Abstract: In a sewing machine provided with a thread supply stopping device for selectively controlling supply of a needle thread between a needle thread supply source and a take-up lever, an adjustable pre-tension exerting device exerts a tension equal to or lower than a tension of a bobbin thread on the needle thread between the needle thread supply source and the thread stopping device.
Abstract: The invention relates to a method of controlling an upper thread in a sewing machine. The sewing machine includes a needle holding the upper thread and vertically movable in association with a spindle, a loop taker holding a bobbin case carrier having a lower thread and rotatable in association with the spindle for forming a lock stitch in cooperation with the needle, and a thread take-up lever vertically movable in association with the spindle for loosening or taking up the upper thread. For a period of time from a moment at which a loop of the upper thread is released from a loop taker to a moment at which stitch tightening is completed, a tension required for stitch tightening is rendered to the upper thread.
Abstract: A lockstitch sewing machine is provided with a thread handling device comprising opposing lengths of cloth that receive and frictionally engage thread therebetween to maintain the takeup of the machine thread and impose restraint upon the descent of the thread when the takeup is moved downwardly from a stitch setting position.
Abstract: A sewing machine is provided with a thread handling device including an elongate rigid member and a strip from which resilient fibers extend outwardly to contact thread passing between the rigid member and strip, and with a thread engaging cam which prevents a premature descent in said device and improperly formed stitches resulting therefrom.
Abstract: A thread handling device including an elongate rigid member and a strip with fibers extending outwardly to contact thread in a sewing machine passing between the rigid member and strip is provided with bracketing thread controlling cams which improve the performance of said device.
Abstract: A sewing machine is provided with a thread handling device having a thread holding and a thread metering function. The device includes a pair of parallel elongate members, and a length of easily compressible resilient material which is carried by one of the members and compressed against the other member. Needle thread extending between the resilient material and said other member is subjected to frictional resistance by the resilient material during movement in the device.
Abstract: The present invention relates to an improved thread control mechanism for chain-stitch sewing machines. The present invention is adapted to apply a quick and effective clamping action to the sewing thread of the machine in timed relation with the rotary or oscillatory movements of the stitch forming instrumentalities. The mechanism's clamping force magnitude may be selectively regulated to exceed the tensile strength of the particular thread being used and is effective to break the thread should it become wound about an operable rotary shaft of the machine. The present invention includes a rotary actuating member for moving a thread engaging member between two extreme positions so as to entrap and intermittently clamp the thread at a location interposed between the stitch forming instrumentalities and the thread supply source.
Abstract: A thread handling system for a sewing machine is provided with a tensioning device without a check spring, a thread takeup member for pulling thread from the tensioning device and setting stitches, and a thread holder including a pair of elongated members which grasp and meter thread to a needle and looptaker. The tensioning device is disposed with respect to the operating limits of the takeup member to enable thread to be withdrawn from the tensioning device without being pulled from the thread source and with only slight thread tension.