Patent GB-190404051-A (GB)
Title: Sewing Machines and Method of Fastening the Ends of Threads employed in Forming Groups of Stitches.
Inventor: FAIRWEATHER WALLACE
Filed: 1904-02-18
Granted: 1905-02-02
Abstract: 4051. Fairweather, W., [Singer Manufacturing Co.]. Feb. 18. Buttonattaching machines; buttonhole - sewing machines; lock-stitch shuttle sewing-machines ; knotted-stitch machines ; feed ; needles.-In machines for attaching buttons, sewing or barring buttonholes, &c., the threads are secured by two or more " fastening" or knotted stitches, and then automatically cut. The invention is described as applied to a button-attaching machine. The button is held on the material by a spring- closed work-clamp 51, Fig. 2, which is moved in two directions at right-angles by a cam-wheel 35. The motion parallel to the main shaft is transmitted by a slotted lever, pivoted on a bracket 40 and actuated by a groove on the inner surface of the cam. The lever engages a sliding block adjustably clamped to a pillar, integral with the work-clamp. The lateral motion is imparted to a plate 50, loosely connected to the work-clamp, by a cam-lever 39 through a slotted bell-crank lever and the adjustable rod 41. The final knotted stitches are produced by twisting the needle-thread loops before they are presented to the loopspreader. During their formation, the feed is inoperative, and the twisted stitches, following one another without any intervening material, produce a fast knot. The first twisted loop is caused by the previous relative movement of the needle and work, as indicated in Fig. 11, and, to ensure the twisting of the succeeding stitches, the needle is provided with a spiral groove 101 below the eye, which will retain the needle thread on the front side of the needle. Stopping, automatic.-The starting-lever 23 is pivoted at 21, and a spring tends to hold it in the stop position. It may be moved into the starting position, as shown, by a knee-lever 29, and is then retained by a detent lever 27 until the inner face of the cam-wheel acting on the latter releases it to stop the machine automatically. Thread-cutters; governing needle thread.-The thread-cutting knives 61, 62, Fig. 17, and the thread-end holder 97 are secured to a pinion 63, mounted on the underside of the shuttle-race cover, which gears with a rack attached to a long sliding rod 67, Fig. 2. The knives are rotated to engage the threads, preparatory to cutting, by the movement of the cam-lever 70, and a sudden movement for the cutting operation is derived through the cranked lever 74 from the lever 23, as it moves to stop the machine. The first movement brings the spring-pressed plunger 75, on the bell-crank lever 74, almost into registry with a slot in an extension 30 of the lever 23. Then as the lever 23 is tripped, a spring-plunger 25 engages a stop on the driving-shaft which gives to the lever a sudden lateral motion about the universal pivot 21, causing the plunger 75 to be engaged by the rod 30 and imparting through the lever 74 &c. the required sudden motion to the knives. During the thread-cutting operation, the needle thread is held by a lever plate 84, which is pivoted on the needle-bar and is caused to pinch the thread between it and the needle-bar by a cam-lever 90 acting upon a bar 87. Thread-end holders.-At the commencement of the operation, the thread ends are held by a tongue 97, Fig. 17, which presses on the underside of the work-plate. By the action of the cam-lever 70, it is moved across the needle-hole after the first stitch, and retains the thread ends during two or three succeeding stitches.