GB502152A - Process of and apparatus for effecting local hardening of mass-production articles - Google Patents

Abstract

502,152. Hardening metal articles. SCHAURTE, W. T., and KAUFMANN, K. Sept. 10, 1937, No. 24730. Convention date, Sept. 10, 1936. [Class 72] Local hardening of mass-produced articles, such as knife-blades, needle points, and the heads and points of bolts and set-screws is carried out by inserting the articles into pockets in heat-conducting blocks and feeding them in the blocks at selected intervals to a heating device and immediately thereafter, in one step, to a chilling device, both devices acting on the exposed surfaces of the articles. An automatic apparatus for carrying out the process comprises a drum 7 carrying a number of rows of blocks 4 having jackets 5 for the reception of the articles, which are shown as set-screws the upper portions of the heads of which are to be hardened. By means of a cam-operated ratchet gear the drum is rotated in a step-by-step manner to bring the pockets opposite to a feeding-device 11, from which the set-screws are fed into them, and thence successively past burners 12 and chilling devices 13. The burner flames and the chilling sprays strike the heads of the set-screws centrally, and the sprays splash over the edges of the heads and the faces of the blocks without entering the gaps between them. The heating may be performed electrically by induction or resistance heaters. In treating knives, the knives are held in heat-conducting blocks with only the blades projecting and the heating may be performed by clamping the blades between copper jaws and passing a current through them.