GB1398419A - Method of manufacturing a latch needle - Google Patents

Abstract

1398419 Making latch needles; forging; extruding SINGER CO 3 Oct 1972 [26 May 1972] 45448/72 Headings B3A B3H and B3P [Also in Divisions D1] A method of making a latch needle comprises; locating a needle blank in a die 12, pressing a punch 20 into the blank to form the exterior surface of the needle and to form a longitudinal recess in the blank, inserting a preformed latch member 54 in the recess and fastening the latch member in the recess. The punch 20 forms latch seats (34), (36) at either end of the recess, Fig. 4 (not shown), and the punch leading end 24 contours the bottom 38 of the recess. An alternative form of punch (42), Fig. 3a (not shown), is provided with a leading end portion (50) which pierces the bottom of the recess and enters a clearance (44) in a die (40), thereby punching a slot (52) in the needle. The slot may be punched in a separate operation after forming the recess. The latch members 54 are stamped from a strip 55 and may be formed with trunnions 62, 64 which are subsequently hardened. The latch is placed in the recess and walls 30, 32 of the recess are pressed against the trunnions, which form bearing seats for pivoting movement. Alternatively the latch may be secured by upsetting the recess wall into a hole in the latch or by a rivet.