of said workpiece to the sewing machine
upon demand from said sewing machine,
d. means for holding said workpiece in a transferred position until
said demand,
e. means for severing said adhesively held workpiece from said
pickup and transfer means operatively interconnected with means
signaling a demand by said sewing machine, and
f. means operatively interconnected with said pickup and transfer
means to cause said pickup and transfer means to repeat a workpiece
pickup cycle after a removal of a workpiece from said pickup and
transfer means,
said pickup and transfer means being operatively interconnected to
said means for projecting upwardly said workpiece in said means for
feeding said workpiece;
3. means for conveying said adhesively detached workpiece to said
sewing machine, including means for guiding said workpiece by
abuttingly urging the workpiece against an edge guide means which
is oriented in a converging, axially longitudinal relationship with
said means for conveying said workpiece, said means for conveying
having its longitudinal axis positioned in a predetermined location
in respect to the sewing direction of said sewing machine;
4, means for initial guiding of the workpiece into a sewing
position from said means for conveying said workpiece,
including
a. means for sidewise guiding of said workpiece, operatively
interconnected with means for sensing an approach of said workpiece
to said sewing position,
b. means operatively interconnected with means for determining an
approach of last seam being sewn on a preceding workpiece,
c. means for lifting a corner of said preceding workpiece,
d. means for disengaging means for guiding preceding workpiece
during sewing,
e. means for engaging said workpiece with said means for conveying
said workpiece whereby the workpiece is placed in a proper
relationship to said sewing machine for initial sewing of said
workpiece, and
f. stationary umbrella means for preventing the uplifting of a
workpiece corner;
5. means for sewing said workpiece;
6. means for feeding said workpiece during said sewing, operatively
interconnected with said sewing machine during sewing,
including
a. means for engaging said workpiece with said sewing machine,
and
b. means for maintaining the workpiece in a sewing engagement with
said sewing machine operative during said sewing;
7. stationary means for guiding the workpiece during said
sewing;
8. means for slowing down said sewing and feeding means operatively
interconnected and responsive to a means for workpiece position
detecting, including
a. first means for sensing an end of said workpiece, operatively
interconnected to a sewing machine drive slow down means, and
b. means for shifting said sewing machine to a slower stitching
speed operatively interconnected to said first means for sensing an
end of seam and said sewing machine drive means;
9. means for stopping said feeding means including
a. second means for sensing the end of said workpiece, operatively
interconnected to,
b. means for positioning and stopping said sewing machine with a
sewing machine needle in a "down" position, operatively
interconnected to said sewing machine drive means, and
c. means for disengaging said feeding and guiding means,
operatively interconnected to said means for positioning and
stopping said sewing machine;
10. means for positioning said workpiece for sewing said workpiece
in at least one other direction from that of a preceding sewing
direction, including
a. means for pivoting said workpiece around the needle for a
predetermined distance operatively interconnected to said means for
feeding said workpiece during sewing, the first and second means
for sensing the end of said workpiece and the means for sewing said
workpiece;
b. means for reengaging said means for feeding and guiding said
workpiece, and
c. means for reactivating sewing means after completion of said
workpiece positioning means;
11. means for activating said means for positioning said workpiece
for sewing said workpiece whereby a predetermined positioning
sequence is achieved;
12. means for deactivating said means for positioning said
workpiece whereby the predetermined positioning sequence is
terminated including
a. means for continuing sewing after the sensing of the end of said
workpiece by the first and second workpiece end sensing means,
b. means for keeping engaged said feeding means, and
c. means for activating said means for initial guiding of said
workpiece for receiving the next workpiece;
13. Conveying means to remove a sewn workpiece from said sewing
machine including
a. means to detect the conveyance of said sewn workpiece,
b. a partial, rapid conveying section as part of said conveying
means whereby a faster conveying is effected in relationship to the
conveying rate of the rest of said conveying means,
c. engagement means for severing said workpiece whereby the
workpiece is accelerated between said engagement means and said
partial, rapid conveying section, thereby severing a thread chain
joining said sewn workpiece with a workpiece being sewn; and
d. edge guide means for further conveying said workpiece,
14. means for removing and stacking said severed workpiece from
said conveying means including
a. means for detecting the presence of said severed workpiece,
b. means for activating a removal rack to pivot the same
approximately 180.degree. in a direction perpendicularly away from
the conveying means,
c. means for deactivating said means for detecting the presence of
said severed workpiece,
d. means for receiving the workpiece on said pivoted removal rack
whereby said receiving means are lowered progressively upon
stacking each workpiece on the same,
e. means for returning said removal rack to its original position
and,
f. means for activating the means for detecting the presence of the
severed workpiece;
15. means for monitoring the correct operation of said
automatically operating sewing apparatus including means for
signaling a malfunctioning of same.
Description
This invention relates to a repetitive sewing machine operation and
an apparatus therefor whereby a workpiece is sewn successively
along at least two edges thereof and means for effecting the
repetitive sewing by workpiece advancing, positioning, separating
and removing means; more specifically, this invention relates to a
sewing machine in combination with apparatus and means to sew back
pocket blanks used in pants whereby this limpid blank is
automatically advanced, positioned, sewn, separated, and removed
during this operation.
In the production of garments, such as pants, almost endlessly
repetitive sewing operations are required for a competitive
manufacture of these garments. Thus, for example, in the
manufacture of pants, such as pants for men, the back pockets are
fashioned from a pocket blank which undergoes a number of
manufacturing steps until it is incorporated into the finished
pants article.
As part of this operation, and after the back pocket blank has been
cut, it is folded, a facing may be sewn on it, and then this blank
is stitched along three edges to form a pocket pouch. In sewing
along the edges of this blank, at the two bottom corners of this
pocket, approximately 90.degree. turns must be made. Moreover, the
pocket may not be fashioned as a perfect rectangle, but rather the
edges of the pocket may be slightly curved.
A number of steps are performed in the sewing operation of these
pocket blanks, and heretofore manual labor has been utilized to
produce these semifinished articles. Consequently, the cost
component attributable to manual labor in this semifinished article
is rather high. Despite the endlessly repetitive nature of each
operation and the incentive to reduce the cost of the semifinished
article because of the repetitive operation, it has not been
possible to do so; and the cost because of the high labor component
in this article has remained high.
Previous art attempts to accomplish serial and successive
operations on various blanks are, as a general rule, inapplicable,
as these attempts have been directed to performing sewing
operations on different workpieces which have required an entirely
different arrangement of sequential operations. Moreover,
conceptually, these different machines are unrelated, as each
workpiece, because of the almost endlessly repetitive nature,
prevents the utilizing of the machines designed for any other
operation. Although, in an isolated context, some of the machines
used in performing repetitive sewing operations may appear related
because of repetitive sewing operations, upon further analysis, it
is evident that the total combination used for each workpiece
consists of differently coacting elements, and, hence, each
combination is driving towards a different end result. Moreover,
the prior art devices have often employed clamps, e.g., frames and
belts to constrain a workpiece blank. These constraining devices
have required ancillary indexing means. As a result, a multitude of
cams, indexing gears, engaging devices which rely upon belts,
chains, shafts, etc. have introduced, for these operations, an
intolerable mechanical complexity for achieving a simple
result.
Therefore, it has been a desideratum in the repetitive sewing
operations to achieve a simplified, faultless, trouble-free, and
freely-flowing sequential operation which can be carried out at a
high rate of operation with a minimum of manual labor component
when acting on a single item.
It has now been found that the actual sewing operation of certain
endlessly repetitive steps performed on the same type, or
substantially the same type, of workpiece can be accomplished in a
superior manner when compared to the best machines heretofore
known, or even the most skilled manual labor, by means of a sewing
machine when the same is operated in a combination utilizing the
freely flowing nature of a limpid workpiece blank and when the
operation is carried out with interrelated means which advance,
position for sewing, sew, and remove from the sewing zone the
workpiece, i.e. the partially finished back pocket blank.
It has been further found that a novel adhesive tape workpiece
transfer device has been especially noteworthy as an element in
this combination assuring reliable, demand-originated flow of the
limpid blank upon which the sewing operation is performed. This
transfer device provides a simple and uncomplicated means for
advancement of imprecisely aligned workpieces.
Still further, it has been found that a novel combination of guide
and positioning means in conjunction with the pickup and transfer
means enable the advancing of a workpiece to the sewing zone in a
trouble-free manner without interference with the preceding
workpiece while the latter is being sewed. Moreover, it has been
found that a combination of rigid guides, in cooperation with
actuatable guide devices, operated in conjunction with the sewing
machine drive means, presser foot, feed dog and needle provide a
unique sequencing device for performing sewing operations having a
plurality of approximately 90.degree. turns on a particular
material.
Additionally, it has been found that the workpiece stitch chain
formed during the sewing operation can easily be broken by a
workpiece severing means disclosed herein and the severed workpiece
removed after this severing operation in a facile, trouble-free
manner.
Various other advantages of this invention will be pointed out or
will be apparent from the further discussion of the invention in
reference to the drawings.
A smoothly flowing workpiece handling has now been achieved in
respect to pants pocket blanks with a machine as further described
herein and in reference to the drawings wherein the same elements
or elements functioning in equivalent manner have been designated
with like identifying numbers and wherein:
FIG. 1 is an isometric view of the novel machine in combination
with the advancing, positioning, sewing, and removing means which
perform the complete work cycle in the sewing of a pants back
pocket blank;
FIG. 2 is a top view of an adhesive tape transfer device in the
combination illustrated in FIG. 1;
FIG. 3 is an end view of the pocket blank conveyor illustrating the
pocket blank removal roller for separating the pocket blank from
the adhesive transfer device along line 3-3 in FIG. 2;
FIG. 4 is a side view in section of the adhesive tape transfer
device and the cooperating lifting bar mechanism along the line 4-4
in FIG. 2;
FIG. 5 is a top view of a sewing table showing the work guiding,
positioning, and severing means in the operation of the sewing
machine;
FIG. 5a is a section of FIG. 5 along line 5a;
FIG. 6 is a section 6-6 of FIG. 5 and a detailed illustration of
the side guide idler roller means in the initial sewing
operation;
FIG. 7 is a section 7-7 of FIG. 5 and is an end view towards the
head of the sewing machine illustrating the guiding means around
the sewing machine presser foot;
FIG. 8 is a top view of the workpiece removing device;
FIG. 9 shows the left end view of workpiece removing device of FIG.
8;
FIG. 10 is a section 10-10 of FIG. 8 and illustrates the stacking
table; and
FIG. 11 is a section line 11-11 and illustrates the standing table
with the guide means therefor;
FIG. 12 is a schematic diagram illustrating the manner in which
FIGS. 12a through 12i should be arranged to form a complete circuit
diagram;
FIGS. 12a through 12i together comprise a circuit diagram
illustrating the operation of the machine shown in FIG. 1.
GENERAL DISCUSSION OF THE APPARATUS
In reference to FIG. 1, the apparatus illustrated therein consists
of a belt conveyor 1 upon which the precut and prefolded fabric
blank 2 is placed. This blank is also illustrated in FIG. 2 and in
FIG. 8 in finished form. As the bundle of blanks is advanced, each
blank, either individually or one resting on top of another, is
urged onto lifting bar 3 by means of conveyor belts 4. The lifting
bar is actuated when the adhesive tape pickup and transfer device 5
with arm 6 has swung 90.degree. in a position in which arm 6 is
directly above lifting bar 3. In reference to FIG. 2, upon being
lifted by the lifting bar 3, the blank 2 attaches to an adhesive
tape 7 which is pressed to an adhering contact with the fabric
blank when the lifting bar with the pocket blank on top of it moves
against the same adhesive tape. The adhesive tape transfer device
is actuated when the pulley 12 removes the blank being held over
the roller conveyors 57a. Photocell 8, when it senses no blank in
the path of an actuating lamp 9, advances the conveyor belts 4 to
keep a supply of blanks on the lifting bar 3.
After the adhesive pickup of the blank by the pickup device, this
blank is swung 90.degree. clockwise with the blank securely
dangling from the adhesive tape and transferred over to an input
conveyor 57a. Thus, this blank is held over continuously rotating
and sprocket- and chain-interlinked conveyor rollers 10 forming the
input conveyor 57a.
When the sewing machine 11 is about ready to receive the next
blank, a puller wheel 12 is actuated, and when the puller wheel 12
slightly engages the fabric blank 2, a conveyor roller 10a detaches
the blank from the adhesive tape 7 and feeds it along an input path
on conveyor 57a.
As the conveyor rollers transport the limpid fabric blank 2 towards
the sewing machine 11, i.e. towards the input side thereof, a guide
rail 13, on the surface of the input conveyor 57a which rail is at
a diverging angle to an imaginary line perpendicular to axis of
rotation when viewed towards the sewing machine 11, guides the
fabric towards the sewing machine as the conveyor rollers 10 urge
the blank snuggly against the rail. The length of the conveyor and
the rotating velocity of the rollers can be appropriately adjusted
if needed.
A side guide 14, oriented vertically on a highly polished sewing
table 15, is placed again at a slight angle from that defined by a
normal feed direction of the sewing machine, which, in this
instance sews straight. The side guide 14 urges the fabric blank 2
being sewn away from the straight line and away from the sewing
machine head 111. This gentle urging aids in keeping the stitch
pattern at a uniform distance from the edge of the blank.
However, an additional guide means is required because, in
practice, the guiding action favors holding the pocket against the
output side of the side guide 14 more than against the input side
of the side guide 14, and as a consequence of the sewing machine
feed dogs 112 being located adjacent to the output side of the
guide. It was found that if a drag were introduced on the limpid
fabric blank 2 on the input side of the side guide, the proper
feeding was achieved. A drag of the necessary kind is obtained by a
drag roller 115, such as illustrated in FIG. 1. Other equivalent
means but which are less preferred are rollers, belts, or other
friction devices.
In addition to the previously discussed guide means consisting of
guide rail 13, side guide 14, and drag roller 115, a further guide
means is needed, it is conveniently in the form of an idler roller
16. Its axis of rotation is askew to the perpendicular axis of
rotation of the next to last conveyor roller 10b on the input
conveyor 57a. A brief explanation is as follows: as the sewing
machine presser foot 113 comes down on the incoming and unsewed
blank 2, this idler wheel 16 makes a low pressure contact on the
trailing edge of the incoming blank 2 by pressing it against the
conveyor roller 10a. This action causes a sidewise urging of the
blank and acts as a necessary "guiding hand" during the first few
critical stitches. After these stitches, the idler wheel 16 is
retracted and the subsequent sewing of the blank is accomplished
without the aid of this idler wheel 16.
The actual sewing is carried out by lowering the presser foot 113
on the incoming blank and effecting the continuous guiding of the
pocket blank 2 by the side guide 14 and drag roller 115. As the
first stitch passes along the first, longer side of the blank and
is nearing its end, the photocell 19 sensing the end of the blank
slows down rapidly the sewing machine for the last few stitches on
that side so that the machine can be prepared for controlled
stopping in a "needle-down" position when photocell 20 senses the
end of a blank. When the last photocell stops the machine in the
"needle-down" position, the presser foot 113 is raised.
A demand for a new blank is signalled by a photocell 19 when it
senses no interruption by a sewn blank after having accounted for
the previous two stitching passes.
This slowing down is needed because the machine cannot be stopped
accurately in the "needle-down" position while it is running at its
conventional stitching speed. This slowed down speed of sewing is
called "inching speed" hereafter. Thus, as the machine is running
at inching speed, the photocell 20 detects the end of the blank
(bottom of pocket) and stops the machine.
The needle 21 is now at an equal distance from the edge of the
pocket blank at the side and bottom of this blank. At this time,
the sewing machine presser foot 113 and the drag wheel 115 lifts.
The blank 2 is now free from all means engaging the same save for
the needle 21 which is piercing its corner.
At this juncture, a pocket turner rod 22 having an umbrella lip
extension 222 on a sliding block 221 is actuated causing the pocket
blank 2 to rotate 90.degree., pivoting the blank on the needle 21
in its down position. The side guide means against which the pocket
blank is urged has a semicircular segment space 142. Upon turning
the blank 2, this segment space 142 allows the necessary clearance
for a pocket blank's corner.
The sewing sequence previously explained is repeated as the sewing
machine 11 sews along the bottom (which is about one-third of the
distance along the side) and the other side of the pocket, the
pocket turner rod 22 effecting the second 90.degree. change of the
pocket at the next corner. The control means which sequence and
permit this operation are explained further herein.
As the pocket blank is sewn along the last side, the sewing
operation instead of signaling another turn continues because a new
pocket blank is already in place ready to be sewn. This sequence
again is achieved with the timing devices provided herein and as
discussed with respect to the circuit control. However, two items
of consequence must be met for effective handling of the incoming
blank. First, the machine should continue sewing at its high sewing
speed, thus forming a thread chain 58. Second, because of the
geometry of the formed blanks, the incoming blank and the finished
pocket blank overlap and would engage each other if it were not
prevented in accordance with the invention herein.
It is necessary to prevent this overlap as the finished pocket
would drastically alter the sewing pattern for the incoming blank.
Thus, to prevent the trailing edge of the finished blank from
engaging the leading edge of the new pocket, a pocket corner lifter
cylinder 23 is projected vertically, for example by suitable means,
such as a pneumatically activated rod or cylinder 231, just before
the new pocket would have made contact.
As soon as the new blank is trapped by the sewing machine presser
foot 113, the rod 231 is retracted promptly. The finished blank is
still attached to the blank being sewn by thread chain 58.
In order to separate these blanks, the thread chain 58 must be
broken. It is accomplished by having a conveyor roller 10c geared
to run several times faster than the other rollers and activating a
double wheeled forcing roller 24 and to press against the rapidly
rotating roller when the proper distance is observed by a photocell
56. This action accelerates the pocket and breaks the thread chain.
As the finished blank interrupts the light beam of photocell 25 at
the end of the conveyor, it activates a stacking arrangement
consisting of a stacking gridiron 26 which fits between the roller
conveyors 10. A pinion 27 is activated such as by pneumatic means
illustrated by a cylinder 28 pushing a suitable rack 29. A motor 30
which may be of the same make as 39 (described hereinafter) with a
pinion 31a and rack 31b drops the receiving table 32 on each
transfer of a new blank for a distance equivalent to the thickness
of a blank.
As the pneumatic system is based on directly piped fluid under
pressure, as this system is controlled by appropriate solenoid
operated valves placed in the fluid lines and as this system does
not perform independent functions in the present device, the piping
for this system has not been shown. However, the circuit diagram
illustrated herein show the necessary valves which are activated by
the appropriate circuit elements.
A more thorough discussion of the various cooperating elements of
the invention will now follow in conjunction with the further
amplification of the subject matter disclosed in the drawings
depicting each of the elements of the combination.
BELT CONVEYOR
In reference to FIGS. 1 and 2, the belt conveyor 1, which advances
the fanned out pocket blanks, has three V-formed belts 4, as the
conveying means. These belts are trained around pulleys on shafts
4a and 4b either of which can be driven by a motor. A suitable
motor is the same as 39 used in the base of the pickup and transfer
device 5.
It has been found useful to have the belts 4 slightly recessed but
still protruding above a plane formed by the surface of the
conveyor table elements 4c. At the end of belt conveyor, abutting
and overlapping the right-hand or input-side of conveyor structure
57a is a U-shaped combination guide-table 4d, in which the two legs
are pointing away from conveyor 57a and which has upturned edges 4e
at both sides. These edges 4e are tapering to become level at the
table portion of the guide table 4d, i.e. at the end abutting or
proximate the input conveyor 57a. The table end 4d of the
table-guide if made of the same piece of metal is polished and
curved slightly downwardly towards the rollers 10 to minimize the
dragging friction of the pocket blank 2 when it is pulled over the
guide-table 4d and onto the rollers 10. However, if the table
portion of the guide is made of a separate piece it curves
downwardly towards the guide-table 4d as well as towards the
rollers 10 overlapping slightly the last.
In order to provide sufficient space between the table elements 4c
and the belts 4 for the lifting bar 3, the end portion of guide
table 4d is made sufficiently narrow to accommodate the lifting bar
3. Further, the shaft 4b is placed slightly below the guide table
element 4d to disengage the front part of the pocket blank 2,
before the blank is urged further onto the guide-table 4d and over
the lifting bar 3, by the conveyor belts 4. The guide-table 4d may
have the downwardly curving portion of it which is overlapping the
input conveyor 57a made as a separate piece.
In FIG. 1, the box 101 placed longitudinally next to the belt
conveyor 1 contains the electrical circuit elements for the
conveyor 1, the pickup and transfer device 5, and additional
pneumatic conduits and valves used with these devices as further
described herein. The other electrical circuit elements as well as
the pneumatic devices are enclosed in the box identified in FIG. 1
as 102 and placed alongside the output conveyor 57b.
PICKUP AND TRANSFER DEVICE
In reference to FIG. 2, the adhesive tape pickup and transfer
device 5 will now be discussed as it is used for placing the pocket
blank 2 on the input conveyor 57a with the aid of the lifting bar
3.
The pickup of the pocket blank and transfer of it is effected by
the transfer device 5 (hence, a pickup and transfer device)
consisting of an upper tape reel 33 which is free to rotate around
an axis 34 of the transfer device 5. A lower wheel 35 rotates
around axis 34. The adhesive tape 7 is unwound in small increments
or continuously at very low rate from the upper tape reel 33 by
winding it on lower tape reel 35 which is driven by means of a
motor 38 through a very slowly turning gear train 37 driving the
reel with belt 36.
As previously discussed, the pickup and transfer arm 6 of the
transfer device 5 rotates through 90.degree. in a clockwise and
counterclockwise direction by means of a motor 39 in the base of
this device.
This motor is appropriately actuated by a signal from the puller
wheel 12 when the puller wheel 12 removes the previous blank. This
blank is held by the pickup and transfer arm 6. The adhesive tape 7
is sufficiently "sticky" to hold the blank over the conveyor 57a
while the rollers rotate at full speed.
Upon actuating the motor 39, it swings, counterclockwise, the
pickup and transfer arm 6 to a predetermined position over the
lifting bar 3 over which the motor 39 is automatically stopped. The
appropriate stop position is determined by a counterclockwise
limiting switch 40 riding on a raised counterclockwise limiting cam
41 fixedly and nonrotatingly attached to a shaft 45 holding the
pickup and transfer device 5. The switch 40 is deactivated by a
depression in the cam at the end of the swing. When the
counterclockwise rotation stops, the lifting bar 3 is actuated.
This bar is covered with an elastomer, such as sponge rubber 442,
and it lifts upwardly the several layers of the fanned out pocket
blanks by means of one or two lifting bar cylinders such as the
illustrated single cylinder 44 guided by rods 441. The cylinder,
upon retraction, activates the motor 39, and it returns the arm 6
over the conveyor rollers 10 with the motion being stopped by a
clockwise limit switch 42 activated by a clockwise cam 43 and
affixed nonrotatingly to a sleave and in turn to the shaft, the
same as cam 41. These two switches 40 and 42 are affixed to a
housing 49 which rotates around the shaft and is driven by motor
39. These switches make contact when riding on a raised cam. Of
course, these same switches may also make contact when riding on a
cam depression.
The motor 39 which drives the pickup and transfer assembly is
attached to a shaft 45 at the base of a pedestal 46 housing the
shaft 45. The respective positions of the device 5 are illustrated
in FIG. 2 by the dashed lines. This motor is reversible, and in
cooperation with switches 40 and 42 turns 90.degree. in either
direction. The motor 39 has substantially no coasting
characteristics, i.e., it can be stopped in a predetermined
position with an error of about .+-.1.5 angular degrees. A
representative motor is SS50PIRC available from Superior Electric
Company, New Britain, Connecticut.
The adhesive tape 7 is carefully guided onto the free riding guide
pulleys 47 disposed vertically to the line of travel of the tape
and then, by imparting a 90.degree. twist, the tape is guided over
a rimless but crowned guide pulley 48 which has its rotating shaft
affixed to the pickup transfer arm 6 about perpendicular to the
axis of rotation of the conveyor pulleys and with the lower edge of
the pulley 48 protruding below the arm 6. The positioning of the
respective tape holding and guiding elements is on a line through
the middle of the perpendicularly transverse axis of pulley 48, the
middle of longitudinal axes of pulleys 47, and the middle of the
axes on which the tape reels 33 and 35 are rotating, thus giving
the best operating characteristics for keeping the tape operating
smoothly and without overriding. Generally, the tape 7 is advanced
only during the counterclockwise swing of arm 6 by an appropriate
increment.
Experience has shown that it is sufficient to advance the tape by
about 1/32 inch during this swing. As the motor 38 is geared to
rotate the tape advancing reel very slowly, it may be run without
interruption during the operation of the machine, or it may be
stopped for a given period during each cycle. The upper housing 49
of the pickup and transfer unit including the motor 38 oscillates
with motor 39 when the last drives the central shaft 45.
FIG. 3 shows an end view of the pocket blank conveyor 57a with a
conveyor roller 10 and the adhesive tape 7 holding a pocket blank 2
which is removed from the tape 7 when the puller wheel 12 is
actuated by the pneumatically driven cylinder 50, spring loaded to
reside in the up position. Once detached, the blank travels towards
the sewing machine on the input conveyor 57a.
Turning now to the cross section of the pickup and transfer unit as
it is represented in FIG. 4, it is seen that the lifting bar 3
generally has at all times on it a few pockets. The bottom edges of
the pocket blanks 2 (bottom of pocket) are resting on the lifting
bar 3 in the depicted orientation. As different thickness of the
pocket blanks are encountered, such as when material of different
thickness is used or when a facing cloth is present on the inside
of the pocket blank, it makes the stack or bundle uneven. Hence,
this depicted lifting action and orientation of the blanks is
needed for the successful operation of the machine. For this reason
also, the pickup and transfer device 5 is considerably simpler and
easier to operate than a single piece pickup device, such as
illustrated in U.S. Pat. No. 3,386,396, June 4, 1968. Of course,
the operation of the lifting bar 3 and the pickup and transfer
device 5 is interrelated and it is further explained in detail in
the section dealing with the control circuit. However, equivalent
lifting means in place of the pneumatic cylinders 44 may be
employed, such as cams, racks and pinions, wheels connected through
a pitman lifting the bar, etc. Similarly, the tape drive mechanism
may be provided with a ratchet mechanism and keyed to the
90.degree. oscillating motion of the drive shaft 45 as provided by
gears coupled to the motor 39.
WORKPIECE GUIDING, POSITIONING, SEWING, AND SEVERING MEANS
Turning now to a more detailed discussion of the sewing operation
and the proper positioning of the workpiece, i.e., the back pocket
blank, FIG. 5 depicts a top view of this subcombination of
elements.
First, the sewing machine 11 which is employed is of the
conventional type, such as Singer 281 or a similar machine in which
sewing walks the fabric through the machine to generate a stitch
pattern by the use of feed dogs. However, various modifications are
employed in the operation of this machine in respect to the fabric
guide means.
A. GUIDE MEANS ASSOCIATES WITH CONVEYOR 57a
Thus, after the pocket blank 2 has been detached from the adhesive
tape, this blank 2 is guided by the conveyor rollers 10 (which are
drivingly connected by chain belts, or gears to each other and to a
motor not shown and generally run continuously). As the blank moves
towards the input side of the sewing machine 11, it is urged
against a guide rail 13. As previously explained, the guide rail 13
is at an angle of about 2 to 3 but preferably 2.5 angular degrees
to a line perpendicular to the rotating axis of the rollers 10. Of
course, the angle may be varied. In turn, the line perpendicular to
the rotating axis of the conveyor rollers 10 is directed at a
slight angle, i.e. on the same order towards the feed dog, i.e. at
an angle opposite from that of the side guide 14 and about the same
order of magnitude as for rail 13.
A pneumatic cylinder (not shown) may be provided on the input side
of the conveyor 57a attached to the guide rail 13 for vibrating
slightly the conveying mechanism in the event the limpid fabric is
stuck or is not advanced satisfactorily.
As previously discussed, for convenient handling as well as
achieving proper timing sequence, an input angle of the input side
conveyor 57a may be selected which is generally suitable. Moreover,
the rate at which the conveyor rollers 10 are rotated as well as
the length of the conveyor, i.e. the total number of rollers, may
be selected to provide for the best operating conditions.
The advantages accruing by the use of guide rail 13 will now be set
forth because the operation of the guide rail has not been
explained above. Fist, by employing the guide rail 13, the fabric
blank 2 does not have to be placed in a precise manner on the
rollers; secondly, it need not be so placed and then gripped with
top and bottom belts as to insure immediate alignment. Moreover, as
a consequence of this gently varying alignment, the blanks resting
in a stack or bundle on the belt conveyor 1 can be placed on the
conveyor rolls 10 in misaligned positions. As mentioned before,
this element with other elements in combination renders the present
device considerably more simple, relatively speaking, from a device
such as disclosed in U.S. Pat. No. 3,386,396.
B. POSITIONING AND GUIDE MEANS ASSOCIATED WITH SEWING MACHINE
DURING SEWING
Referring to FIGS. 1, 5, 6 and 7, the incoming back pocket blank 2
after leaving the side guide rail 13, which may also be formed as
an angle iron with one leg of the angle as an umbrella over the
conveyor rollers 10, proceeds unto the sewing table 15. This table
is a highly polished metal plate with three downcurving edges,
except for the edge towards the machine which is level with the
sewing machine work bed 11a; this table 15 has a stationary side
guide 14 positioned on the top of it. Preceding this side guide 14
is a catch hood 52 which is curved upwardly towards the rollers 10
from which it receives the incoming blank. This hood 52 is in the
form of a segment from a flat disc with the edge towards the
machine tapering downwardly and a flat central plane of the disc
being the upper surface of the catch hood 52 the curved portion of
the disc facing downwardly towards the table 15.
The function of the hood 52 is to prevent the upturning of corners
of a new blank being received on the sewing table 15 or when
turning on this table 15 the blank 2 through a 90.degree. angle at
the two corners of the blank.
As the outgoing and sewn blank leaves the table 15 after the sewing
operation, the geometry of the particular blanks may be such as to
overlap at the trailing corner away from the needle 21 before
sewing can begin on the new blank. For this purpose, a pocket
corner lifter 23 is provided which is activated by sensing of the
incoming blank by the photocell 19. This lifter rod 23 is activated
by a pneumatic means such as cylinder 231 through a solenoid valve
appropriately interconnected to the control circuit as further
explained herein. The lifter rod 23 is retracted immediately when a
properly programmed signal is received, i.e. when the new blank is
trapped for sewing by the sewing machine presser foot 113.
The means effecting a trapping of an incoming blank cooperate as
follows: After the new blank goes under the hood 52, the roller
drag 115, which is canted at about 10 angular degrees towards the
line defined by the sewing machine when stitching, engages the
blank.
The roller drag wheel 115 and its assembly is illustrated in FIG. 5
and in cross section thereof in FIG. 5a in more detail. The support
axis 115a upon which the roller rotates and is pivoted for
disengagement from a blank is shown as it rests on a support 115b
beyond the side guide 14 on the sewing machine 11 table. A fulcrum
arm 115c projecting below the support axis 115a of the roller drag
wheel provides a surface upon which a rod from a pneumatic cylinder
115d extends to overcome the spring 115e which normally holds the
drag wheel 115 down. The spring 115e is adjusted, by appropriate
means such as a screw and/or eyebolt attached to the upper arm 115f
of the housing, for proper tensioning and, thus a variable drag
effect by wheel 115. The roller drag wheel 115 is activated by the
means further explained in the description pertaining to the
electrical circuits. For the understanding of the mechanical
operation, it suffices to mention that the roller drag 115 is
lifted when the presser foot 113 is lifted for pivoting the blank
about the sewing machine needle 21. This roller drag 115 can be a
knurled roller, wheel, or a friction type device, and adjusting its
drag angle with respect to the direction of pocket travel will
optimize the guiding characteristics. The drag roller 115 is found
to be especially useful as the output side 141 of the side guide 14
is adjacent to the sewing machine feed dogs 112, and the added drag
induces the pocket to fit snugly against the side guide 14
preventing the feed dogs to move the pocket away from the guide. In
addition, this drag coacts with the action exerted by the feed dogs
112, urging the blank against the side guide 14 which is at a
slight angle away from the parallel line to which the feed dog
would urge the blank if the same were not restricted by the side
guide 14 (which is conveniently in the form of a polished metal
surface).
Further, as the incoming blank 2 needs to be very carefully guided
for the first few stitches and as the curvature of the blank 2 in a
free laying condition requires very careful handling of the pocket,
a side guide idler roller 16 is provided which is lowered just as
the sewing machine presser foot 113 comes down and traps the pocket
blank 2. The idlerwheel 16 axis is askew to the axis of rotation of
the next to the last roller 10b. This arrangement consists of a
wheel lever 16a held in a "wheel idle" position by a spring loaded
cylinder 53 with an extending rod in which the cylinder rod holds
the lever 16a depressed and wheel 16 raised. This wheel 16 is
suspended and held above the roller 10b at a fulcrum point 54 and
the wheel 16 engages the incoming blank when the air cylinder rod
53 retracts. After a few stitches, the idler wheel 16 is disengaged
when a spring (not shown) retracts the cylinder rod 53.
It is to be noted that the pocket blanks may be sews either face up
or face down.
C. POSITIONING MEANS FOR POCKET BLANKS DURING TURNING THROUGH
90.degree.
Proceeding now to the machine elements which cooperate in the
facile turning of the pocket blank, it is noted that two
approximately 90.degree. turns must be made at the end of two
stitch lines; and these turns must be made with great precision for
the particular pocket blank 2. Although the angle of turning is
approximately 90.degree. for the herein described pocket blank, the
apparatus can be employed for different angles by proper change of
the elements of this subcombination. The means for effecting the
turns is illustrated in FIGS. 1, 5 and 7 and works as follows:
After the guiding means and feed dogs 112, which were discussed
above in conjunction with the sewing machine, have fed the pocket
blank to near the end of the first line of stitches, the photocell
19 detects the end of the blank and activates appropriate means (as
further explained below) to shift the sewing machine 11 to an
"inching" speed (the machine motor is running at approximately
3,450 r.p.m.) the inching speed motor runs at about 400 r.p.m. The
sewing machine slowdown means, i.e. the means to shift down from
the high speed to "inching" speed is accomplished via a clutch
which disengages a sewing machine motor connected to conventional
sewing machine drive means and engages a brake wheel which is also
a geared wheel driven by a small motor rotating at about 400 r.p.m.
This "slow-down" device is readily available on the market such as
from American Safety Table Co.
This inching speed prepares the machine by activating appropriate
control devices described in respect to the circuit for accurate
stopping with the needle in the "needle-down" position. Thus, when
the inching motor is running at 400 r.p.m., a needle positioning
device (not shown) is activated which senses the correct needle
position and upon a proper signal as further explained herein
through dynamic braking of the inching motor, i.e. reversing the
direction of rotation of the same, slows down the sewing machine
with the needle in a properly positioned place. This needle
positioning device is known in the art and is available such as
from American Safety Table Co. As the machine is running at inching
speed, the photocell 20 detects the end of pocket blank and
activates through the herein described control means the above
mentioned device for positioning the needle 21 in its down position
and stops the machine at an equidistant point from the two edges of
the blank. A proper adjusting of the photocell 19 and 20 positions
insures the correct stopping distance. In operating the present
sewing machine, the presser foot 113 is lifted by a pneumatically
activated piston rod 116 acting on a lever 113b overcoming a spring
(not shown) holding the presser foot 113 in the down position. A
hand operated presser foot lifting latch 113c shown in FIG. 1 is
also provided which lifts and holds in a "presser-foot up" position
the end of lever 113b. These presser foot lift means are well known
in the art. A switch 113d is placed beneath the lever 113b which
senses the "presser-foot up" as well as the "presser-foot down"
positions. The operation of this switch in conjunction with the
machine control will be explained further in connection with the
discussion of the circuit diagram.
When the sewing machine 11 stops the sewing, presser foot 113 is
lifted by means of the pneumatic cylinder 116 as described above.
At the same time, the air cylinder shown in FIG. 5a lifts the drag
roller 115 from the table. The needle 21 is now used as a pivoting
point. The pneumatically activated pocket turner rod 22 extends and
pushes the blank 2 thereby pivoting the blank 90.degree.. At the
rod end there is provided a plastic block 221, appropriately shaped
and angled, which slides on the polished table 15 and has an
elongated lip 222 extending from the top part thereof. The length
of cylinder rod stroke is adjusted for any appropriate turning
angle, i.e. 90.degree. for the illustrated blank. As the pocket
turner rod 22 retracts, the presser foot 113 and drag roller 115 go
down. The sewing, guiding and turning is now accomplished in the
same manner as explained above.
As discussed below, by means of an appropriate circuit arrangement,
the last line of stitching is continued beyond the end of the
pocket with the first edge of the incoming pocket blank being sewn
in one continuous motion. The operation of the guiding mechanism
including the pocket corner lifting rod 23 was explained
before.
THREAD BREAKER FOR SEPARATING TWO POCKET BLANKS
The thread breaker arrangement consists of a double forcing wheel
24, photocell 56 and a roller 10c. These are shown on FIGS. 1 and
5. The roller 10c, located beneath the thread breaker wheel 24 is
geared to turn about several (e.g. three) times faster than the
other rollers 10 on the removing conveyor 57b. As a pocket blank is
moved down the conveyor 57b and it interrupts the thread breaker
photocell 56 path, it is still attached to a next pocket being sewn
by the thread chain 58. Referring to the circuit discussion
illustrating this operation, when the appropriate control circuit
means are activated by the detecting photocell 56, the pneumatic
cylinder 58 which drives the double forcing wheel 24 down traps the
pocket between the double forcing wheel 24 and the faster rotating
roller 10c thereby accelerating the pocket and breaking the thread
chain 58. The pocket being sewn is not affected since it is held
firmly in the sewing machine 11 by the sewing machine presser foot
113 and the feed dogs 112. The length of time during which the
double wheel 24 is forced down is suitably selected by employing
the proper electrical components in the control circuit. The
removing or output conveyor 57b may have a similar guide means as
the guide rail 13 provided for input conveyor 57a.
POCKET REMOVAL AND STACKING ARRANGEMENT
After the double wheel forcing roller 24 severs the thread chain
58, the pocket blank is conveyed to the end of the removing
conveyor 57b as illustrated in FIGS. 8, 9, and 10 and 11 and
detected by photocell 25 which activates the stacking rack or
gridiron 26. This gridiron consists of a number of rods 261 of a
thickness which allows the same to fit between conveyor rollers 10
which are spread out slightly to accommodate these rods. In turn,
these rods 261 are introduced into an axis 262, which is in a
journal bearing 262a at either end of the axis 262. The axis 262 is
provided with a pinion 27 on one end thereof. At the other end of
the axis is a counter 263 as shown in FIG. 1. The stacker gridiron
26 is provided with an angle shaped side holder 264 to which the
rods 261 are affixed. Upon activating the rack 29 by means of a
double acting pneumatically operated cylinder and rod 28, the
stacking gridiron swings through 180.degree. angular degrees with
the pocket being held in place by the centrifugal force on a side
holder 264 to which the guidiron rods 261 are attached. A motor 30
driving a pinion 31a on a rack 31b moves the stacking table 32
downwardly for a predetermined distance equivalent to the thickness
of a single blank each time the stacking gridiron is activated. As
illustrated in FIGS. 10 and 11, appropriate guiding wheels 321
surround the rack 31b which rack also forms the columnar supporting
means for the stacking table 32.
DISCUSSION OF ELECTRICAL MEANS AND CIRCUIT DIAGRAM
ELECTRICAL CONTROL SYSTEM
FIGS. 12A through 12I of the drawings together comprise the
complete schematic circuit diagram of the electrical system for the
machine of the present invention. FIG. 12 is a schematic diagram
illustrating the manner in which FIGS. 12A through 12I should be
interconnected in order to form a complete circuit diagram.
The initial conditions which will be assumed for the purpose of
describing the circuit are that the machine has just sewn a pocket
but is not processing pockets at the moment, and a pocket is
attached to the pocket pickup and transfer unit and is being held
over the input conveyor rollers. The operation of the control
system will be explained starting with the movement of the pocket
blanks along the belt conveyor 1 and ending with the stacking of
the completed pockets at the opposite end of the machine. All
switches are shown in their normal positions in the drawings unless
it is stated herein to the contrary. The symbol "H" is used in the
drawings to indicate an AC source having a voltage of 120 volts
with respect to ground.
A. BELT CONVEYOR CONTROL CIRCUIT
As it has been mentioned above, the belt conveyor 1 keeps a stack
of pocket blanks in position to be fed into the sewing apparatus.
Referring now to FIGS. 1 and 12B, when light from the lamp 9 is
permitted to reach the photocell 8, the belt conveyor 1 is driven
forward to bring new pocket blanks into position on the lifting bar
3. When the pocket blank comes into position, it covers the lamp 9
and prevents light from reaching the photocell 8 and the belt
conveyor stops.
Referring specifically to FIG. 12B, the photocell 8 is connected
into a control circuit 500 which is used to turn on and off a
conveyor drive motor 516 (See FIG. 12H). A pair of transistors 502
and 504 are connected together to form a conventional Schmitt
trigger circuit, with the photocell 8 connected to the input of the
trigger circuit. The output of the trigger circuit is fed
successively to two amplification stages, one including transistor
506 and the other including transistor 508. The output signal from
transistor 508 is conducted over an output lead 510 to the coil 512
of a "STACK FEEDER" relay 513 (FIG. 12E) which operates contacts
514. The contact arm for contacts 514 is shown in the drawing in
its normal position in which it connects an indicator lamp 518
between a voltage source marked "H" and ground so as to light the
indicator lamp.
Initially, before light reaches photocell 8, the transistor 502 is
off, transistors 504 and 506 are on, whereas transistor 508 is off.
When light from the lamp 9 reaches the photocell 8, its resistance
drops from a very high value to a very low value, with the result
that the base lead of transistor 502 is connected essentially to
ground, and a negative-going output pulse is delivered to
transistor 506 to turn it off. When transistor 506 is turned off,
voltage is applied to the base lead of transistor 508 to turn it
on, and a signal is sent over lead 510 to relay 513 to actuate the
contacts 514 and turn on the motor 516 and turn off the indicator
lamp 518.
When light ceases to strike the photocell 8, in response to the
movement of pocket blanks into proper position, thus covering the
lamp 9, the transistor 502 is off, transistors 504, 506 turn on
again and transistor 508 turns off, the motor 516 stops, thus
stopping the belt conveyor 1, and the indicator lamp 518 lights
again.
By means of the foregoing circuit, a stack of pocket blanks is
maintained in proper feeding position automatically.
POCKET PICKUP AND TRANSFER DEVICE CONTROL CIRCUIT
The relay contacts are shown in the drawings in the positions they
take when the transfer arm 6 (See FIG. 2) is in its furthest
clockwise position and is holding a pocket blank over the conveyor
rollers 10 which are ready to convey the blanks to the sewing
machine. When the circuit is in this condition, capacitor 522 (FIG.
12E) is connected to the common positive 26-volt DC supply and thus
is fully charged to that voltage. When a "START" switch is pressed,
capacitor 522 suddenly is connected to the coil 524 of a "PULLER"
relay 523 (FIG. 12D). This creates a current pulse through coil 524
and causes the relay contacts operated by that coil to switch. One
such set of contacts 525 (FIG. 12G) closes and thus actuates a
solenoid-operated pneumatic valve 526. Valve 526 actuates a
pneumatic cylinder 50 (FIG. 3). Cylinder 50 is spring-biased
towards its upper-most position. Operation of the solenoid valve
526 drives cylinder 50 downwardly against the conveyor roll 10a, as
has been explained above. This performs the "pulling" function of
the machine in which the pocket blank is pulled loose from the
transport mechanism and is freed to be carried by the conveyor
rolls 10 to the sewing machine.
Operation of the puller relay 523 closes its contacts 528 (FIG.
12D) which energize the coil 534 of another relay 535. Because of
the transient nature of the current flowing through the puller
relay coil 524 from the capacitor 522, it quickly becomes
deenergized. However, relay 535 remains energized because it has a
set of "holding" contacts 536. The pickup and transfer device drive
motor 39 (FIG. 12G) is started when contacts 540 of relay 535 are
actuated.
Drive motor 39 (See FIG. 12G) is a two-winding reversible AC motor.
When terminal 541 is grounded, the motor rotates in a
counterclockwise direction, and when terminal 543 is grounded, the
motor 39 rotates in a clockwise direction. When the transfer
mechanism is in its furthest clockwise position, clockwise
microswitch 42 is open and counterclockwise microswitch 40 is
closed. When contacts 540 of relay 535 are actuated, terminal 541
of motor 39 is grounded and the motor rotates in a counterclockwise
direction until it has traveled approximately 90.degree., at which
point a cam attached to the shaft of the motor 39 opens microswitch
40 so that the motor 39 stops.
Actuation of the counterclockwise microswitch 40 connects one end
of the capacitor 545 to ground. The other end of capacitor 545 is
connected to a positive 150 volt source through coil 546 of another
relay 544 (FIG. 12F). This, of course, actuates relay 544 and opens
its contacts 548. This removes the energization of coil 534 of
relay 535, and causes all of the contacts of relay 535 to return to
their initial condition. The pickup and transfer mechanism now is
in its furthest counterclockwise position and is ready to pick up a
new pocket blank.
When relay 535 was actuated, a capacitor 539 (FIG. 12D) was
connected through a resistor 537 to a 150 volt source, and thus
became charged. When relay 535 is deenergized, the charged
capacitor 539 becomes connected to a coil 552 of a relay 550 (FIG.
12F). Capacitor 545 discharges its stored energy through the coil
552 and operates contacts 553 to energize the solenoid of a
solenoid-actuated lifting bar valve 554. When the transient current
from capacitor 545 decreases, after a short time, to a value below
the holding current value of relay 550, the contacts 553 reopen.
The lifting bar valve 554 actuates vertically-driven hydraulic
cylinders 44 (See FIG. 4) to lift several layers of pocket blanks
up against the adhesive tape 7 so as to cause the uppermost pocket
to adhere to the tape. When the valve 554 becomes deenergized, the
remaining pocket blanks drop back to the original position when the
cylinders 44 move back to their original position. The entire
lifting cycle takes place within about 0.1 second.
It should be evident that the timing sequence of the foregoing
operation is controlled by the capacitance values selected for the
capacitors 539 and 545.
Next, with relay 544 (FIG. 12F) deenergized, contacts 548 of that
relay connects terminal 543 of the drive motor 39 (FIG. 12G) to
ground through contact 542 of the puller relay 523, contact 540 of
relay 535, and the clockwise microswitch 42 which now is closed.
This causes the motor 39 to rotate in a clockwise direction and
moves the pocket which is stuck to the tape 7 through a 90.degree.
angle to a position overlying the conveyor rollers 10. At this
point the clockwise microswitch 42 opens, the motor 39 becomes
deenergized, and the pocket pickup and transfer mechanism is ready
for another cycle of operation.
It should be noted that capacitor 545 (FIG. 12D) remains charged
after the motor 39 stops. However, when the puller relay 523 is
actuated at the start of the next cycle of operation, contact 530
connects capacitor 545 in series with a resistor 547 to dissipate
the charge on capacitor 545 and prepare it for operation in the
manner described above.
SEWING CONTROL CIRCUIT
I. Sewing the First Edge
As the pocket blank travels along on the conveyor rollers 10, its
leading edge comes into the path of the light beam extending from
lamp 19a (See FIG. 7) to the "inch" photocell 19. This operates a
control circuit 560 (See FIG. 12a) in the following manner: The
photocell 19 is connected in a circuit 560 in combination with
transistors 561, 563, 593 and 595 in a manner substantially
identical to the manner in which photocell 8 in circuit 500 (FIG.
12B) is connected to transistors 502, 504, 506 and 508. The result
is that the covering of the photocell 19 creates an output signal
on lead 577 which is connected to the coil 564 (FIG. 12D) of an
"INCH" relay 562. This energizes relay 562 and moves the contact
arm for contacts 572 to its lower position in which it connects to
ground the coil 584 of another relay 582 (See FIG. 12F). The other
terminal of coil 584 is connected to the common positive 26 volts
DC supply through a switch 580 (See FIG. 12E) which is a part of a
"SEW" relay 576 which is, at this time, deenergized. Thus, relay
582 is energized and relay contacts 588 (FIG. 121) are actuated to
energize a corner lifter valve 590. Actuation of the corner lifter
valve 590 actuates a pneumatic corner lifter cylinder 231 (See FIG.
1) which lifts left-hand trailing edge of the pocket which
previously was sewn so to prevent interference with the new pocket
blank which is being sewn.
The new pocket then moves on and covers the optical path between
the light source 20a (See FIG. 7) and the "sew" photocell 20. The
photocell 20 is connected into a photocell amplifier circuit 592
(See FIG. 12C) which is substantially the same as circuit 500 shown
in FIG. 12B except that it has one less stage of amplification.
When the last transistor 593a turns on, output lead 594 is
grounded, thus energizing the coil 598 of a second "sew" relay 596
(FIG. 12D). This actuates contacts 608 (See FIG. 12G) and has the
effect of energizing the coil 612 of another relay 610 (See FIG.
12E). Referring next to FIG. 12H, the foregoing has the effect of
connecting the coil 612 to the power supply through contacts 575 of
the relay 562 and contacts 567 of another relay 568 (FIG. 12E). The
energization of relay 596 also causes the presser foot and guider
to drop down onto the pocket. The dropping of the presser foot
actuates a microswitch 614 (See FIG. 12G) to move its arm to the
rightmost position to connect one terminal of a clutch valve 615
(FIG. 12H) and the coil 612 of relay 610 (FIG. 12E) to ground. This
actuates the clutch and starts the sewing machine.
The second "sew" relay 576 (FIG. 12E) is energized at the same time
the first "sew" relay 596 (FIG. 12D) is energized because the coil
578 of relay 576 is connected to the same energization lead 594 as
is the coil 598 of relay 596. INCH relay 562 is energized a short
time prior to the energization of the SEW relays. When the
energization of relay 576 causes the switching of contacts 581,
this connects a charged capacitor 639 (FIG. 12D) through relay
contacts 574 to the coil 636 of a relay 634 (FIG. 12F). Contacts
638 of relay 634 (FIG. 12I) are momentarily actuated to deenergize
a side guider valve 640 which briefly brings the side guider down
upon the pocket momentarily to aid in guiding in its movement.
Considering once again the movement of the pocket blank during the
stitching of its first side, as the pocket blank moves far enough
to uncover the photocell 19 so that light reaches it from lamp 19a
(FIG. 7) the resistance of the photocell 19 drops to a low value,
transistor 561 turns on, transistors 563 and 593 turn off, and
transistor 597 also turns off after a time delay sufficient to
allow the capacitor 583 to discharge to a value lower than the
Zener breakdown voltage of a Zener diode connected in series with
the base lead of transistor 597. The time delay for transistor 597
to be turned off can be adjusted by means of potentiometer 584
which is connected in parallel with capacitor 583.
At this time, the first seam of the pocket has been sewn to within
approximately one-half inch of the pocket bottom, when transistor
597 turns off, relay 562 (FIG. 12D) is deenergized. This causes a
shift in the sewing speed of the sewing machine to a slow speed so
that the pocket blank can be stopped accurately to make the turn to
sew the next seam. Deenergizing relay 562 deenergizes the clutch
valve 615 and therefore deenergizes the clutch. This also energizes
the brake valve 569 (FIG. 12H) and transistor 595 through contacts
575 of relay 562 (FIG. 12G) and contacts 567 of relay 568 (FIG.
12H). This rapidly slows down the sewing machine. The
deenergization of relay 562 energizes the coil 652 of relay 650
(FIG. 12F). The energization of relay 650 (FIG. 12F) closes
contacts 654 and energizes the coil 624 of another relay 622 (FIG.
12F) which closes contacts 627 (FIG. 12I) which in turn energize a
small auxiliary sewing machine motor 629 (FIG. 12I) which drives
the sewing machine at a slow speed. Motor 629 preferably is a
series-wound DC motor which produces a low speed which is termed an
"inching" speed herein.
After the sewing machine makes two or three revolutions at inching
speed, the pocket has moved far enough to uncover the photocell 20
and deenergize the two sew relays 596 and 576. When relay 596 is
deenergized, a synchronizer cam 656 (FIG. 12D) becomes in control
of relay 650. The synchronizer cam 656 is attached to the main
shaft of the sewing machine and has two brush contacts 657 and 658,
as shown in FIG. 12D. The cam 656 has a cutout portion of a lesser
radius than the remainder of the wheel. The wheel is made of a
conductive material. When the sewing machine rotates to positions
such that contact 657 is in the gap, the needle is down, relay 650
is deenergized, and the auxiliary motor 629 and the sewing machine
stop. Note that when contacts 655 (FIG. 12I) of relay 650 are
actuated, they place a short circuit across the armature of motor
629 while a field winding of the motor still is being energized.
This provides dynamic braking of the motor and stops it very
rapidly. Relay 622 remains energized for short time after relay 650
is deenergized because of the charge stored on capacitor 631 (FIG.
12F).
After a short time, relay 622 deenergizes, the presser and guider
valve 620 (FIG. 12I) operates to lift the presser foot and guider.
The lifting of the presser foot causes the microswitch 614 (FIG.
12G) to move to its leftmost position. This grounds the coil to 662
of a "TURNER" relay 660, and permits a charged capacitor 664 (FIG.
12E) to discharge through coil 662 and actuate the relay. Contacts
666 (FIG. 12G) of relay 660 are operated to ground one terminal of
the solenoid of a "TURNER VALVE" 668 which actuates the pocket
turner cylinder which rotates the pocket 90.degree. and prepares it
for the sewing of the next seam.
During the rotation of the pocket, the coil 672 of a relay 670
(FIG. 12D) is energized through the contacts 674 of relay 660, and
the relay 670 is latched in an energized condition by one of its
own sets of contacts 676. The turning pocket covers first the sew
photocell 20, thus again actuating relays 596 and 576, and then the
pocket covers the inch photocell 19, this energizing relay 562.
This action deenergizes the presser and guider valve 620 (FIG.
12I), allowing the presser foot to drop and move microswitch 614
(FIG. 12G) to the left position. This energizes the clutch valve
615 (FIG. 12H) to start the sewing machine in sewing the second
pocket.
II. Sewing the Second and Third Edges
The operation of the machine in sewing the second seam and
negotiating the second turn is substantially the same as with the
first seam and first turn, with several exceptions. First, the
contacts 673 of relay 670 connect inching time control
potentiometer 582 in the inching circuit 560 and in place of
potentiometer 584, in order to permit optimizing the timing of the
circuit functions. Also, when relay 660 is actuated at the second
turn, its contacts 663 connect the coil 680 of a "SEW OFF" relay
678 (FIG. 12D) to a capacitor 677 through contacts 679 of relay
670. The capacitor 677 has a charge which was stored during the
turning of the pocket at the first corner. This charge is
discharged through coil 680 to operate relay 678, and the contacts
682 latch the relay 678 in an energized condition.
The operation of relay 678 performs several functions; the
switching of contacts 681 prevents the turner cylinder from turning
the pocket at the end of the third seam, and energizes relay 628
(FIG. 12F), whose contacts 691 ground the capacitor 664 (FIG. 12E)
and discharge it, thus preventing the operation of the turner relay
660 the next time the presser foot microswitch 614 is operated.
Also, a new time delay potentiometer 686 (FIG. 12D) is connected in
series with the usual time delay potentiometer by means of contacts
685. This permits a longer time delay at the end of the third seam
in order to permit the sewing of a thread "chain" between adjacent
pockets. Further, the pocket pickup and transfer unit traverses
another cycle when contacts 683 of relay 678 connect capacitor 522
(FIG. 12E) to the coil of the puller relay 523. Thus, a new pocket
blank is fed into the sewing machine as the old pocket is being
finished.
Hence, a situation exists in which the old pocket still is covering
the sew photocell 20, and the new pocket has just covered the inch
photocell 19. The inch timing circuit is in the middle of its
timing function and the new pocket covering the inch photocell
would reset this timing circuit and the machine would continue to
sew instead of sewing a thread chain of approximately one half inch
and then stopping. An inhibit circuit is employed to prevent the
undesired action. When relay 678 energized, its contacts 681
energized relay 628 (FIG. 12F and supplied a base drive to turn on
transistor 574 (FIG. 12A). Note that the collector circuit of
transistor 574 is connected to the inch photocell 19. The pocket
was at the start of the second turn when relay 678 energized.
Capacitor 690 (FIG. 12A) which charges slowly enough not to reach
the breakdown voltage of Zener diode 692 before the pocket, in
turning, covers the inch photocell 19 which turns off transistor
561, and turns on transistors 563, 593, 595 and 573 and prevents
transistor 574 from turning on due to loss of its base drive. As
the pocket is being sewn from the second turn and uncovers the inch
photocell 19, transistor 561 turns on, and transistor 563, 593, 595
and 573 turn off, which now permits base drive and turns transistor
574 on. Since transistor 574 is shunted across the inch photocell,
the circuit will be locked in this mode of operation and a new
pocket covering the inch photocell has no effect as the circuit
continues to function as if the inch photocell were not being
covered until the sewing machine has formed the chain thread, and
relay 678 has been reset by the opening of contacts 580 of relay
576 (FIGS. 12B). This causes relay 628 (FIG. 12F) to deenergize
after a short delay due to capacitor 693. The deenergization of
relay 628 turns off transistor 574 and returns the inch circuit 560
back to its normal operation.
D. THREAD BREAKER CONTROL CIRCUIT
As a completed pocket travels down the output conveyor with the
thread chain still linking it to the next pocket, the completed
pocket covers thread breaker photocell 56 (FIG. 12B) which is
connected in a photocell amplifier circuit 706 like the circuit 592
shown in FIG. 12C. Circuit 706 produces an output pulse over a lead
704 which is conducted to the coil 702 of "BREAKER" relay 700 (FIG.
12E) to energize relay 700. Contacts 710 of relay 700 connect a
charged capacitor 712 to a relay 714 (FIG. 12F) which is
momentarily energized and in turn energizes a pneumatic value 720
(FIG. 12I) through contacts 718. The valve 720 forces the thread
breaker wheel 24 down onto the completed pocket and forces it
against the breaker roller 10c. Since the speed of roller 10c is
substantially greater than that of the other rollers, this action
breaks the thread chain joining the pockets.
E. STACKING CONTROL CIRCUIT
The completed packet moves along and then covers the stacker
photocell 25 (FIG. 12C), which is connected into a photocell
amplifier circuit 722. The first portion of circuit 722, including
transistors 724, 726 and 728, produces an output signal over lead
732 which energizes the coil 736 of a "STACKER" relay 734 (FIG.
12E). Relay 734, through contacts 740, operates a four-way stacker
valve 742 (FIG. 12H), which cause operation of the stacker
mechanism to flip the completed pocket through an angle of 180
.degree. onto the platform 32. The contacts 738 supply additional
base drive for transistor to keep it turned on 728 during the
period when the completed pocket is being transported to the
platform 32 and the photocell is uncovered. Switching of the
contacts 740 allows capacitor 744 (FIG. 12C) to start charging.
When its voltage reaches the breakdown voltage of a Zener diode
746, a transistor 730 turns on and short-circuits the base lead of
transistor 728 to ground, turns off relay 734 and valve 742, which
returns the stacking mechanism to its original condition, ready for
the next pocket. The potentiometer 748 controls the charging rate
of capacitor 744 and thus controls the timing of the stacking
mechanism.
When contacts 739 are switched by actuation of relay 734, capacitor
758 (FIG. 12B) is allowed to start charging. When it has charged to
the breakdown voltage of Zener diode 760, a transistor 756 turns on
and actuates a "STACK LEVELLER" relay 750 (FIG. 12E). This
energizes the stack leveler motor 755 which drives the stack of
completed pockets down for a short time until relay 734 turns off,
thus lowering the stack to keep it level as each pocket is added to
the stack.
F. BOBBIN CHANGE CONTROL CIRCUIT
The machine has a monitor and alarm system which makes it
relatively easy for one operator to operate several machines. A
lockstitch sewing machine using a bobbin is used, and before the
thread on the bobbin is used up, the machine will sound an audible
alarm and will turn on a light indicating that it is time for a
bobbin change. After the sewing machine furnishes the pocket at
which time the alarm sounded, the automatic pocket feed mechanism
is disabled and the machine will not sew another pocket until it is
attended to by the operator. Relay 634 (FIG. 12F) operates at the
start of each pocket cycle, and its contacts 638 actuate the clutch
761 (FIG. 12I) of an electric counter (not shown). After a
predetermined number of pockets has been sewn, the counter causes a
microswitch 762 (FIG. 12D) to open, thus removing ground from relay
523 and preventing the feeding of pocket blanks. Microswitch 762
(FIG. 12D) has two sections. The second section 768 (FIG. 12F) is
closed by the counter. This operates "CHANGE BOBBIN" relay 764 and
lights a lamp 770 to signal the need for a bobbin change. A warning
buzzer 774 and a 25 watt light bulb 776 are energized by contacts
772 of relay 764. When the operator presses the reset button to
reset the counter, the counter circuits are connected so as to turn
off the buzzer and signal lamps.
G. SEWING MALFUNCTION CONTROL CIRCUIT
The machine of the present invention includes devices for detecting
and signalling the malfunction of the machine.
One such malfunction is breakage of the top thread in the sewing
machine. Such breakage is detected by a switch 782 (FIG. 12E) which
closes when the thread breaks and removes the ground connection
(through contacts 784 of relay 610) to the base lead of the first
transistor 788 in an amplifier circuit 785 (FIG. 12C) which
supplies energization current to the coil 780 of a
normally-energized "SEW DETECTOR" relay 778 (FIG. 12E) through an
output lead 792. The foregoing deenergizes relay 778 and
deenergizes another normally energized relay 796 (FIG. 12E). This
causes contacts 800 to open, deenergizing relay 562 (FIG. 12D) and
causing the sewing machine to brake to a stop. Also, a buzzer is
actuated by the deenergization of relay 796.
The thread breakage detector circuit is not operative when the
sewing machine is running at "inching" speed because, at that time,
the +26 volt supply to the relay coil 798 is removed by the opening
of contacts 654 of relay 650 (FIG. 12F).
It is possible that the sewing machine can run off of the side of
the pocket due to some malfunction causing the "inch" and "sew"
photocells 19 and 20 to be covered. If this happens the sewing
machine will run continuously while not sewing material. Since this
results in rapid wear on the sewing machine presser foot and feed
dogs, a circuit is employed to stop the sewing machine if this
malfunction occurs. If relay 596 (FIG. 12D) is energized for a
longer time than it normally takes to sew a pocket side, the
malfunction just described has occurred. When relay 596 energizes,
contacts 600 open, turning transistor 804 (FIG. 12B) off, thus
permitting a capacitor 806 to charge. If relay 596 stays energized
too long, a transistor 808 will be turned on and will energize the
"SEW TOO LONG" relay 568 (FIG. 12E). This energizes the brake valve
569 which stops the machine. This also prevents the machine from
"inching," and operates a buzzer, and turns on a lamp 810.
Another malfunction which is detected is a pocket jam in the output
conveyor. Relay 582 (FIG. 12F) energizes as a pocket is moving into
the sewing machine. If pocket flow is normal, the pocket which has
just been sewn will be transferred to the end of the output
conveyor and will actuate the stacker photocell and will energize
the stacker relay 734. If the time delay between energizing relays
582 and 734 is longer than normal, the pocket has jammed somewhere
on the output conveyor. The contacts 586 of relay 582 energize a
relay 812. The opening of contacts 816 permits a capacitor 818
(FIG. 12B) to charge. In normal operation, the opening of the
contacts 822 of stacker relay 734 causes relay 812 to deenergize
and capacitor 818 to be shorted to ground. If relay 734 did not
operate (due to the pocket jamming before reaching the stacker)
capacitor 818 will continue to charge and eventually will provide
base drive current for transistor 820, thus energizing relay 824
(FIG. 12D). Relay 824 operates a buzzer and turns on the signal
lamp 826. A potentiometer 828 (FIG. 12B) provides means for
adjusting the time delay before transistor 820 turns on.
As can be seen from the above discussion and drawings, the present
apparatus for advancing, conveying, positioning, and removing
workpieces from the sewing machine is designed to operate without
confining the workpieces in mechanical patterns or constraining
devices, save for those actually used during the sewing cycle. This
approach has allowed the operation with misaligned workpieces
because the novel apparatus has been conceived to effect the
alignment of a freely flowing workpiece during its movement from
station to station by novel guidance means operating in combination
with each other. This practical approach has saved numerous
mechanical interlinkages and elements in the place thereof relying
on the properly designed guide elements and control circuits.
Moreover, the pocket blanks may be sewn either face up or face down
and with or without facing in either of these positions as the
apparatus accommodates the variations in thickness, width, hand,
drape, and other characteristics of the material being sewn,
essentially without requiring any machine modifications or
far-reaching adjustments.
Whereas normally a skilled operator is required at each machine
turning out the described pocket blanks, now an untrained operator
or one with little training may operate a number of these machines
simultaneously. The automatic sewing operation is especially
desirable, as the product obtained is a result of a more consistent
and precise sewing operation despite the curved stitching path and
the pivoting turns and continued stitching at the two corners of
the blank. Also, it is especially noteworthy that with the
advancing and removing of each individual workpiece, the
distraction element associated with manual operation is eliminated
thereby minimizing the statistical incidence of accidents.
* * * * *