Abstract: Overedge crochet stitching provides a whip stitch appearance on both sides of a fabric. Each stitch has (a) two contiguous legs of thread on the upper surface of the fabric, extending from a needle hole to the edge of the fabric; and (b) two contiguous legs of thread on the lower surface of the fabric, extending from the needle hole to the edge of the fabric. Both legs on the upper surface are bent to form a two strand bight at the edge of the fabric. Both legs on the lower surface extend first through the two strand bight of the preceding stitch and then to a one strand bight which loops around the two strand bight of the current stitch. The method and apparatus involve a threaded needle which carries the thread through the fabric, a hook which pulls thread to the fabric edge above and below the fabric, and a retractable spreader which supports a leg of thread which extends up from the needle hole to the preceding stitch.
Abstract: A radially facing circumferential surface of a cam, in at least some planes which radiate from the cam axis, includes lines which are inclined relative to the cam axis. The inclinations of these lines vary from one axial plane to another, except in the dwell regions of the cam. A wobble member is supported for oscillating movement about a wobble axis. One or more cam followers on the wobble member engage the cam on opposite sides of a transverse reference plane which is substantially perpendicular to the cam axis. During operation of the mechanism, the cam turns about its axis, and the wobble member oscillates about its axis. The mechanism is used in a sewing machine to move a looper.
Abstract: A sewing machine has a housing and a mechanism in the housing for actuating the sewing elements of the machine. The mechanism includes a rotating shaft with a drive end which protrudes from the housing and carries a handwheel. The handwheel has a surface which is proximate to the housing to provide a thin space between the surface and the housing. Wheel rotation during machine operation causes centrifugal movement of air in the space toward the circumference of the space. The wheel has openings which supply air to the space to cool the wheel and prevent the aspiration of fluids from the housing by the centrifugal movement of air in the space.
Abstract: A sewing machine has a movable feed member for feeding articles to a stitch-applying station, and a trimmer for cutting chains of stitches which dangle from articles on the outfeed side of the stitch-applying station. The feed member and trimmer are driven from the same drive shaft. The trimmer drive includes a swinging crank which is connected to a rotary cam by a one-way clutch, one-way clutches which support the rotary cam and permit it to rotate only in the direction it is driven by the crank, and a rocker arm which has one end driven by the cam and another end drivingly connected to the trimmer.
Abstract: Noise and vibration are reduced in an axial cam drive mechanism by spring loading the rotary cam assembly to one end of its limit of axial travel. The spring load is applied through an antifriction axial thrust bearing, and is reacted by a second antifriction axial thrust bearing. The spring load applied exceeds the axial component of the maximum reaction load applied by the cam driven mechanism during operation so that there is no tendency of the rotary cam assembly to shift axially upon reversal of the reaction load.
Abstract: A thread control mechanism for an overedge sewing machine uses only the movable driven components of the needle, lower looper, and upper looper, in combination with stationary thread guides, for feeding and controlling the threads used by the machine to form a seam. The lower and upper looper threads, i.e., the threads which pass through the eye of the lower and upper loopers, respectively, are each engaged by movable thread guides carried on the looper carriers for both loopers so that the coordinated movement of the two loopers cooperate to control and feed both looper threads. A needle thread takeup cam mounted on and driven by the needle arm drive shaft cooperates with stationary thread guides to feed and control the needle thread.
Abstract: A trimming mechanism for an overedge sewing machine includes an elongated cutter arm driven in oscillatory movement to drive a movable cutting blade which cooperates with a fixed cutting blade to trim material passed through the sewing machine. An improved cutting blade mounting means is provided for simultaneously mounting the movable cutter blade on the driven cutter arm and automatically aligning the movable blade for cooperation with the fixed blade.