GB359769A - Improvements in and relating to sewing machines - Google Patents

Abstract

359,769. Sewing-machines. HUGHES, R. M., 72, Cannon Street, London.-(International Button Hole Sewing Machine Co. ; 502, Harrison Avenue, Boston, U.S.A.) Nov. 28, 1930, No. 35864. [Class 112.] Needles, vibrating laterally.-The thread tension of a laterally vibrating sewing-machine is released by means controlled by the needle-jogging mechanism when the machine comes to rest, and is restored when the machine is started. The invention is designed to obviate the skipping of first stitches in, for instance, buttonhole sewing-machines. The frame 1 is provided with an overhanging arm 4 in which is mounted a needle bar 5 reciprocating in a frame 47 which receives jigging motion from the cam on the shaft by the link 46 and arm 43. The arm 43 has a pin or follower engaging a groove in the cam, the arm 43 making one complete vibration to every two rotations of the shaft. The amplitude of the swing is varied by adjusting the link 46 and arm 43. The work clamps 3, with their associated thread gripper 13 and cutter 14, are actuated at the proper time by a cam 15, loosely mounted on the shaft 16 and clutched thereto at the correct time. Threads, controlling otherwise than in stitch-forming. -The needle thread tension device 11 comprises friction discs 21, 22 mounted on a stud 23. The disc 22 is engaged by another disc 61 acted on by a spring 24, the tension of which is regulated by the nut 25. When the machine comes to rest at the end of a stitching cycle, an extension 48 on the arm 43 engages the arm 49 of the latch 37 and releases the catch 39 on the rod 28, which is actuated by its spring 30 to push a plunger 27 in the stud 23, to separate the tension discs 21, 22. The rod is reset by the bell-crank lever 35 engaging the cam 67 on the shaft 16, this cam being normally idle and clutched to the shaft 16 at the same time as the cam 15.