摘要:
A sewing machine for sewing buttonholes in a workpiece comprises a stationary lower part and an arm having one end pivotally mounted on the lower part and having an opposite end which carries a rotary hook which cooperates with a reciprocating needle carried in the lower part. The arm is pivotal relative to the base part to move the arm from a fixable sewing position with said hook spaced by a predetermined distance from the needle at a stitch-forming area to a rest position in which it is spaced away from the stitch-forming area. A thread-monitoring device is located adjacent the needle for monitoring the thread and detecting any breakage thereof. The machine includes a buttonhole cutting mechanism which is connected to the drive means so as to periodically cut the workpiece. A clamp is carried by the upper arm and it has a lower portion which rests on a resilient support which is biased upwardly by a spring. The upper part of the clamp carries a rod which is biased downwardly by a spring having a lower characteristic than the spring biasing the arm upwardly, and it engages over a presser frame to urge the frame into engagement with the workpiece. A locking mechanism is associated with the support upon which the lower clamping part rests, and it is effective to lock the support arm in a selected position whenever it is actuated by the thread monitor.
摘要:
The control circuit of a catch thread device has a counter for the main shaft of the swing machine. The counter counts the number of revolutions of the main shaft 26 during the reception of one of at least two signal intensities and is reset to its initial value when this signal intensity changes to the other signal intensity. When a predetermined maximum number of revolutions is reached, the counter emits a signal indicating a thread fault.
摘要:
A sewing device for producing form seams is usable with a sewing machine having a needle which reiprocates in respect to a cooperating rotary hook. The sewing machine also includes a guide mechanism for guiding a workpiece along a path corresponding to the configuration of the form seam in respect to the needle. The device includes a workpiece support member having a stitch hole for the passage of the needle and a force-away surface bounding the stitch hole. The device includes a plate which is mounted so that the force-away surface is disposed between the needle and the rotary hook and it is mounted for vertical movement and horizontal oscillatory movement. The actuating means for the device causes a movement of the force-away surface in timed relationship to the reciprocation of the needle and in accordance with the movement of the workpiece in a direction opposite to the movement of the workpiece with respect to the needle and the rotary hook.
摘要:
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. For the exact control of the insertion of the needle into the predetermined end point, the microcomputer is connected with a displacement system for an abutment for the presettable limitation of the movement deflection of a follow-up element coupled with the positioning gearing and with a servo system moving the latter against the abutment. For feed reversal immediately after execution of the stitch formation in the end position, the follow-up element is coupled with the positioning gearing through a freewheel coupling. To prevent displacement of the abutment by reaction of the forces occurring when the stitch length is shortened, the displacement system is connected with the abutment through a self-locking gearing.
摘要:
A pocket stitch is sewn on cut workpiece parts which are guided into operative association with a reciprocating needle which effects a straight stitch when it is reciprocated and also may be swung from side to side to effect a zig-zag stitching. The workpiece is guided so as to form at least one substantially U-shape straight stitch having spaced apart leg portions and the stitch is secured by guiding the workpiece to effect the formation of a barring stitch at the ends of each leg portion by causing the needle to form a zig-zag stitch at such location. The sewing machine for sewing the pocket cuts includes a needle bar which may be swung during the operation of the drive mechanism or the zig-zag control mechanism may be shifted to effect the formation of a straight stitch. A rotatable cam which is driven by the drive mechanism positions a clamping plate having a substantially U-shape slot which permits reciprocation of the needle through a workpiece carried thereon. The cam includes means for controlling the swinging of the needle to effect the zig-zag stitching and for controlling the straight stitching operation of the needle and it also has means for controlling the shifting of the workpiece to follow the outline. The device can also effect the formation of a double U-shaped stitch in which the U-shape portion is formed by two spaced apart straight stitches and a barring stitch is used at each end of the leg portions which is formed by a zig-zag stitch which is effected transversely to the straight stitches.
摘要:
A processing and sewing machine arrangement for preparing a seam which is uninterrupted on a seam side facing the needle of the sewing machine. The arrangement includes a shuttle thread disturbance detection arrangement and a control arrangement activating a stopping arrangement for stopping the sewing machine after the shuttle thread disturbance has been detected and after a stitch formation cycle which has been begun is completed. A regulating mechanism for setting stitch length is set into a reverse stitching mode by the control arrangement while the fabric being sewn is moved backward by one stitch length. After the shuttle thread has been fed in, thread is knotted by at least one stitch with the needle thread in the same insertion hole in which the old shuttle thread is located such that the old shuttle thread is correctly knotted with the needle thread.
摘要:
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.
摘要:
A method of sewing the corners of a double seam, employing a two-needle machine the two needle rods of which each may be mutually independently engaged and disengaged. The method uses control means to arrive at the corner point of the inner seam, disengaging the internal needle rod, furthersewing to the corner point of the outer seam, stopping the sewing machine with the outer needle penetrating the workpiece, then rotating the workpiece, sewing the thus rotated outer seam, and engaging the inner needle rod. The sewing machine comprises at least one adjustable feed dog means, at least one sensor which is disposed ahead of the needles and which triggers the process of positioning the respective needle at the corresponding corner point, said triggering occurring when the edge of the workpiece passes said sensor, a pulse generator coupled to the main shaft of the sewing machine, which pulse generator provides counting pulses for a pulse counter, a microcomputer which controls the operation of the feed dog means in accordance with pulses emitted by the sensor and the pulse generator.To avoid a shortened stitch in the outer seam when forming stitches with the two needles in the region of the corner point of the inner seam, the stitch formation is carried out in two stitch forming cycles, in the first cycle stitch formation by the outer needle rod is prevented, and the advancing is reduced to the stitch length required to reach the corner point of the inner seam, and in the second cycle the inner needle rod is disengaged and the advancing is reduced to the distance comprising the difference between the normal stitch length (as set) and the stitch length executed in the first cycle.
摘要:
An arrangement for monitoring the shuttle thread reserve in a sewing machine with a lockstitch revolving shuttle and with a light-emitting diode, which sends a beam of light through openings in the bobbin housing and in the bobbin to a photodetector which triggers a switching pulse for an actuating device. To obtain maximum utilization of the residual thread, the photodetector is used at the same time as a pulse generator for a counter which controls the actuating device. The counter can be connected to a switch-off device of a drive motor for the sewing machine.
摘要:
A pocket stitch is sewn on cut workpiece parts which are guided into operative association with a reciprocating needle which effects a straight stitch when it is reciprocated and also may be swung from side to side to effect a zig-zag stitching. The workpiece is guided so as to form at least one substantially U-shape straight stitch having spaced apart leg portions and the stitch is secured by guiding the workpiece to effect the formation of a barring stitch at the ends of each leg portion by causing the needle to form a zig-zag stitch at such location. The sewing machine for sewing the pocket cuts includes a needle bar which may be swung during the operation of the drive mechanism or the zig-zag control mechanism may be shifted to effect the formation of a straight stitch. A rotatable cam which is driven by the drive mechanism positions a clamping plate having a substantially U-shape slot which permits reciprocation of the needle through a workpiece carried thereon. The cam includes means for controlling the swinging of the needle to effect the zig-zag stitching and for controlling the straight stitching operation of the needle and it also has means for controlling the shifting of the workpiece to follow the outline. The device can also effect the formation of a double U-shaped stitch in which the U-shape portion is formed by two spaced apart straight stitches and a barring stitch is used at each end of the leg portions which is formed by a zig-zag stitch which is effected transversely to the straight stitches.