GB736402A - Improvements in or relating to the manufacture of cutlery - Google Patents

Abstract

736,402. Making knife blades. BERNARD & SON, Ltd., M., MILLER, D., and CUTTS, D. K. June 23, 1953 [March 26, 1952], No. 7803/52. Classes 83 (2) and 83 (4). Knife blades are made by cutting flat steel stock into blanks each having a blade portion, a tang portion of reduced width and an intermediate portion affording metal for the bolster, hardening and grinding the blade portion into a tapered cross-section, electrically upsetting the bolster without drawing the temper of the blade, die shaping the bolster and tang and polishing the bolster. The blade portion may be mirror finished after hardening and grinding. The blade is gripped in a water-cooled device, and the bolster and tang portions are heated to forging temperature before die-forging. In the latter operation endwise pressure is applied to the end of the tang. Upsetting.-The bolster is upset in an electrical upsetting machine, Fig. 5, comprising two pairs of water-cooled jaws 32, 33 and 42, 43 connected across the secondary of a transformer and separated by a gap 15 into which the bolster is upset. The upper jaws, which are of copper, are operated by fluid-pressure rams 31, 41 respectively, whilst the lower jaws 33, 43, made of copper alloy, are mounted on vices 27, 37 respectively, slidably mounted in guideways on sub beds 22, 21. In operation the blade portion is firmly gripped by the jaws 32, 33, whilst the tang portion can slide through the jaws 42, 43, and the end of the tang portion abuts against a block 45 slidable on the vice 37. The latter is fixed on the bed 21 whilst the vice 27 is slidable thereon. Alternatively the tang portion is gripped by the jaws 32, 33 and the blade portion slides through the jaws 42, 43 and abuts against the block 45. During upsetting, the block 45 is moved to the left by a fluidpressure ram 48 acting through a strong spring 46, and pushes the intermediate portion of the blank into the gap 15 where it is upset to form the bolster. The vice 27 with the jaws 32, 33 are retracted slowly by a fluid pressure ram 35 to increase the gap 15 as more metal is upset therein. Inserts 52, 53, 62, 63, Fig. 6, of a hard conductive metal such as " Mallory metal," are mounted on the jaws, the lower inserts being grooved at 54, 64 respectively to receive the blade blank. Smaller inserts 55, 56, 65, 66 of hot die steel are fitted into the main inserts. The inserts 65, 66 have lips 67, 68 which project without engagement into hollows 57, 58 of the inserts 55, 56 at the beginning of the upsetting operation to provide support for the blank. Specification 692,042 is referred to.