Patent GB-190918245-A (GB)
Title: Improvements in Sewing Machines.
Inventor: FAIRWEATHER WALLACE
IPC: D05B3/10
Filed: 1909-08-07
Granted: 1910-03-10
Abstract: 18,245. Fairweather, W., [Singer Manufacturing Co.]. Aug. 7. Button-attaching machines; buttonhole-sewing machines; stopping, automatic. - In machines for producing groups of stitches, the work-clamp is closed by the straightenir g of a toggle joint either by hand or by part of the stop-gear in starting the machine. The joint is held straight until the close of the stopping-movement of the stop-gear, and then is bent by a part of the gear to permit the clamp to open. At the completion of a group of stitches, the starting-treadle is operatively disconnected to ensure the release of the stop-gear. The improvements are shown applied to a buttonattaching machine such as described in Specification 4051/04. The upper member of the travelling work-clamp is connected by a ballended rod to the lever that opens and closes the clamp, which lever is mounted on a fixed pivot. The upper ball-end is held between the lever and a leaf-spring on the lever, which yields to enable the work-clamp to accommodate itself to work of different thicknesses. The workclamp is closed when toggle links 64, 67, between the rear end 56 of the opening- and closing- lever and a bracket 62 on the machine frame, are straightened; the straightened position being determined by a screw stop in an extension 67<Î> of the lower link 67, which abuts on to the link 64. The toggle may be straightened by a hand pull-rod 72 connected to an extension 68<Î> of the link 67, or by a pin 75 on a lever 76 linked to the stop-gear. The lever 21, which pushes the stop-lever 16, of usual construction, out of engagement with the cam 12 into starting position, is linked to the lever 76 by a rod 78, and both are operated when the rod 78 is depressed by the direct downward pull of the treadle rod 89, 90. The lever 21, however, is operated by contact with a nut 79, which is adjusted so as not to come into contact with it until, by the pin 75, the lever 76 has straightened the toggles 64, 67 and positively closed the work-clamp. A catch 22 holds the stop-lever during the stitching operation and, with it, holds the lever 76. At the completion of each group of stitches, when the catch 22 is tripped and the stop-lever 16 released, the levers 21, 76 are rotated and the locking-pin 75 is removed. Then, when the plunger 14 snaps into the recess 13, and the over-throw of the machine rotates the stop-lever in opposition to the usual spring-buffer, a finger 83 secured to the stoplever engages with a bevel on an extension 81 of the toggle-link 64, bending the joint and enabling a spring 59 to pull down the lever 56 and open the work - clamp. Normally, the treadle-rod 89 is effectively connected to the rod 78 by the link 85 which is held substantially in line with the rod 89 by a spring 96 to form a toggle strut. To prevent the stop-gear, when released by the catch 22, from being held out of operation by the treadle, a lever 101 is operated by the tripping-cam just prior to the operation of the catch 22, and, in engaging with an ear 86<Î> of the link 85, presses the link out of the vertical, so rendering the connexion with the treadle ineffective, as shown in Fig. 4. The thread - pulling finger 106, Fig. 6, is operated, not from the upper clamp member, but from an extension 108 of the lever that opens and closes the clamp, the movement of this lever being invariable.