US3747919A - Adjustable work pick-up device - Google Patents

Abstract

A device for picking up and transferring single plies of sheet material, especially a wide variety of fabric and the like which may be in a stack, comprising a presser foot, a relatively movable work-pinching member cooperative with the presser foot, and means for adjusting the nip of the member and the foot. Threaded means adjustably limits the extent of initial separation of the pinching member and the foot whereby appropriate nipping of different thicknesses and types of material is obtained.

Description

United States Patent [191 Stewart et al.

ADJUSTABLE WORK PICK-UP DEVICE Inventors: James B. Stewart; Carlton G. Lutts,

both of Salem, Mass.

Assignee: USM Corporation, Flemington, NJ.

Filed: June 6, 1972 App]. No.: 260,304

US. Cl. 271/19, 271/18 Int. Cl. B65h 3/12 Field of Search 271/18, I9, 20, 21,

References Cited UNITED STATES PATENTS 5/1966 Southwell et al. 27l/l9 11/1967 Smith et al 271/25 X Aliv- July 24, 1973 3,588,091 6/l97l Stone et al 271/19 Primary Examiner-Even C. Blunk Assistant Examiner-Bruce l-l. Stoner, Jr. Attorney-Carl E. Johnson et al.

nipping of different thicknesses and types of material is obtained.

2 Claims, 6 Drawing Figures PAIENIEU JUL 2 4:915

I Mu ADJUSTABLE WORK PICK-UP DEVICE CROSS REFERENCE TO RELATED APPLICATION Concurrently herewith another application, Ser. No. 260,306 filed June 6, 1972, is being filed with Mr. Carlton Lutts and Mr. James Stewart as joint inventors and pertaining to the ply separation means illustrated in the present application. A further concurrent application, Ser. No. 260,305 filed June 6, 1972 filed in the name of R. R. Walton et a1. relates to the pick-up construction shown herein.

BACKGROUND OF THE INVENTION A need exists for a versatile pick-up device capable of automatically moving successive individual plies of fabric and the like from an external portion, for instance the top, of a stack and preferably without disturbing the position of an adjacent or underlying ply in the stack. The problem is difficult of solution in reliable manner, and often because there may exist a cleavage of fibers in the interface region. Suction has frequently been employed in combination with other elements such as card cloth or bristles for penetrating work pieces. When they are pervious to air flow the underlying ply is or may be disturbed, and excessive penetration of the work by the pointed means can have a like effect. Need for a precision mechanism for controlling movement of the pointed elements and their initial separation from a cooperative ply-nipping member is recognized in the copending Walton application above cited.

SUMMARY OF THE INVENTION In view of the foregoing it is a main object of this invention to provide, for use in a work transferring machine, a pick-up device of cooperating jaw type construction, and jaw adjusting mechanism enabling the jaws to be effective on a range of flaccid sheet material for mechanically seizing and lifting a locality of an external ply of a stack of flexible work pieces without affecting an underply.

Another object of the invention is to provide jaw actuating mechanism including easily adjustable means controlling the degree of jaw separation whereby a localized portion of the exposed sheet of a stack of limp plies can enter between the jaws and be seized and folded on itself during lift-off and transfer.

In accordance with these objects, a feature of the invention resides in the provision, in combination with mounting means for a pickup dvice device a presser foot for bulging or puckering an exposed locality of a ply, and a pivotal pawl yieldingly cooperative with said foot for clamping a portion of the puckered locality upon the jaw surface, of a pinch adjusting nut threaded on the mounting means and having camming engagement with the pawl to control its spacing from the presser foot.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features of the invention will now be more particularly described in connection with an illustrative fabric pick-up device and with reference to the accompanying drawings thereof, in which:

FIG. 1 is a view in side elevation of a pick-up and ply separating assembly in initial work engaging condition;

FIG. 2 is a bottom view of the pick-up portion,

FIG. 3 is an axial section showing a pincer of the pick-up device with its adjustable nip controlling means in work seizing position over a stack;

FIG. 4 is a view similar to FIG. 1 but showing the pick-up rotated by its ply separating mechanism;

FIG. 5 is a transverse section taken on the line V-V of FIG. 3 indicating nut means for adjustably limiting the stroke of the pincer, and

FIG. 6 is a detail view of an adjustable detent for controlling friction.

DESCRIPTION OF PREFERRED EMBODIMENT A machine of the general type for automatically feeding fabric sheets W or the like from the top of a stack S is illustrated and described in U. S. Letters Patent No. 3,531,103 issued Sept 29, 1970, in the name of R. R. Walton. The particular pick-off devices therein rely on suction as does the adjustable pick-off means disclosed, for instance, in U. S. Letters Patent No. 3,550,932 issued Dec. 29, 1970 in the name of R. C. Mason. The present invention provides an adjustable mechanical pick-up device generally designated 10 (FIGS. 1, 3) which is herein illustrated as employed in a fabric transfer machine (not shown) in combination with a fluid pressure operated ply separating mechanism generally designated 14, the assemblage 10, 14 (FIG. 4) being shown by way of example only as adjustably mounted on a movable carrier 16 (FIG. 1) of the machine as, for instance, in the manner disclosed in the cited Mason Patent. It will be understood that, according to the size, shape, and weight of the work pieces W to be transferred, one or a plurality of the assemblages 10, 14 may be mounted in any selected pattern on the carrier 16 as needed.

The pick-up device 10 herein claimed may be operated in combination with other ply separating mechanism, and the ply separating mechanism 14 claimed in the cited concurrently filed Lutts et a1 application may be operated in combination with other pick-up devices. It will be understood the plies W to be transferred may be top, bottom or otherwise externally exposed with respect to a stack.

For detachably and slidably supporting the assemblage l0, 14 a tubular body 18 FIG. 1) has a threaded stem at its upper end extending through a slot in the carrier 16 for receiving a thumb nut 20. The body 18 is formed with ports 22, 24 (FIG. 1) and a partly helical slot 26 for purposes later explained. Slidable axially in the body 18 is a piston 28 having a radial hole the wall of which is threaded for receiving a cam pin 32 slidably extending through the slot 26. As shown in FIG. 1 the upper portion of the slot 26 is longitudinal and the lower portion extends helically at about 45, relative heightwise and turning movement of the piston 28 being thus limited. A head 34 of the piston is disposed at the lower end of an upper chamber 36 in the body 18 having communication with the port 22, and a lower chamber 38 in the piston communicates with the port 24 via a hole 40 in the wall of the piston 28 when the latter is in its relatively lower position, the hole 40 being effectively closed by the wall of the body 18 when the piston 28 is relatively raised as shown in FIG. 4.

Within the lower end of the piston 28, a cylindrical stem of a presser foot 42 is axially slidable within limits, being secured by a set screw 44 (FIG. 1) extending through a longitudinal slot 46 in the piston and threaded into the stem. As shown in FIGS. l-3, a work engageable peripheral portion 48 of the presser foot is eccentrically enlarged and circular, and centralized with respect to a diameteric slot 50. Secured in this slot by a set screw 52 is a V-shaped tooth 54 having its bevelled faces 56, 56 receding in the slot and extending upwardly to define a shelf portion 58 having an apex slightly above the work engaging surface 48. For cooperating with the presser foot 42 the pick-up device 10 includes a pinch pawl 60. The pawl 60 has pin 62 and slot 64 connection in a heightwise kerf in the presser foot 42, the arrangement being such that a pair of parallel rows of pointed and biased teeth 66 arcuately disposed on the underside of the pawl 60 are respectively movable in their planes to engage the top sheet W in the locality P (FIGS. 1, 3) where it may have been bulged or puckered by the compressive action of the presser foot portion 48 and, by means next explained, gather the localized portion in pinching relation onto the shelf portion 58, as shown in FIG. 3.

Adjustably threaded onto the lower end of the piston 28 is a pinch adjusting ring nut 70 (FIGS. 1, 3) having internally a circular camming lip 72 (FIG. 3). A leaf spring 74 is secured at one end to the pawl 60 and has a free downwardly extending portion engageable with an innerface 76 of the presser foot 42 to urge the pawl toward its open or inoperative position. The spring 74 accordingly yieldingly resists movement of the teeth 66 toward pinching relation with the presser foot 42, and more positive pinching is effected as the lip 72 is relatively lowered by the piston to cam the pawl 66 toward the shelf portion 58 by mechanism later explained. The ring nut 70 at 90 spacings is semi-bored as at 76 (FIG. both radially and longitudinal to provide four alternative positions for mating with a cut-away portion 77 in the piston 28 and thus accommodating a pinch control lock pin 78. It will be understood that the pin 78 is detachable and insertable to lock the ring nut in the particular 90 rotational setting affording best results for the heightwise position of the lip 72, a relatively higher lip generally permitting a wider initial nipping position for pinching thicker or more substantial work pieces. Viewed alternatively, for dealing with very thin sheet material, refined adjustment by means of the ring nut 70 insures that only a single ply will be seized.

Preferably, the degree of friction between the presser foot stem and the piston 28 is adjustably controlled better to accommodate different types of work pieces W and insure that the top piece will be suitably puckered about the shelf portion 58, for instance as illustrated at P (FIGS. 1 and 3). To this end, and as herein shown in FIG. 6, for instance, a spring-pressed ball detent 80 engaging the interior wall of the piston 28 is nested in the presser foot stem and backed by an adjustable set screw 82. It will be understood that threading the screw 82 inwardly to increase friction will cause the presser foot 42 to react harder on the stack S before relatively yielding upwardly.

In operation of the fabric transferring machine relative movement of approach of the stack S and the pickup device is in this case effected by raising the stack by a cyclical elevator mechanism 83 (FIG. 1) until a penumatic sensor in the form ofa tube 84 (FIGS. 1 and 3) signals for stack lowering (following a time delay) after the top ply has been initially engaged as shown in FIG. 1. The chamber 38 is then open to exhaust, and

a low pressure (roughly on the average of about pounds per square inch) provided in the chamber 36 is then only adequate to nearly counterbalance a tension spring 86 interconnecting the carrier 16 and the pin 32. As shown in FIG. 1 the sensor tube 84 is slidably mounted in a vertical guide sleeve 88 fixed in a collar 90 secured on the piston 28. The tube 84 is disposed to be blocked at its lower end by the presser foot 42 approaching an upper limit as shown in FIG. 3. Air flow downwardly in a flexible supply line 92 connected to the tube 84 is thus stopped and the resultant signal, in addition to stopping elevation of the stack S, also signals for operation of the ply separating mechanism 14 by dumping pressure from the chamber 36 whereupon the spring 86 at once causes lifting and rotation of the piston 28 and likewise of the presser foot 42 for effecting separation of the picked-up top ply. The upward displacement of the sensor tube 84 is against resistance of a return spring 94.

Reverting to a more detailed consideration of operation of the pick-up device 10, which functions prior to rotation about a vertical axis, as the stack S is elevated the presser foot 42 yields upwardly with resistance as suitably selected to compress and thereby bulge or pucker a locality of the top ply W as at P eccentrically of the piston 28 thus causing an irreguar and somewhat annular wave in the top sheet immediately beneath the open pincer teeth 66 to come into engagement therewith at each side of the apex of the shelf 58. The pawl 60, as the presser foot is relatively raise in the piston 28, is cammed by the lip 72 to pinch the puckered portion upon the shelf 58. In this action the rows of teeth 66 first urge the workagainst the V-tooth point and then rise further as allowed by the slot 64 to move past that point on its opposite sides to hold a small work portion folded and clamped upon itself. Only the single top ply is thus pinched.

Upon actuation by the spring 86 as aforesaid, the piston 28 is raised following pick-up and, by means of the cam pin 32 of the ply separating mechanism 14, rotaeed rotated as viewed from above and shown in FIG. 4. Thus at one or more selected localities the seized work is subjected to localized twisting to disrupt cleavage of interfacial fibers. It will be understood that certain pairs of the assemblies 10-14 may provide twisting in opposite direction, their slots 26 in such cases being oppositely inclined helically in order to provide desired stress patterns such as suggested in FIGS. 2 and 3 considered most effective for insuring that an underply is not disturbed as the top ply alone is separated and relatively raised.

The assemblies 10-14 are now jointly moved by the carrier 16 to laterally position the work over a selected delivery position. At the end of this lateral feeding stroke a switch (not shown) is actuated to pressurize the upper chamber 36 to a degree considerably higher than previously. This forces the piston 28 downward against influence of the spring 86 to return the cam pin 32 to the bottom of its slot 26. The downward movement of the piston and its resultant rotation to unstress the ply then being carried open the port 40 to let air under pressure through the port 24 and into the chamber 38. As a consequence the presser foot 42 is abruptly forced downwardly to enable the pawl 60 to be freed by inertia and thus causes the supported top ply to be released for delivery.

In the course of the return trip of the carrier 16 from the work delivery position to the pick-up position above the stack for repeating the cycle, the chamber 38 is exhausted and the chamber 36 is again provided with its lower pressure.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. A pick-up device for transferring single plies of flexible fabric or the like from a stack, comprising a presser foot, a mounting means yieldingly holding the presser foot for relative movement toward and from a surface of the stack, a work engaging pincer pawl movably supported by the presser foot for cooperation therewith, the pawl having operative connection with the presser foot and having convexly disposed workengageable teeth, spring means biasing the pawl teeth laterally away from the presser foot to allow a localized portion of an external ply of the stack to enter therebetween, and a pinch adjusting nut threaded on said mounting means and engageable with the pawl to limit lateral spacing of the pawl teeth from the presser foot, said nut being arranged during relative movement of the stack surface and the pawl to cam the pawl toward work pinching relation on the presser foot.

2. A device as in claim 1 wherein the nut has circumferentially spaced formations respectively mateable with a complemental recess in the mounting means, and a locking pin detachably receivable in the respective formations and said recess to adjustably determine the nip of the pawl.

Claims (2)

1. A pick-up device for transferring single plies of flexible fabric or the like from a stack, comprising a presser foot, a mounting means yieldingly holding the presser foot for relative movement toward and from a surface of the stack, a work engaging pincer pawl movably supported by the presser foot for cooperation therewith, the pawl having operative connection with the presser foot and having convexly disposed work-engageable teeth, spring means biasing the pawl teeth laterally away from the presser foot to allow a localized portion of an external ply of the stack to enter therebetween, and a pinch adjusting nut threaded on said mounting means and engageable with the pawl to limit lateral spacing of the pawl teeth from the presser foot, said nut being arranged during relative movement of the stack surface and the pawl to cam the pawl toward work pinching relation on the presser foot.

2. A device as in cLaim 1 wherein the nut has circumferentially spaced formations respectively mateable with a complemental recess in the mounting means, and a locking pin detachably receivable in the respective formations and said recess to adjustably determine the nip of the pawl.

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