GB772570A - Needle vibration controlling mechanisms for zigzag sewing machines - Google Patents

Abstract

772,570. Sewing-machines. SINGER MANUFACTURING CO. May 20, 1955 [May 26, 1954], No. 14565/55. Class 112. Means are provided for locating the needlebar frame of a zig-zag sewing-machine in a desired lateral position when the pattern-cam vibrating it is removed, for straight stitching. In the machine shown, the needle-bar frame is oscillated by a pitman 25 pivoted to a slide 55 which is reciprocated in an angularly-adjustable guide 57 by a pattern cam 27 through a rock-shaft 38, arm 50 and link 52; the cam 27 is held by a finger-nut on the end of a shaft 29 driven by worm-gear from the needle-bar shaft, and can thus be readily removed for replacement by another cam giving a different stitching pattern. The rock-shaft 38 has a cam-follower arm 40, a collar 45 to which a brassing spring 42 is attached, and an arm 46 carrying an adjustable stop-screw which engages an abutment on the machine frame to determine the position of the cam follower, and therefore of the needle-bar frame, when the cam is removed; the screw may be used to lift the follower from the cam. The slide 55 is cylindrical, and the guide 57 is fixed by a screw to an arm on a hollow shaft 60 with a finger lever 63 working over an indicating scale and locked in the required position by a screw passing through a slot in the lever. A spindle 70 inside the shaft 60, with a finger lever 76, carries an eccentric pin engaging a transverse slot in a member 73 slidably mounted' between the guide 57 and its supporting arm, and the member 73 has a pin 75 projecting into the guide 57 ; in its lowest position this pin is outside the range of movement of the slide 55, but in actuation of the lever 76 it can be moved to shift the slide along the guide to shift the needle-bar frame laterally and to lift the cam-follower from the cam. The lever 76 has a spring. plunger which engages recesses in the lever 63 to hold the former lever in positions .which will produce straight stitching respectively in the extreme lateral positions and the middle position of the needle-bar frame.