摘要:
By means of this method and apparatus for sewing a seam, it is possible to end a seam exactly at a predetermined location. When the predetermined location is reached, the forward movement of the sewing material is interrupted, and only the stitch that had been begun at the time of the interruption is completed. In this way, on the one hand, visually attractive seams can be produced and, on the other hand, it is possible to sew a small part onto a main part with a seam which does not extend past the small part.
摘要:
A button feeding device includes a button alignment shaft having a longitudinal axis which is displaceable with respect to the longitudinal axis of the main drive shaft. The button alignment shaft and the main drive shaft are advantageously linked for rotation by a coil spring. The device has a pin holder which aligns the button and transfers it into a button clamp, a carriage being provided to move the pin holder over a substantially linear quadrangular path.
摘要:
A fully digital control system for the speed of the arm shaft of a sewing machine provides separate counters for counting a counting frequency during the pulses and pulse intervals of a lower frequency increment generator measuring the actual value of the shaft speed. The inverse of the last complete count thus registered is compared with a set point value in a microcomputer preprogrammed with data blocks representing these set point values and provided with parameters for the respective keying ratios associated therewith. The control bus and data bus connecting the counters with the microcomputer also connect the latter to another unit including a bit-rate generator and a programmable retriggerable multivibrator from which the digital output signal is emitted to effect direct control over a DC motor or to drive a clutch connected to the shaft.
摘要:
The disclosure concerns a drive device for a double thread chain-stitch buttonhole sewing machine. The machine has a first drive shaft for driving the sewing needle and for moving the cloth support plate for sewing. It has a separate worm shaft for moving the cloth support plate to the sewing position and also for operating a knife for cutting the buttonhole. A first respective electromagnetic clutch operates the sewing needle drive shaft, and a second respective electromagnetic clutch operates an intermediate shaft which then operates the worm shaft for operating the cloth support plate and knife operating shaft are provided. A drive shaft is connected with the armature part of the first electromagnetic clutch on the sewing needle driving shaft. That armature part is gear connected with an armature part of the second clutch on the intermediate shaft. Activation of the clutches controls which of the shafts operates, as the clutches include rotors which rotate with respect to their respective shafts or are clutched to cause rotation of the shafts.
摘要:
A thread guide is used in combination with a standard sewing machine having a work table and a fabric feed for displacing a workpiece to be sewn on the table in a predetermined forward longitudinal direction through a sewing station on the table. The fabric guide comprises a transversely elastically deformable band extending generally in the workpiece-displacement direction and oriented on edge and holders engaging the band at a plurality of longitudinally offset locations for securing the band on the table with each of the locations in any of a multiplicity of transversely offset positions. Thus the band can be deformed into and held in a nonstraight shape. The guide further has a carriage displaceable on the table along the guide and provided with a clip fastenable on the workpiece, and a counterweight urging the carriage and clip longitudinally in a backward longitudinal direction opposite the forward longitudinal direction. The band is a ribbon of flexible spring steel that is longitudinally substantially inextensible and that is only deformable transversely to its plane.
摘要:
A sewing machine having an edge guide for producing a stitched seam along an edge of a workpiece terminating at another edge forming an angle with the first has an optical device for directing a pencil or beam of light toward a reflective surface which underlies the workpiece and is covered thereby until the movement of the workpiece exposes the reflective surface at this other edge. The optical detector then produces a signal for initiating a control function, e.g. the change of stitch pattern to tie off the end of the previously sewn seam or to lodge the needle in the fabric so that the workpiece may be turned to bring the other edge into contact with the edge guide. The control system can include a programmer for the successive stitching operations which are initiated in succession in response to the optical sensor.
摘要:
A circulating conveyor, e.g. of the type in which a load carrier passes along an endless track and supports material to be conveyed, e.g. garments suspended by hangers from the load carrier, comprises in addition to the circulating track, a load carrier which runs with a plurality of wheels on the endless rail and has a displacement chain formed by a multiplicity of rigid links each constituted by a rigid bar hinged at its ends to the adjoining links. The lateral flanks of the bar are engageable by a friction drive roller and a counter roller to displace the chain and hence the load carrier along the circulating path.
摘要:
A workpiece is held down against a support surface by a holddown foot. Then a feed foot is brought into engagement with this workpiece with its displacement speed decreasing continuously and uniformly until the feed foot comes to a stop against the workpiece, pressing it against the support surface. Thereafter the holddown foot is raised away from the workpiece and the feed foot slides the workpiece a predetermined distance along the surface toward the sewing station. The holddown foot then is brought into engagement with the workpiece on the surface, again with its speed decreasing uniformly and continuously until it comes to a stop on the workpiece. The feedfoot is lifted away from the workpiece and brought back into a position to advance it again. Each of these feet is carried on a rod pivoted of a ternary link guided on a frame and having its remaining pivot connected via a rigid lever also pivoted on the frame and oscillated back and forth by an eccentric arrangement operated by the drive shaft of the sewing machine.
摘要:
A device in a sewing machine for applying a variable downward force to a presser bar. A guide lever engages the presser bar and in turn is urged downward by the force of a spring. The bottom of the spring is held fixed to a lock sleeve on the guide lever. The top of the spring is fixed to a sleeve on a shaft which is disposed vertically inside the spring. The shaft passes freely out the bottom of the spring and through the guide lever without engaging either of these. The shaft and thereby the top of the spring are urged downward by a controllable pneumatic device in order to set the compression of the spring and thereby the downward force applied to the pressure bar by the guide lever. The pneumatic device preferably includes a pair of separately controlled pneumatic pistions arranged in series for moving the shaft to at least two predetermined positions.
摘要:
A sewing machine adapted for moving a workpiece in a downstream direction for sewing a seam therein, and for automatically terminating the seam at a predetermined point a selected distance from a trailing edge of the workpiece. An edge sensor on a base is located a predetermined distance upstream of the sewing point for sensing the downstream passage of the trailing edge, and generating edge sensing signals in response thereto. A stroke sensor on the base senses the length of the strokes of the feed dog and generates stroke length signals which are indicative of the stroke length and of the length of the stitches. A stopping device is provided on the base for being actuated to engage the workpiece to stop its movement when the sewing needle is at the predetermined point for terminating the seam; and a control system receives the edge sensing signals and the stroke length signals, determines therefrom a time when the sewing needle will be at the predetermined point, and generates a stopping signal for actuating the stopping device at that time.