GB755891A - Improvements in or relating to sewing machine - Google Patents

Abstract

755,891. Sewing-machines. GEGAUF AKT.- GES. BERNINA-NAHMASCHINENFABRIK, F. June 8, 1954 [June 18, 1953], No. 16808/54. Class 112. [Also in Group XXIV] Needles, shifting laterally.-Plain zig-zag stitching is produced positively at high speed and ornamental stitching is produced by cams, the two mechanisms being actuated by gears driven at different speeds and being selectively connected to the lever from which the needle shift is derived. In the machine shown, the needle-bar gate 12 is shifted about a vertical axis by a link 14 carrying a slide-block 19 in a guideway in an arcuate lever 17 fixed on a shaft 18, the block being adjustable along the guideway by known means engaging the forked end 15 of the link to vary the throw of the needle. Freely mounted on the shaft 18 are a forked lever 25 embracing a cam 22 driven from the needle-bar shaft 4 through spiral gears 20, and a forked lever 29 embracing a roller on the end . of a bell-crank 31, 33 which is actuated by cams 38 on a shaft 42 driven from the shaft 4 through worm gearing 39; both levers 25, 29 have notches N for selective engagement by a coupling element slidable parallel to the shaft 18 in a member fixed on that shaft, whereby either of the levers is connected to the shaft as desired for actuation of the lever 17. The cam follower 34 is slidably mounted in a horizontal slot in the upper end of the crank arm 33 so as to be movable into position to engage any one of a series of cams fixed on the shaft 42, and is shifted along this slot by a finger lever 35 mounted on a universal joint on the lower wall of the machine arm 2 so that it can swing across the arm along a scale 49 and can also swing in a plane parallel to the shaft 4 to disengage the follower from the cams and a detent 47 from a fixed notched locating bar 48. Movement of the lever 35 across the arm also actuates the coupling element by a forked arm on the lever pivot, so arranged that the element is in engagement with the lever 29 so long as the follower 34 is opposite any of the cams 38, but further movement of the lever 35 towards the front disengages the element from the lever 29 and engages it with 25. If desired the coupling element may be actuated by means separate from the cam-selecting lever 35; the gear 39 may, in a modification, be driven through the gears 20.