Abstract: In a sewing machine with a feed device which comprises a feed wheel arranged next to a stitch formation point, driven synchronously with stitch formation tools, and mounted in a support provided at the housing of the sewing machine, in order to obtain an extremely exact drive in both directions, the feed wheel is placed in driving connection with a step motor. In a manner known in itself, the step motor receives stepping pulses which can be generated by a pulse generator operating synchronously with a main shaft of the machine and via a counting device that determines the feed amount. This feed amount is presettable by selectable digital data contained in a memory. In an arrangement wherein the feed wheel is connected to its drive via a deflection gearing and a transmission shaft mounted in the support, the deflection gearing consists of a ring gear attached to the feed wheel and of a pinion firmly connected to the transmission shaft.

Abstract: An apparatus for letting out skins comprises behind the parting sword a needle bar movable up and down which is movable in addition parallel to the drawoff direction of the skin through a drive mechanism. Together with a supporting plate movable up and down, the needle bar acts on the skin section already let out so that it is held taut and flat.

Abstract: At a work clamp for buttonhole sewing machines, comprising a support plate and a clamping frame arranged at a pivotable carrying lever, spaced from the clamping frame, a hold-down device with a clamping plate resiliently pressed against the work is fastened at the carrying lever. The clamping frame, when raised is pressed into a slanting position by a spring. During the descending movement of the clamping frame and hold-down device, the hold-down device precedes the clamping frame and clamps the work to the support plate. As a next step, the edge of the clamping plate of the clamping frame which is spaced from the hold-down device impinges on the work. A clamping surface of the clamping plate forms an acute angle with the support plate. As the descending movement of the clamping plate continues, the clamping frame swings out about its bearing pin on the carrying lever. At this time the edge engaging the work moves away from the hold-down device.

Abstract: A method and apparatus for the pattern-correct sewing together of two pieces of cloth having the same pattern by a sewing machine with one cloth feed mechanism arranged over and one arranged under the cloth pieces, the feed quantity of which is variably by at least one positioning system relative to each other, uses a sensor arranged upstream of a stitch forming point for each cloth piece and a signal processing unit which processes signals from the sensors corresponding to the relative position of the cloth pieces and which influences the positioning system for the feed mechanism in accordance with the established relative position of the cloth pieces. For the pattern-correct sewing together of the two cloth pieces, the pattern structure of each cloth piece is continuously determined by the sensors by measuring values of a structure-or pattern-typical criterion.

Abstract: A feed drive for the work holder of a zig-zag stitch group sewing machine comprises a rotatable cam plate and a work holder which is engaged with the plate and moved thereby within a rectilinear guide arranged adjacent the head portion of the sewing machine. The work holder is located adjacent the needle and it includes a driver plate which extends below the sewing machine arm portion and grips the workpiece from above. The cam plate is arranged in a standard of the machine and the work holder is driven by engagement of a sensing element in a groove of the cam plate which is connected to the work holder through a lever drive acting on a rotatable shaft arranged below the arm of the machine and connected with a crank and a link with a slide carrying the work holder which is disposed in a guide. The construction includes a seating for the workpiece which is movable parallel to the guide and is coupled with the driving plate.

Abstract: A method of interconnecting first and second material plies, each having one side coated with a thermoplastic material uses pressing means in the form of continuously rotatable pressing rollers and heating means in the form of a heating gas. The marginal edge portion of an uncoated side of the first ply is folded back upon itself to form a pocket along its edge and after a strip of thermoplastic material or a strip having thermoplastic coating on each side is folded lengthwise, it is inserted into the pocket. The marginal edge portion of a thermoplastically coated face of the second ply is then positioned over the folded-over marginal edge portion of the first ply. Thermoplastic material between the folded-over portion of the first ply and the marginal portion of the second ply and between the folded portions of the strip are then heated so that they become thermoplastic and they are pressed together to press the portions to be bonded together.

Abstract: A sewing machine assembly comprises a work holding device which is mounted in a fixed location on a support such that a sewing machine carriage frame is movable toward and away from the workpiece holding device. The sewing machine carriage frame carries a support for the sewing machine which is movable transversely relative to the workpiece holding device by cog belts which are driven by a rotatable motor so that the sewing machine support moves backwardly and forwardly. The sewing machine is also mounted on a resilient support of a plate and an eccentric motion is imparted to the sewing machine by a driving motor and an oscillatory motion is imparted to the sewing machine in addition to its relative movement in respect to the holding device.

Abstract: A sewing machine for automatically making edge-parallel seams comprises a scanning device for recognizing the geometric form of the workpiece edge and a pressure piston lowerable laterally of the stitch formation point. For straight workpiece edges extending at an angle to each other, the pressure piston, having been lowered onto the workpiece with the sewing machine stopped, is rotated around the needle which is inserted in the workpiece, the workpiece being taken along accordingly. For a convexly arcuate edge pattern, first the lateral distance of the pressure piston from the needle is readjusted in such a way that it corresponds to the radius of the edge arc (e.g. scallop). Thereafter, with the sewing machine continuing to run, the pressure piston is lowered, whereupon the feed dog of the sewing machine rotates the workpiece around the pressure piston.

Abstract: A thread cutting device for a lockstitch sewing machine having a rotary hook rotating in a horizontal plane, comprises a thread catcher which is pivotable in a horizontal plane and designed with a catch shoulder for needle and bobbin threads. The catcher cooperates with a stationary cutting tool as well as with a leaf spring which serves as a clamp for the end portion of the bobbin thread. The thread catcher is designed with a retaining shoulder by which the needle thread loop, upon being passed around the bobbin case, is caught and then released before being cut. The temporarily retained thread length substantially corresponds to the thread length which is pulled out sidewards while the thread catcher moves into its cutting position. Since no needle thread is thereby pulled off the thread supply by the thread catcher, only a minimum force is needed for moving the catcher.

Abstract: A method for approaching a predeterminable end point of a seam spaced from the edge of a workpiece, with a sewing machine which comprises an adjustable needle and lower transport, a sensor arranged before the needle and triggering the process for the positioning of the needle in the end point during passage through the edge, a pulse generator coupled with the main shaft of the sewing machine for the delivery of counting pulses for a pulse counter, and a micro-computer which controls the action of the feed means as a function of the pulses originating from the sensor and from the pulse generator. To execute a desired shortening of the length of one or more of the last stitches before the end point of a seam, the workpiece is moved back by the difference between the desired stitch length and the stitch length set by the setting device, before execution of the adjusted feed.

Abstract: A feed drive for a stitch group sewing machine includes a cam plate serving to drive a work clamp. The cam plate is connected to a controllable clutch driven from the drive motor of the sewing machine. In order to keep the stitch length constant at varying lengths of the stitch group, the output speed of the clutch is controllable by a control device as a function of the rotational speed of the sewing machine of the transmission ratio of a gearing between the cam plate and the work clamp which determines the length of the stitch group, and of the adjusted stitch length. The stitch group to be sewn may be divided into two sections having their stitch lengths variable independently of each other, by providing that a switch responsive to a partial revolution of the cam plate corresponding to the length of the first section, alternately connects one of two potentiometers which determine the stitch length, to the control circuit of the clutch.

Abstract: A device for use with a sewing machine for making garments with pleats operates with a folded-over workpiece which is advanced past a reciprocating sewing needle and includes a pleating bar assembly which is insertable between the folds of the material and includes portions which engage against the folds of the material to hold a pleat in position while it is moved by a feed pressure member into a sewing position. The pleating bar assembly includes a supporting member such as a shaft or a rod having pleat members with bearing portions which are rotatable on the support member to permit the plates to be held in position and to be collapsed for bringing the pleat to a sewing position. The material is held by needle or pin members which engage into the material as it is fed into the sewing position.

Abstract: A lubricating system for sewing machines is produced with the sewing machine running by cutting a predetermined amount of cotton fibers into small lengths and blowing the fiber lengths into the sewing machine housing. As the fibers fill the housing a felt cushion conformable to the paths of motion of the parts of the mechanism is produced. The felt cushion is supplied with oil through a wick.

Abstract: A stop motion device for stopping the motion of a sewing, embroidering or tufting machine, comprises a pivotally mounted sensing lever having a sensing arm for receiving threads used by the machine. The sensing lever is also engaged with a switch for deactivating the machine when the lever is pivoted into a position to disengage the switch. A fixedly mounted guide is provided for guiding the threads at a location spaced from the sensing arm in the feed direction for the threads. Either the sensing arm or the guide includes one bore for guiding all the threads while the other includes two offset bores each for receiving at least one thread. The offset bores are offset perpendicularly with respect to the feed direction and with respect to the other single bore. When one of the threads breaks, the tension of the remaining threads causes the sensing lever to pivot and thus activates the switch to stop the machine.

Abstract: A drive mechanism for connecting a drive shaft of a sewing machine to a plurality of reciprocatable needle bars which are advantageously mounted in a single guide frame for reciprocation in the machine includes a link connection for each bar. The link connection includes an oscillatable two armed lever for each bar. It has an input arm driven by a shaft mounted in the machine for oscillation about a fixed axis and an output arm connected to a first link of a cooperative pivotally interconnected first and second link pair. An actuator shaft for each bar carries a respective actuator crank which in turn is connected through a link of relatively short length to the upper ends of the needle bars by a pivotal connection.

Abstract: A sewing machine with a drive for a work clamp comprises two slides movable relative to each other, one carrying the work clamp and the other carrying two tail wheels and an endless belt trained thereabout. Two stepping motors which can selectively be run in the same or in opposite directions are engaged each with a respective one of the belt strands, so that with the motors running in opposite directions, the two slides move in the lengthwise direction, while with a run in the same directions, only the slide directly carrying the work clamp is moved, namely transversely. In another embodiment, the slide directly carrying the work clamp is non-rotatably connected to one of the tail wheels.

Abstract: A thread changing mechanism for sewing machines includes a magazine in which a plurality of needle holders is received, to be positively coupled to the sewing machine needle bar by a vertical motion of the magazine. Upon effecting a coupling, the magazine is retracted into a starting position remote from the needle bar, so that the needle bar with the needle holder can unobstructedly move during the sewing operation. The thread changing mechanism is mounted on a sewing machine as an attachment later, without particular adjustments. When the needle holders are held in the magazine the thread is engaged with each needle and held out of the way of the operating needle thread.

Abstract: A device for stopping the machine drive of a needle movable in cooperation with a rotary hook of a sewing, embroidering or tufting machine upon a thread breakage comprises a thread cutting mechanism which includes a thread catcher movable through the needle path and a switching mechanism which is connected to the drive for disconnecting it and which becomes effective upon a thread breakage. The device includes a movably mounted thread feeler carrier having a thread feeler which is adapted to be located between the needle and the rotary hook. The drive mechanism for actuating the thread catcher includes control cams which are engageable with lifting cams so as to project the feeler out of the path of motion of the thread between the needle and the rotary hook. The thread feeler is associated with a piezoelectric element and the deflection of the feeler by the thread produces a pulse which regulates the drive mechanism for the sewing machine and effects the stopping thereof when the threads are cut.

Abstract: A sewing assembly equipped with a feed mechanism comprises a work holder which is supported by two swing arms hinged to each other, and moved by two stationary positioning motors. Each of the positioning motors is in positive drive connection with a slide carrying one of the swing arms. The swing arm directly carrying the work holder comprises a non-buckling center bar, a cross bar, and two prestressed spring steel strips by which the ends of the cross bar are connected to the end close to the swing axis of the center bar. The two member linkage with the stationary motors and the light-weight and yet non-bending swing arm result in a very low inertia of the feed mechanism.

Abstract: A material presser device on a sewing machine, includes a presser foot which is attached to a vertically movable presser bar and to which lift movements are imparted by a swing mechanism driven by the main shaft acting through a knee-joint transmission which, in its extended position, extends substantially in the movement direction of the presser bar. For positive connection of the presser foot with the swing mechanism, the presser bar is articulated via an intermediate pitman to one end of the connecting rod of a four-joint transmission. The other end of the four-joint transmission is connected by a connecting rod with an abutment which applies under the action of a spring, against a counter abutment secured to the housing. The connecting rod is connected to the knee joint transmission, the knee joint of which is connected to the sewing machine.