Abstract: The cloth clamp comprises a pivot arm provided with a clamp foot, which arm can automatically assume a closed position through a toggle lever drive, a setting lever connected therewith, and an extension spring acting on the setting lever counter to the force of a leaf spring packet acting on the toggle lever drive. An actuating mechanism is needed only for opening the cloth clamp.

Abstract: A feed drive for a stitch group sewing machine includes a cam plate serving to drive a cloth clamp and it is connected with a separate motor. In order to keep the stitch length constant at varying length of the stitch group, the motor speed 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 cam plate and cloth clamp which determines the length of the stitch group, and of the adjusted stitch length. The stitch group to be sewn can be divided into two sections with a stitch length variable independently of each other, in that a path-dependent switch operable after 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, with the motor control circuit.

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: An auxiliary needle is supported by a shiftable and rotatable slide rod which extends in a slightly inclined position relative to the vertical and is guided by an extension in a guide slot. The upper portion of the guide slot extends at an angle relative to the slide rod. Therefore, if moved from its rest position downwardly into its working position, the auxiliary needle performs first a combined rotary and translational motion, and then, upon penetrating a workpiece, only a straight longitudinal motion.

Abstract: A method of manufacturing pantyhose by means of sewing machine using hose shaped leg parts comprises arranging the leg parts in a flattened side by side longitudinal relationship, cutting each leg part along an edge from the waist rim of its panty area up to a crotch leaving a remaining leg portion of each leg uncut so as to form upper and lower plies of each leg cut along their inner opposite edges, sewing the cut edges of the laterally adjacent plies together from the waist rim to the crotch to form a seam, deflecting the outer plies outwardly to overlie the remaining leg portions and continuing to sew the seam by sewing in the same direction the edge portions of the upper plies together. A sewing machine carrying out the invention includes a presser foot having a sole with a toe shaped front part which engages into each leg portion of the pantyhose to be formed.

Abstract: A sewing machine with at least one feed means, the feed amount of which is variable by means of a positioning device acting on at least one positioning gearing; with a system for approaching a predeterminable end point of a seam in spaced relation to the edge of a workpiece; with a sensor disposed before the needle which during passage of the edge triggers the process for the positioning of the needle in the end point; with a pulse generator coupled with the main shaft of the sewing machine for the delivery of counting pulses for a pulse counter and a microcomputer which interrupts the action of the feed means as a function of the pulses emanating from the sensor and from the pulse generator in the end point.

Abstract: A method of manufacturing pantyhose by means of sewing machine using hose shaped leg parts comprises arranging the leg parts in a flattened side by side longitudinal relationship, cutting each leg part along an edge from the waist rim of its panty area up to a crotch leaving a remaining leg portion of each leg uncut so as to form upper and lower plies of each leg cut along their inner opposite edges, sewing the cut edges of the laterally adjacent plies together from the waist rim to the crotch to form a seam, deflecting the outer plies outwardly to overlie the remaining leg portions and continuing to sew the seam by sewing in the same direction the edge portions of the upper plies together. A sewing machine carrying out the invention includes a presser foot having a sole with a toe shaped front part which engages into each leg portion of the pantyhose to be formed.

Abstract: A sewing machine with a guiding device for the automatic sewing of a curved seam parallel to the edge. Provided are an edge guide ruler and a device with a first setting means to raise and lower a pressure pad disposed at a lateral distance from the needle and exerting a braking force on the workpiece and effecting, in interaction with the material feeder, the workpiece alignment motion. For more precise control the pressure pad is movable transverse to the workpiece direction by a second setting means to vary its lateral distance from the needle, and the setting means is controllable as a function of predeterminable part sections of the entire seam. This makes it possible to cause the pressure pad to contact the workpiece in the respective center of rotation of outside curves.

Abstract: A device for feeding and sewing a knitted ribbon to the edge portion of garment parts of a mesh material, to be provided with a U-shaped border trimming. To secure the position of the upper portion of the folded ribbon, a horizontal separating element is provided adjacent the vertical guide web of the presser foot which is associated with a lifting web extending laterally of and spaced apart from the guide web ahead of the needle. In the area closely adjacent the needle, a hold-down adjustable in height is provided between the lifting web and the guide web. The guiding edge and the foot of the hold-down are provided at different levels in order to slightly stretch the material and spread apart the meshes of the border.

Abstract: A thread changing mechanism for sewing machines comprises a plurality of needle holders which are received for displacement in a magazine which is fixedly mounted at the level of the top dead center of the needle bar. The needle holders have inner guide surfaces in T-configuration, corresponding to outer T-configuration guide surfaces of the coupling member which is secured to the needle bar. In the middle of the magazine, a recess is provided for the coupled needle holder. In a first embodiment, several fingers are pivotable between the needle holders to space them from each other. The coupled needle holder can then move freely upwardly and downwardly during the sewing operation. In a second embodiment, the same free movement of the coupled needle holder is ensured by a fork by which, after the coupling is effected, the needed spacing between the coupled one and the adjacent needle holders is ensured.

Abstract: A device for driving a sewing machine which includes a main shaft driven by a positioning motor that can be stopped in at least one predetermined position and then returned back to a second predetermined position, comprises a coupling disc which can be moved into engagement with a drive disc associated with the motor and a main shaft to drive the main shaft in a direction opposite to its normal direction of operation as determined by the positioning motor. The coupling disc is provided with cam surfaces with a cam engaging surface provided on a supporting member which is biased toward the disc by a predetermined tension. An actuator is connected to the support for rotating the actuator. The initial rotation moves the coupling disc into engagement with the driver disc which is connected to the main shaft, and the further rotation of the support rotates both the coupling and main shaft by a predetermined amount.

Abstract: A presser foot device on a sewing machine has a swingingly driven foot which can be shifted by two compressed air cylinders and piston combination and a spring mechanism into an inoperative position and, for adaptation to different work thicknesses, into a plurality of operating ranges, each with a different height position but constant amplitude of oscillation.

Abstract: A sewing machine includes a main shaft driving a sewing needle to reciprocate it through the material to be sewn which is fed over a needle slide of a stitch plate. The main shaft also drives a trimming knife drive which drives a reciprocating knife which cooperates with a counter blade adjacent the stitch plate for trimming the material. The trimming knife drive includes an eccentric driven by the main shaft and operating a knife operating linkage connected to reciprocate the knife. An eccentric rod is driven by the eccentric and it drives a swing lever through a guide rod which is pivoted thereto. The swing lever in turn drives the knife through a linkage connected between it and the knife and selectively moves it upwardly and downwardly for stopping its motion in either an upward or downward position.

Abstract: A device is disclosed for letting out hides which comprises a table having a longitudinally extending slot therein for supporting a hide, clamping jaws movable laterally of the slot to clamp a fold in the hide, and a parting sword raisable into the slot to form a fold in the hide and move it into the space between the jaws. One of the jaws is movable parallel to the longitudinal slot to offset part of the hide after it is cut. The parting sword is made up of a pair of side plates and an intermediate plate. One side plate which is adjacent the lengthwise movable jaw is also movable to facilitate the movement of the hide part therebetween into its offset position and the intermediate plate is movable vertically with respect to the side plates so as to form a slot between the side plates in a lowered position to facilitate cutting of the hide and, to permit the clamping of the hide parts using the clamping jaws, against the intermediate plate, with the intermediate plate raised above the side plates.

Abstract: A sewing machine for sewing shaped seams comprises equipment for exactly positioning an end stitch. By means of two edge sensing sensors provided one after the other in the feed direction, a pulse generator coupled to the main shaft, and a microprocessor, the difference between the desired feed length of the workpiece and the actual feed length thereof is determined. A microprocessor controls a step motor for adjusting a stitch setting device, the adjustment being a function of the difference between the desired and actual feed lengths of the workpiece and of the angular position of the main shaft at the instant of response of the second sensor. In this way, the length in excess of the last stitch which, without a correction, would extend beyond the predetermined end point, is uniformly distributed among the last stitches of the seam, while at the same time taking into account slippage between the feed dog and the workpiece.

Abstract: A sewing machine is with a device for producing corner seams comprising a sensor which is located ahead of the needle and which releases the operation of stopping the needle at a predetermined corner point as soon as an edge of the work passes by. To exactly control the sticking in of the needle at a predetermined corner location, a pulse generator for delivering counting pulses and coupled to the main shaft of the sewing machine, is connected through a switching element to a setting counter, and is effective only during the advance phases of the feed dog motion. In addition, the sensor is connected to the switching element to switch it on as soon as the oblique edge of the work passes by, and the setting counter is connected to a device for instantly stopping the advancing effect of the feed dog, and to a device for stopping the sewing machine in the lowermost position of the needle, to release the operation of these devices as soon as a presettable number of pulses is reached.

Abstract: A sewing machine includes a presser foot which is driven on a main shaft by an eccentric drive which drives through a toggle mechanism to a crank lever driver which effects the raising of the presser foot synchronously with the upward movement of a sewing machine needle so as to release a workpiece for movement relative to the needle. The presser foot is biased downwardly by a spring which may be adjusted as to its tension. During a sewing operation a driver is moved to a position only slightly disengaged from the lifting surface of the presser foot and during periods of engagement of the presser foot with the workpiece the toggle mechanism ensures that the presser foot engages the workpiece gently, irrespective of the adjusted amount of total lift of the presser foot by the drive mechanism.

Abstract: A sewing machine comprises a sewing machine support arm with a cloth feeding plate mounted on the support arm over which the material to be sewn is fed. A stop element is mounted on the support arm and it overlies the cloth feeding plate and it includes a portion which defines a material stop against which the material to be sewn may be positioned. The stop is made of a compressible material and it is compressible in the direction toward the feeding plate. A presser plate associated with the machine may advantageously be in the form of a button clamp may be moved downwardly into engagement with the stop which is raised slightly above the material and compress it downwardly until the plate clamps the material in place for the sewing operation.

Abstract: A setting mechanism for the feed dog of a sewing machine having a setting member secured to a setting shaft for determining the amount and direction of the feed movement for the feed dog, comprises a reversal lever which is pivotable between two end positions and biased into one of the end positions by a return spring. To be able to vary the setting torque by which the return spring opposes the setting motion of the reversal lever, the other end of the return spring is connected to the reversal lever through a linkage. This linkage includes an end member having its pivotal axis coaxial with the setting shaft. The torque of the return spring, which normally increases with the progressing pivoting of the reversal lever may be reduced by a linkage design wherein the torque acting on the reversal lever through this linkage reverses within the actuating range of the lever.

Abstract: An upper cloth feed in a sewing machine comprises a presser foot and an upper cloth feed foot, each connected over a linkage with a feeding and lifting drive. The drive is connected over a connecting member with a substantially vertically moving carrier for the presser foot. A spring acts on the connecting member, and an idle stroke connection is provided inside the lifting drive. For the adjustable distribution of the pressure force on the two sewing feet, the force of the spring acting on the substantially horizontally moving connecting member is variable. In order to obtain a simple constructional design, the spring presses over a pressure rod on a pressure piece mounted for displacement on the connecting member.