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.

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.

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.