Patent GB-550488-A (GB)
Title: Improvements in or relating to means and method for making socketed articles
IPC: B21K1/44
Filed: 1941-07-03
Abstract: 550,488. Forging socketed screw blanks, rivets &c. WILCOX, R. L., and WATERBURY FARREL FOUNDRY & MACHINE CO. July 3, 1941, No. 8385. [Classes 83 (ii) and 83 (iv)] In the forging of socketed articles such as screw blanks and hollow rivets a blank is forced over a socketing punch whilst held coaxial with the dies at each end but being free to expand in the middle. The socketing punch then forces the blank back through the die completing the socket by an extruding operation as the blank is returned to its original diameter. In the production of grub screw blanks a stock rod 25 is fed through a cut off die 22 mounted with a backing up die 24 in a holder 12 secured by a screw end wedge 13. The holder also mounts upsetting dies 26 and 84. A stop arm 27 rotatably mounted at 28 controls the length fed through the opening 37 in a combined transfer and cut off slide 36. A header slide 11 with a laterally shiftable gate or punch holder carries punches 18, 19 and a stripper 21. The slide 36 carries the blank opposite the die 26 and the punch 18 forces it into the cavity, squaring the rear end, bevelling the forward end at 30, and producing a central depression by the coned end 35 of the punch and knock-out pin 34. The slide 36 having returned to its initial position, the blank now of the form shown in Fig. 6 is ejected into a hole 40 in an extension member secured at 39 to the slide where it is held by a spring pin 40. A spring pressed block 31 ensures a prompt initial withdrawal of the pin 34. The extension may be integral with the slide. On the next stroke the punch 19 transfers the blank into the die 84 mounted in a shouldered carrier 51 itself retained in the die holder by a shouldered sleeve 106. The blank is advanced till the depression in it centres in the coned end of the socketing punch 56 supported by a spring plunger 86. Further advance of the blank seats the chamfered end in the bevelled mouth of the die 48 which separates from the die 84 as permitted by the backing spring 49. The forward end of the die 48 is reduced for guiding in the countersunk end of the die carrier 51. Projections 59 one on each side of the punch 19 engage the carrier 51 forcing the die 84 back. Meanwhile the end of the spring plunger 86 has been arrested by contact with the button 90 and the punch enters the blank causing it to bulge in the space between the two dies and in the bevelled mouth thereof. The spring 49 maintains the dies in contact with the blank as the latter shortens. On the return stroke the ejector-rod 92 advances and the punch forces the blank through the die 84 into the stripper 21. This comprises bevel closed jaws 62 seated by a spring 66. The front ends of the jaws have lips that close behind the blank as it is forced between them. Light springs let into the jaws separate them as they are forced back. When the ejector rod returns, the spring 49 acting through the last 50 returns the punch, shifting it from the blank. Succeeding blanks push the ejected blank through the opening 68 to fall into a receptacle. Should the end of the socketing punch break off, the blank (containing the broken end) is apt to pass right through the die 84 and to get jammed between the face of the die and stripper causing damage. To prevent this the unit from the die is resocketed by a flexible member 81. Lubricant supplied at 72 under the control of a valve 73 passes at 71 to a port leading to passages 79, 70 delivering the oil to the dies and punch. Modified dies are illustrated and described for producing rivets. hollowed out at the shank end, this end being square or bevelled either internally or externally. The die holder 12 is recessed at 76 to accommodate the punches when the gate is raised to bring the stripper into operative position.