Abstract: An attachment for a sewing machine comprises a looper bar positionable for horizontal oscillation underneath a vertically reciprocating needle, at a level determined by a workpiece feeler engaging the upper surface of a fabric being sewn, which is swingably carried on the stem of a presser foot resting on the workpiece while the latter is intermittently advanced by a bottom feeder periodically rising from a slot in a stitch plate and a reciprocable gripper foot synchronized therewith to act as a top feeder. A first sensor detects a rise in the presser foot, to an extent indicating the presence of resilient padding between an upper and a lower fabric layer, to activate the looper bar; a second sensor temporarily deactivates the first sensor whenever the bottom feeder projects above the stitch plate.

Abstract: To test the integrity of a plurality of operating circuits each including a load energizable by an associated driver under the control of a microcomputer, a capacitor charged with unipolar pulsating test voltage is connected to a common terminal of all the operating circuits and concurrently therewith to the input of a trigger element whose threshold equals about half the peak amplitude of that voltage. During one or more brief intervals the microcomputer cuts in the driver of a selected circuit and senses the output voltage of the trigger element to determine whether or not the capacitor is being discharged through that circuit. A display device controlled by the microcomputer indicates the conductive or blocked state of the selected circuit as well as a possible malfunction manifesting itself in a discharge of the capacitor before any driver is turned on.

Abstract: In an overhead-rail materials-conveyance system including an endless drive chain juxtaposed to an endless rail for driving hanger-type carriers suspended therefrom by means of wheels, a coupling assembly for carrier entrainment comprises a plurality of jaws pivotably mounted on the drive chain for swinging about respective axes parallel to the transport direction. The jaws are each provided with beveled edges for cammingly engaging coupling and uncoupling heads projecting vertically from front and back ends, respectively, of the carriers; the jaws have recesses of a breadth greater than the width of the coupling heads and less than the width of the uncoupling heads for forming locked engagements with only the coupling heads upon spreading of the jaws thereby. Upon the approach of a train of carriers towards a standing carrier, the uncoupling head thereof spreads the jaws entraining the first carrier in the train, thereby releasing this carrier.

Abstract: A sewing machine and method of operating same in which the vertically reciprocatable needle bar is mounted in a guide capable of swinging movement back and forth and the guide, in addition, is shiftable by a separate drive upon withdrawal of the needle from the fabric to form locking or anchoring stitching at the end of a stitched seam.

Abstract: A sewing machine designed to stitch together two stacked fabric layers advancing at different speeds comprises an upper and a lower conveyor belt coupled with a common drive shaft by a differential gearing. The relative speed of the two conveyor belts can be manually adjusted with the aid of a friction coupling comprising two mutually parallel larger disks with relatively offset axes and overlapping surface areas contacted by a smaller disk perpendicular thereto, the latter disk being displaceable in a common axial plane of the two larger disks to vary their transmission ratio.

Abstract: An assembly disposable at a sewing-machine station for assisting an operator in the positioning and fixing of a pair of workpieces relative to one another prior to stitching at the sewing station comprises a multiplicity of clamping modules each having six lower fingers projecting from a module housing for clamping a first workpiece to a base plate and six upper fingers for clamping a second workpiece over the first. The lower fingers and the upper fingers are rigid with respective levers pivotable by the plungers of respective pneumatic cylinders, these cylinders being energizable in a predetermined sequence by an operator-controlled push valve to effect a piecewise positioning of the first workpiece and then of the second workpiece.

Abstract: A double-lock-stitch sewing machine in which the needle-thread loop on the underside of the workpiece on a stitching plate is engaged with a gripper thread by the rotating gripper associated with the bobbin housing for the bobbin supplying the gripper thread. According to the invention, in the path of the needle-thread loop in the space between the stitch plate and the gripper, there is provided a spring wire or rod which bears upon the needle-thread loop and prevents the formation of knots or bunching in the needle thread. The spring wire is fastened to the underside of the stitch plate on opposite sides of the needle hole and flanks the latter in its undeflected state.

Abstract: A device for feeding to a sewing machine a strip of fabric, in particular a longitudinally folded band to serve as a pocket welt, comprises a generally oval-shaped guide mountable on the sewing-machine base and provided with sides shaped as U-profiles and with a tongue at an output end for folding a fabric strip upon passage thereof along a feed path to a sewing station at the machine. A beam of light from a gallium-arsenide source traverses the feed path in the region of the tongue to energize a photocell upon passage of a workpiece, the photocell being connected to a stitch counter for activating the same upon energization by the source. The guide has a length scale with graduations spaced in the direction of the feed path for implementing the manual positioning of a fabric strip prior to the feeding thereof to the sewing station, while the stitch counter is operationally coupled to the reciprocating sewing-needle drive to arrest the same upon counting a predetermined number of stitches.

Abstract: An assembly at a sewing machine for forming a piped-edge or bound pocket opening in a garment workpiece includes a pair of sewing needles for stitching two parallel seams in the workpiece and in a reinforcing strip laid thereon, a blade for cutting a slit in the fabric pieces between the two seams and a pair of cross-sectionally angular cutters removably clamped to the plunger of a pneumatic actuating cylinder and having vertices engaging opposite sides of a mandrel also mounted on the plunger. Upon charging of the cylinder, the mandrel passes through an end of the slit to widen same and consequently enable the traversing of the slit by one or the other of the angular cutters, whereby one cutter is effective to form a V-shaped incision in the fabric pieces at the slit end and the other cutter is ineffective.

Abstract: To grip the tail end of a workpiece such as a stack of fabric layers to be stitched in a sewing machine, a pneumatically actuatable clamp on a carriage reciprocably guided along a rail has an air inlet in the form of a first nipple with a lateral entrance aperture confronting a discharge opening of a stationary air-supply line when the clamp is in a retracted loading position remote from the sewing machine. Air admitted in that position to a pressure cylinder via a branch of the supply line forces the inlet duct of the clamp against a sealing ring surrounding the discharge opening to conduct the main air flow via a check valve and a control valve to an operating jack for closing the clamp, the jack including a single-acting spring-loaded piston.

Abstract: A system for the edge-parallel sewing of a workpiece, consisting of a plurality of layers, together to form a seam, e.g. in the production of trouser legs, pockets, shirts and the like, comprises a workpiece guide in the region of the needle path and formed with separators interposed between the layers, and a drag-clamping device which engages a portion of the stack of fabric layers remote from the incipient stitching operation to apply a stretching or drag force thereto. According to the invention, a retracting device is provided which, upon approach of the drag clamp to the stitching location, withdraws the guide device out of the path of the clamp.

Abstract: A sewing machine having an edge guide for producing a stitched seam along an edge of a workpiece terminating at another edge forming an angle with the first has an optical device for directing a pencil or beam of light toward a reflective surface which underlies the workpiece and is covered thereby until the movement of the workpiece exposes the reflective surface at this other edge. The optical detector then produces a signal for initiating a control function, e.g. the change of stitch pattern to tie off the end of the previously sewn seam or to lodge the needle in the fabric so that the workpiece may be turned to bring the other edge into contact with the edge guide. The control system can include a programmer for the successive stitching operations which are initiated in succession in response to the optical sensor.

Abstract: A circulating conveyor, e.g. of the type in which a load carrier passes along an endless track and supports material to be conveyed, e.g. garments suspended by hangers from the load carrier, comprises in addition to the circulating track, a load carrier which runs with a plurality of wheels on the endless rail and has a displacement chain formed by a multiplicity of rigid links each constituted by a rigid bar hinged at its ends to the adjoining links. The lateral flanks of the bar are engageable by a friction drive roller and a counter roller to displace the chain and hence the load carrier along the circulating path.

Abstract: In a monorail system in which a carriage is displaceable along a track and is adapted to be connected to or released from load carriers or the like, a coupling device is provided which comprises a hook swingably mounted on the axis of one of the supporting rollers of a carriage or carrier and adapted to engage a portion of the roller dolly of the other vehicle above the rail.

Abstract: So-called raised buttonholes are sewn on a double-lock-stitch sewing machine with the fabric workpiece turned face down on the stitchplate of the sewing machine and the upper-thread tension being such that the interlocking loops of the upper and lower threads lie upon the downwardly facing side of the workpiece. According to the invention, the upper-thread tension at the end of a buttonhole-stitching cycle for the fastening stitch is increased above the lower-thread tension temporarily so that the interlocking loops of the upper and lower threads during this last fastening stitch lie within the thickness of the material or on the upper face of the downwardly turned workpiece.

Abstract: A bobbin and gripper assembly for a double-lock-stitch sewing machine has a stitch plate lying in a horizontal plane and a gripper rotatable in a horizontal plane below the stitch plate and receiving a bobbin housing. The latter is provided with a retaining finger which cooperates with abutments formed on the underside of the stitch plate to retain the bobbin housing against rotation with the gripper. In addition, the bobbin housing is held by a spring member which is effective to yieldably retard the bobbin against rotation in the direction of rotation of the gripper by friction therewith.

Abstract: A method of and apparatus for the sewing of a succession of stitchgroups on a workpiece and for the feeding of a new workpiece into sewing position, e.g. for producing buttonholes on shirtfronts. The buttonholes are formed by linearly displacing a buttonhole stitching machine stepwise relative to a clamped edge of a fabric workpiece, and a second clamp adjacent the first is provided to retain a second workpiece in position. When the first row of buttonholes is completed upon movement of the machine in one direction, the fabric workpiece, which has been buttonholed, is released, the second fabric is engaged and brought into position, and the sewing machine is displaced in the opposite direction to form a respective row of buttonholes on the new fabric.

Abstract: A thread-cutting device for a cyclically operated double lock stitch sewing machine forming part of an automatic sewing system serves to cut the needle and bobbin or looper threads, respectively, at the underside of the throat or stitch plate of the sewing machine in close proximity to the needle hole in the throat or stitch plate. For cutting of the threads, a cutting edge is moved with respect to a stationary cutting blade into a cutting position for simultaneously cutting of the two threads. The carrier for the movable cutting tool moves the stationary cutting blade into its effective cutting position and further carries thread control fingers which assist in preparing the threads for the cutting operation. The cutting mechanism is actuated by the control means for the cyclically operated double lock stitch sewing machine.

Abstract: A fabric-transport device for a sewing machine above the stitch plate converts the rotary motion of the main upper drive shaft into reciprocating vertical motion of a pressure (hold-down) foot and a feed foot. The rotary motion is converted by a crank disc connected to a bell crank via an input crank. The bell crank swings a composite connecting rod, comprising a sliding link which interconnects the bell crank with a ternary link carrying the feet and comprising a guide bar for guiding the sliding link. The ternary link is spring-loaded against the stitch plate by a swingable arm and alternatingly lifts the pressure foot and the feed foot. The system provides for fast reduction of the velocity, towards zero velocity, of the feet as they depress to engage with the material to be sewn. SUFIELD OF THE INVENTIONThis invention relates to a feeding arrangement above the work table or stitch plate of a sewing machine for advancing or feeding of material to be sewn.

Abstract: A sewing station in which lengthy material, e.g. sleeve or trouser-leg fabric workpieces, can be provided with a seam in substantially automated operation. The material to be sewn is advanced from a loading station, where it is initially held by a fixed clamp, to the sewing machine. While the material is advanced past the sewing machine by the fabric transport, it is guided by a moving or trailing clamp which trails along with the material holding it in lightly stretched relation to the sewing machine transport mechanism. The clamps are provided with pneumatic pistons which actuate or perform the clamping functions. The pistons are controlled by switches and valves to alternatingly open and close the clamps as required by the seaming operation. The station provides for a simplified operation requiring monitoring by an operator only for the initial positioning and initial seaming.