Abstract: An automatic thread trimming device of a sewing machine contains: a holding disc, a cutter assembly, a fixed cutter, and a protective sheet. The automatic thread trimming device further contains an abutting segment formed on a distal portion of a curved section of a front end of an elastic extension and corresponding to a contact zone of a movable cutter, such that the movable cutter moves to the fixed cutter horizontally to produce cutting force. In the meantime, a longitudinal thickness of a protrusion corresponding to a receiving orifice is 0.5 mm so that a short thread end is cut between a thread and a cut portion of the thread, and the short thread end retracts inward because of a woven fabric, thus obtaining a flatness of a sewing product. Preferably, the automatic thread trimming device is capable of being driven by drive elements of any sewing machines.

Abstract: A camless automated thread cutting system for an electronic lockstitch pattern tacking sewing machine having a sewing needle driven by a main shaft and having a knife mechanism in proximity with the needle for cutting thread at the end of a pattern sewing cycle. The cutting system comprises a pneumatic cylinder for mechanically engaging the knife mechanism through a mechanical linkage in the machine, a solenoid-actuated air valve in fluid communication with the pneumatic cylinder, a programmable logic controller (PLC), and a pair of independently adjustable discs mounted on the main shaft of the sewing machine and operatively coupled to a proximity sensor which supplies an electrical signal to the PLC. The PLC is responsive to a machine signal indicative of the end of a sewing cycle and to the proximity sensor signal for generating a control signal for actuation of the valve so as to initiate and subsequently terminate a knife movement sequence at the end of the sewing cycle.

Abstract: Provided is a thread cutting device for sewing machine used when the operator performs a sewing operation while inserting an elastic cord in a circular part of a sewing object such as a waist part of underwear. When the sewing operation is completed, a movable thread guard member and a thread nip member nip a cut end of a looper thread cut by an existing thread cutting device. With a fabric feed immediately after the next following sewing operation is started in this state, part of a looper thread hanging between a flip position of the cut end and the fabric is cut under sliding contact at a location extremely adjacent to the starting position of seams by using a cutting edge, facing to a needle location, of a blade fixed to a throat plate. This permits a remarkable reduction in the length of the looper thread end remaining at the starting position of the seams.

Abstract: A bobbin assembly having a base wall, a center post projecting away from the base wall in cantilever fashion, a peripheral wall assembly which extends at least partially around the center post, a hook assembly and at least one of a) a thread cutting slot and b) a knife edge on the bobbin assembly. At least a part of the hook assembly is rotatable around a first axis to engage a thread and cause an engaged thread to be formed into a loop as an incident of the at least part of the hook assembly rotating around the first axis. The at least one of the a) thread cutting slot and b) knife edge on the bobbin assembly severs a thread which is formed in a loop by the hook assembly as the at least part of the hook assembly is rotated around the first axis in operation, which loop, if constricted, would wrap against the center post.

Abstract: The present invention relates to an under trimming device mounted below a needle late of a multi-needle sewing machine which mainly comprises an under trimming subassembly and a thread-sucking subassembly. The under trimming subassembly comprises a linkage and a thread-releasing means both being capable of shifting the under trimming subassembly into a standby position, extended position, thread-catching position, retracted and cut position, thread-clamping position, and a thread-releasing position in a series of linear movements. The thread-sucking subassembly is provided at one lateral side of the under trimming subassembly such that the looper thread cut and released by the under trimming subassembly can be instantly sucked and clamped in place and then used in the next sewing operation.

Abstract: An automatic bobbin thread guiding apparatus in combination with a sewing machine has a work supporting bed, a throat plate, a shuttle race slide and a horizontally rotating shuttle. A bobbin thread holding assembly is provided between the shuttle race slide and the rotating shuttle, for clamping and carrying the bobbin thread end, and is operatively connected with the slide. A bobbin thread engagement guiding mechanism is provided for guiding the bobbin thread catching portion of the assembly so as to make the bobbin thread engage automatically with the bobbin thread tension adjusting mechanism in the rotating shuttle when the assembly is driven backward, and then to hold the catching portion at a given position for making the bobbin thread intersect with the needle thread loop when the assembly reached its rear end position.

Abstract: A thread cutting unit cooperating with the bed of a sewing machine includes a lower shaft, a cutting knife and a loop spreading plate respectively fixed to the lower shaft and positioned adjacent to the hook. The thread cutting knife and the loop spreading plate cross each other in a space between the hook and the throat plate. The thread cutting unit is provided with a thread cutting driving unit which comprises a thread cutting knife driving shaft, a loop spreading plate driving shaft, a rotational motion transmission device, a thread cutting supporting member carrying thread cutting knife, a first turnable interlocking mechanism and a second turnable interlocking mechanism. The thread cutting supporting member is rotatably supported on the bed.

Abstract: A thread-cutting device for zigzag sewing machines for forming uniformly short thread ends regardless of the top stitch position of the last stitch. The thread cutter 28 is movable in a plane that is parallel to the thread catcher 33 and is connected by a drive unit 45 through 58 having stop sections 54, 55 to the drive of the thread catcher 33 such that the thread catcher can be moved, together with the cutter, into the cutting position located below the center of the stitch hole. While the thread cutter 28 stops in the cutting position, the thread catcher completes the thread separation process. The thread cutter 28 is moved back during the return movement of the thread catcher 33 only after the threads have been cut. The drive unit 45 through 58 for the thread cutter 28 is of positive-locking design, as a result of which even thick threads are cut reliably. The thread cutting device is particularly suitabloe for installation (even subsequent installation) in stitch group zigzag sewing machines.

Abstract: A buttonhole machine has a vertically reciprocal needle, a horizontally displaceable material support plate, a rotary stitch plate below the needle, mechanism for feeding a lower thread up through the stitch plate, clamps for holding material on the material plate at the stitch plate, and a drive for rotating the stitch plate in one rotational sense, simultaneously displacing the material plate, and reciprocating the needle to form a buttonhole in the fabric and for rotating it in an opposite return rotational sense after formation of the buttonhole. Such a machine also feeds an upper thread down through the needle to the stitching location and also normally lays a thick cording thread into the buttonhole to reinforce it. This machine is equipped with a feed arm carried by and jointly rotatable with the stitch plate, engaging the lower thread, and pivotal for freeing a length of the lower thread and feeding same to the stitch plate.