Abstract: A high frequency sewing machine for intermittently transferring a work material mounted on a work material mounting plate by means of feed dogs which perform synthetic circular movement in horizontal and vertical directions and which cooperate with a presser foot to effect the continuous bonding of the overlapped portions of a fiber cloth which are continuously bonded together by means of a thermoplastic resin tape held between the overlapped portions of the fiber cloth in the work material to melt under high frequency dielectric heating. High frequency power is applied between a pair of planar electrodes respectively disposed above and below the work material during the time when the transfer by these feed dogs is stopped to effect the melting process. The occurrence of defective products having burn or the like due to heat concentration can be prevented while obtaining assured uniform bonding strength by using the high frequency power.

Abstract: A high frequency sewing machine for intermittently transferring a work material mounted on a work material mounting plate by means of feed dogs which perform synthetic circular movement in horizontal and vertical directions and which cooperate with a presser foot to effect the continuous bonding of the overlapped portions of a fiber cloth which are continuously bonded together by means of a thermoplastic resin tape held between the overlapped portions of the fiber cloth in the work material to melt under high frequency dielectric heating. High frequency power is applied between a pair of planar electrodes respectively disposed above and below the work material during the time when the transfer by these feed dogs is stopped to effect the melting process. The occurrence of defective products having burn or the like due to heat concentration can be prevented while obtaining assured uniform bonding strength by using the high frequency power.

Abstract: A thread supplying device includes a rotator feeding a thread downstream of a thread supply path, the rotator winding a periphery thereof the thread several times and locating in the path extending from a thread supply part to a needle and loopers, a stepping motor continuously drivingly rotating in one way the rotator in synchronism with the main shaft of a sewing machine, thread feed setting means setting a unit thread feeding amount necessary for formation of seams per stitch, and control means automatically controlling the rotation of the motor to feed the unit thread feeding amount set by the setting means for each formation of seams per stitch. This device can stably supply a predetermined amount of the unit thread, and achieve stabilization of stitch performance, irrespective of the type of the thread, and whether the feed of a fabric increases or decreases by a rapid change in the rotational speed of the sewing machine.

Abstract: A thread supplying device includes a rotator feeding a thread downstream of a thread supply path, the rotator winding a periphery thereof the thread several times and locating in the path extending from a thread supply part to a needle and loopers, a stepping motor continuously drivingly rotating in one way the rotator in synchronism with the main shaft of a sewing machine, thread feed setting means setting a unit thread feeding amount necessary for formation of seams per stitch, and control means automatically controlling the rotation of the motor to feed the unit thread feeding amount set by the setting means for each formation of seams per stitch. This device can stably supply a predetermined amount of the unit thread, and achieve stabilization of stitch performance, irrespective of the type of the thread, and whether the feed of a fabric increases or decreases by a rapid change in the rotational speed of the sewing machine.

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 moveable 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 nip 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 needler 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: Provided is a presser foot system for sewing machine comprising a small tubular cylinder bed which is used, for example, in joining crotch sewing of underpants or drawers and joining shoulder sewing of shirts. Distance from the center of a needle location to the cutting starting position of a knife trimming mechanism, wherein the upper edges of the ends of fabrics in a vertical face-to-face contact to be fed to a guide path are cut to an even length, is set to the range of 16.5 mm to 18.0 mm in actual dimension. This range is sufficient so that the ends thus cut by one operation of the knife trimming mechanism are stacked one on another by the operation of guide of upper and lower guides until these reach the needle location. Thus, irrespective of the thickness and flexibility of the fabric material and the presence or absence of a step, the ends of the fabrics cut to the even length can be fed in a predetermined stacked state to the needle location, thereby ensuring high quality finish of sewing.

Abstract: A thick fabric of poor surface smoothness, such as a fabric for wet suit, can be fed reliably, smoothly and uniformly to perform sewing of excellent finish, without requiring any oil application to the fabric surface before sewing, by arranging a presser foot body, a small presser foot and a roller as follows. The presser foot body is fixedly supported to a lower end portion of a presser bar supported to a sewing arm part so that it is free to move vertically and reciprocally. The small presser foot resiliently pressing the fabric to the upper surface side of a throat plate is disposed on the downstream side than a needle location hole of the presser foot body in the sewing direction. The roller is disposed on the upstream side than the needle location hole in the sewing direction and is rotatable such that its contact portion with the fabric is successively changed with the fabric feed.

Abstract: A thick fabric of poor surface smoothness, such as a fabric for wet suit, can be fed reliably, smoothly and uniformly to perform sewing of excellent finish, without requiring any oil application to the fabric surface before sewing, by arranging a presser foot body, a small presser foot and a roller as follows. The presser foot body is fixedly supported to a lower end portion of a presser bar supported to a sewing arm part so that it is free to move vertically and reciprocally. The small presser foot resiliently pressing the fabric to the upper surface side of a throat plate is disposed on the downstream side than a needle location hole of the presser foot body in the sewing direction. The roller is disposed on the upstream side than the needle location hole in the sewing direction and is rotatable such that its contact portion with the fabric is successively changed with the fabric feed.

Abstract: An interlock stitch sewing machine for blindstitch hemming with a slippage preventing device is provided which is so constructed as to prevent slippage that is likely to occur due to a position error of a lower fabric portion of the fabric portions stacked by a top-stitching at the fabric end, or a locally deformed portion due to a cutting error, in the blindstitch hemming of a tubular article such as T-shirts or underwear. A top-stiching width guide and a fabric edge guide are oppositely disposed in front of a needle location. A slippage detecting sensor that detects the edge position of the lower fabric portion to detect the presence of slippage, is attached to the fabric edge guide. When the slippage quantity detected by the sensor exceeds a permissible slippage quantity, it is determined there is possibility of slippage, and an informing means is operated.

Abstract: A sewing machine with a dust removing device prevents trouble such as faulty sewing caused when dust including waste thread and waste cloth is collected under a throat plate, in performing, for example, interlock stitch sewing by an overlock sewing machine. Specifically, an upward air introducing path is provided, through which the cooling airflow generated by a cooling fan actuated during sewing operation is fed to an air introducing path for oil cooling underneath a lubricating oil storage part, and, through which the cooling airflow passing through the air introducing path for oil cooling is blown up from the underside of a frame to a needle location of the throat plate, in order to blow up the dust. An opening of one end of a suction pipe for collecting dust attached to the frame is disposed sidewise above the throat plate.

Abstract: A strip matter cutting device for sewing machine is provided which is mainly employed in automatically cutting a tape or rubber sewed on the shoulders of a T-shirt. It is arranged such that the whole of a cutting part which comprises a rotary cutting blade and a tape receiving portion integrally formed with a tape pick-up portion, is shifted between a cutting action position closely adjacent to the rear of a needle location of a throat plate secured to the top surface of a sewing machine bed, and a non-action position at which the cutting part is retracted upward to the left of a sewing machine arm over the throat plate, through a rock arm which is driven to rock reciprocally by a rotary cylinder. Employment of this arrangement permits an improvement in work efficiency and a significant reduction in work burden. Even for a wide object to be sewed, it is fed freely for automatic cutting of a sewed tape or rubber, without the tape or rubber losses.

Abstract: Provided is a faulty sewing detector that is, for example, mounted on an overlock sewing machine, with which an over-edge chain stitch is made in a state in which a body fabric and a sleeve fabric of a T shirt or underwear are overlapped with each other. The detector comprises a fabric twisting detecting sensor that detects a fabric twisting by determining the number of overlap of fabrics sewed which is disposed at a position corresponding to the fabric sewing area of a needle, and, behind a needle location in a sewing direction; a faulty sewing judging means that compares a fabric twisting quantity detected by the sensor, with a preset permissible fabric twisting quantity, to judge it as faulty sewing when the former exceeds the latter; and an informing means that is activated when judged as faulty sewing.