GB727340A - Improvements in sewing machines - Google Patents

Abstract

727,340. Sewing-machines. UNITED STATES BLIND STITCH MACHINE CORPORATION. Dec. 16, 1952, No. 31885/52. Class 112. Blind-stitching machines. In a sewing-machine having a pivoted work support and a needle moving in a path transverse to a plane which is perpendicular to the work support and contains the feed path, main and auxiliary bight-forming members are turnably, mounted below the work support so that each may be oscillated into and but of a position in which it projects through the aperture in the work support to form a bight in the work, automatic operating means being provided to oscillate the main member and means connecting the two members in such a way that the auxiliary member is oscillated reversely to the main member. In the machine shown the work support 27, Fig. 6, is in the form of an arm pivoted to the frame F at 28p and extending to one side of the frame so that its end lies under the needle-carrying arm of the frame; the support 27 is urged by a tension spring against the end of a rod 29 which is adjustable by means of a lever 32 and finger-knob 34. ' The main bight-forming member 15, Fig. 13, is mounted releasably and adjustably on a shaft 17 which is carried in bearings in the support 27 and is oscillated from the main shaft 18 through gears 20, eccentric 22 and pitman 23. The auxiliary bight-forming member 14 is fixed to the end of a spindle 16 which is carried by arms 36, Fig. 9, of a yoke mounted on a shaft 35 supported by the frame F; the member 14, shown dotted in Fig. 9, has a notch 27<SP>1</SP> which engages a pin 28 carried by the main member 15, so that oscillation of the latter in one direction causes movement of the member 14 in the opposite direction, and the two members are projected into engagement with the work alternately, one at each needle stroke. An extension 38 of one of the arms of the yoke 36 is connected by a link 39 to an adjusting screw 42 which engages a member 43, with finger-knob 49, rotatably mounted in the work-support 27, to adjust the height of the member 14 relatively to the frame F; a flange of the knob 49 has teeth on its underside for engagement by a spring-pressed ball detent 52. Adjustment of the work-support 27 about its pivot 28p causes an opposite movement of the yoke 36 and member 14, since the shaft 35 is fixed, and also varies its amplitude of oscillation by varying the distance of the pin 28 from the spindle 16, but the member 15 remains in the same position relatively to the work-support. Stitches and stitched seams. Since the bightforming members 14, 15 operate alternately, stitches are made alternately in the fold of the upper work-piece 12, as shown in Fig. 13, and in the lower work-piece 10 at a short distance from the fold. A chain-stitch seam is preferred, but a lock-stitch or other form of seam may be used.