Patent GB-677936-A (GB)
Title: Improvements in or relating to method of making socketed articles such as screws, bolts, or the like
IPC: B21K1/46
Filed: 1950-04-20
Abstract: 677,936. Making bolts &c. NATIONAL MACHINERY CO. April 20, 1950 [May 3, 1949], No. 9719/50. Classes 83 (ii) and 83 (iv). Extruding; forging. - A method of producing a headed, socketed article comprises extruding a blank to form a shank of reduced section and an unworked head part, upsetting said head part to produce a shorter head part of greater crosssection and socketing said head part with a tool, while cold. A cylindrical metal blank is extruded into a die D<SP>1</SP> by a punch T<SP>1</SP> to form an extruded shank portion 7 and an unworked head 6, and is then ejected by a punch Kl. The blank is then placed in a die D<SP>2</SP> and headed with a tool T<SP>2</SP> to form a head having a conical portion 16, a cylindrical portion 17, another conical portion 18 and a rounded end portion 19. For the socketing the blank is placed in a die D<SP>3</SP>. A reciprocating header slide H has a tool-supporting sleeve 20 apertured at 21 to receive a sliding sleeve S and its mounting sleeve 22. A punch assembly P and a stripping sleeve 32 are carried within the sleeve S and retained therein by a member 25. A pair of plunger blocks 28 and 29 are assembled over the head of the pin P which has a hexagonal socketing portion 31. The stripping sleeve 32 has a rear flange 34 against which bear pins 35 attached to a plunger 37 having a rounded end 39 which engages a lever member C mounted in the header slide by pivot 41. Lever C is operated by a push-rod 51 actuated by a lever V pivoted to a support on the header slide and operated by a cam follower roller 58 which engages a cam 59. In operation as the header slide advances the punch forces the blank into the die D3, the sleeve S is advanced by means of compressed air so that it surrounds the headed portion of the blank and contacts the die D3, and the punch is forced into the blank by engagement of the plunger block 28 with the backing plug 25. As the header slide retracts the stripping sleeve 32 remains stationary relative to the die and prevents the blank from being withdrawn from the die by the punch. The socketed blank portion is then drawn to a uniform cross-section by the sleeve S which is withdrawn when a flange 24 on the sleeve engages the rear of the mounting sleeve 22. The punch is withdrawn from the blank when a shoulder 33a on the sleeve S engages the plunger blocks 28 and 29. The blank is stripped from the die D<SP>3</SP> by a knock-out pin K<SP>3</SP>. The die may be recessed as at 70 in the die D<SP>4</SP> (Fig. 13) so that part of the head is formed in the die itself. The recess 70 may be tapered or undercut to assist in gripping the blank. In a modification, the stripping sleeve 94, Fig. 16, has a rear flange 95 and is urged towards its outward position by spring- pressed plungers 96 engaging the flange 95. To retain the sleeve against the blank a pair of spring-loaded cams 100 are mounted.in recesses in a block 86. The header slide H<SP>1</SP> is reciprocated by a rod 112 connected to a crank-shaft 110. A stripping plunger 91 engages a spring- loaded cam follower F which engages a cam C<SP>1</SP> on the shaft 110. The cam follower F is controlled on the retract stroke of the header slide by a roller 127 which engages a surface 128 on the header slide. In operation, as the header slide completes its forward stroke, block 89 engages plunger support blocks 87 and 86 and forces the punch P<SP>1</SP> into the blank, the sleeve S already being forced over the head of the blank by compressed air. As the slide retracts the sleeve S<SP>1</SP> is stripped from the blank but the cam C<SP>1</SP> has maintained the plunger 91 and the punch P<SP>1</SP> stationary so that the blank is held in the die. The cams 100 then engage an inner wall of the sleeve S<SP>1</SP> and hold the blank in the die while stripping the punch from the blank which is finally ejected from the die by the knock-out plunger K<SP>4</SP>. Specification 677,937 is referred to.