Patent GB-191209460-A (GB)
Title: Improvements in Stitch-forming Mechanism.
Inventor: FAIRWEATHER WALLACE
IPC: D05B3/02
Filed: 1912-04-22
Granted: 1913-05-22
Abstract: 9460. Fairweather, W., [Singer Manufacturing Co.]. April 22. Sewing - machines; double - loop stitching; governing needle and under threads.-In the formation of a two-thread over-edge stitch, the needle-thread loop cast by the needle in its overedge stroke is entered by a thread - carrying looper 59. The loop of the under-thread is retained by a cross-moving threadless looper 84 and is spread for the passage of the needle in its depth stroke. Finally the needle - thread loop cast in the depth stroke is engaged by a second threadless looper 60 which carries it to the edge of the fabric and there spreads it for the passage of the needle on the next over-edge stroke. After the engagement of the underthread loop by the cross - moving looper, the thread - carrying looper withdraws from the needle-thread loop and so permits the slack thread in the latter to be drawn up by the auxiliary take-up, while the needle is out of the work, and subsequent fouling of the loop by the needle is prevented. Also the depth stitch needle - thread loop is tightened round the shank of the needle when the needle is by the edge of the fabric. Thus the reeving of the thread through the needle eye does not take place when the needle is penetrating the work, and consequently only a light thread-tension is necessary. The looper 60 is provided with a finger 66 which is cam-actuated to spread the needle-thread loop of the depth stitch as shown in Fig. 13. In the application of the invention to a buttonhole - sewing machine, the loopers 59, 60 are secured opposite one another to a sleeve 56, Fig. 4, mounted upon a frame 53 carried by a revoluble pillar 52. The sleeve 56 is oscillated by link-and-lever connexion with a sleeve 96 which is reciprocated longitudinally by a cam-actuated slide 107. The loop-spreading finger 66 is operated by a fixed cam surface 74 on to which its shank is pressed by a spring. The looper 84 is mounted upon a transverse spindle 78 and is actuated by means of a pin and cross-slot connexion with a second sleeve 94 actuated by a cam-actuated slide 114. The frame 53 and the devices upon it are rotated in the stitching of a buttonhole by a rack 117 which engages a pinion 116 integral with the pillar 52. The looper-thread is controlled by a tension disk and a spring take-up secured to the stationary frame-work. The needle-thread is controlled by a tension disk, a take-up, an auxiliary take-up, and a thread lock. Needles, vibrating. - A needle-holder 23, Fig. 3, is pivoted between cone-pins in a frame 18 carried by the needle-bar and a pin 24 upon the needle-holder is guided alternately by two slots in a plate 15. The slots are united at their upper ends and when the needle reaches its highest position the pin 24 is engaged by the fork of a positively actuated lever 34 and is moved from one guide slot to the other. The needle is splined to a sleeve 13 toothed to gear with the looper mechanism. The racks 120, 117 are actuated by the usual feed-cam of the buttonhole - sewing machine. Specifications 18,195/02 and 9458/12 are referred to.