Abstract: In a cover stitch sewing machine which forms double chain stitch seams, needle threads are pulled out from the needle thread tensioning devices, passing over a thread hanging point on a needle thread pulling-up spring and the needle thread take-up completes drawing-up of the needle threads after needle thread loops of the respective needles are seized by the looper. The sewing material is then fed one feed pitch as the needles are moved down and the needle thread take-up draws out the needle threads, while the needle threads are pulled up at the thread hanging point by the elasticity of the needle thread pulling-up spring, thus preventing slack in the needle threads below the needle thread eyes. The threads which are connected with the needle thread loops, are drawn up by the thread hanging point of the needle thread take-up against the resiliency of the needle thread pulling-up spring.

Abstract: A regulating mechanism for needle thread between a standard thread tensioning device in the head of the upper arm of a sewing machine and the eye of the reciprocable needle employs a lever-shaped takeup member which is oscillated in the head in synchronism with the movements of the needle, and a wire spring which is mounted directly on the takeup member. The spring has a U-shaped thread engaging portion which surrounds and cooperates with a hook-shaped arm of the takeup member to define a passage for needle thread. The spring tensions the thread during certain stages of each stitch forming step.

Abstract: A thread take-up device comprising a loop tightening member adapted to reciprocate within a predetermined range limited by a thread slackening limit position where the loop tightening member is located when a thread loop is expanded to its maximum extent by a loop-seizing member, and a loop tightening limit position for tightening the thread loop; and a movable member adapted to reciprocate within a predetermined range limited by a stopping position defined within the range of reciprocation of the loop tightening member above the loop tightening limit position, and a position corresponding to the thread slackening limit position of the loop tightening member. The respective loci of the recess for engaging the needle thread of the loop tightening member, and the thread catch of the movable member overlap each other.

Abstract: A slit (7) is formed which lies in a vertical plane and extends from an upper surface of a sewing machine frame (1) to a front surface. A tension device (5), a thread take-up spring (30), and upper and lower thread guides (23, 24) are disposed along the direction in which the slit (7) extends. A thread take-up lever (12) is installed so that it is reciprocated horizontally across the space between the pair of thread guides (23, 25). The placement of the thread in the tension device (5), thread take-up spring (30), and two thread guides (23, 24) can be attained by simply pulling the upper thread vertically downward through the slit (7). When the thread take-up lever is reciprocated, during its forward stroke it arrests the portion of the thread positioned between the two thread guides (23, 24) and draws it in V form. During its return stroke, the thread take-up lever (12) releases the thread to allow the latter to loosen in loop form.

Abstract: A thread take-up arm drive means for a multihead embroidery machine in which identical heads have automatic color change capability such that the color thread stitched on the plurality of embroidery heads is changed substantially simultaneously. A sliding carriage associated with each head contains a plurality of associated color stitching sets of thread take-up arms and needle bars. Each color stitching set is for stitching a different color thread. A computer controls a step motor to position the carriage and thus place the particular color stitching set in contact with the drive means. The thread take-up arm drive means is a pushplate biased in an up position by a leaf spring having adjustable tension. A cam follower is attached to the pushplate and moves the pushplate cyclically under force of and according to the design of the periphery of a cam. The cam is attached to the drive shaft that drives both the thread take-up arm and the needle bar of a color stitching set.