Apparatus for casehardening a toothed arcuate member

Claim 1

Apparatus for surface-hardening an arcuate member having a first tooth and a second tooth, each tooth having opposed flanks and a root section which define a valley, said apparatus having: a. supporting means for supporting said arcuate member and having positioning means for fixedly locating said valley; b. casehardening means mounted in registry with said valley for casehardening said flanks and said root section; c. drive means connected to one of said supporting means and said casehardening means to cause relative movement between said valley and said casehardening means so that said casehardening means passes through said valley; 1. said casehardening means having: a. preheating means generally contoured to said valley to preheat a moving preheat area on said flanks and said root section; b. heating means adjacent said preheating means and generally contoured to said valley to then raise the temperature of a portion of said moving preheated area above the hardening temperature of said arcuate member without burning said portion of said moving preheat area tO form a heat hardened portion, said heating means defining with said root section a spacing d1 and with the top of said opposed flanks a spacing of d2, said spacing d1 having about one-third of said spacing d2 to balance the heating of said root section with the heating of said flanks; and c. quenching means adjacent said heating means, generally contoured to said valley and connected to a fluid source for quenching and casehardening another portion of heat hardened portion to form a casehardened portion and d. said preheating means, said heating means and said quenching means being sequentially moved relative to said valley.