GB737721A - Improvements in rotary hook assemblies for lockstitch sewing machines - Google Patents

Abstract

737,721. Sewing-machines. UNION SPECIAL MACHINE CO. June 17, 1953 [June 18, 1952], No. 16677/53. Class 112. Lock-stitching by rotary hooks.-In order to prevent the bobbin-thread, when it becomes slack in certain circumstances, from drooping over the flange 47, Fig. 2, of the bobbin-case carrier (which contains the notch 48 for engagement by the rotation-preventing finger) this flange is provided with an extension or a member lying close to the path of the loop-seizing beak 24 of the hook. In the form shown in Fig. 2 this guard is constituted by a circumferential lip 57; in a modification, a guard of bent wire fixed to the inner face of the flange 47 takes the place of the lip 57. Additional guiding of the bobbin-thread may be provided by a self threading eyelet member 53, Fig. 9, fixed on a recessed portion 76 of the bobbin-case and fitting in a recess in the base of the flange 47 of the bobbin-case carrier. The rotation-preventing lug 49 in Fig. 2 is mounted on the finger 50 by a short piece of spring wire, to facilitate passage of the thread between the lug and the notch 48. The bobbincase, Fig. 9, has a central tubular pin on which the bobbin is carried and which fits over a pin in the bobbin-case carrier; it is secured on the latter pin by a sliding latch 65 operated by a pivoted lever 67, of which the end is arranged to enter a notch in the carrier to prevent rotation of the bobbin-case therein. Specifications 408,466 and 676,955 are referred to.