Heat treatment jig for holding workpieces - where jig is assembled from three sections, each free to expand and contract

摘要

The jig is immersed in a salt bath or a pot- or shaft-furnace, and is then dipped in oil or water to quench the work-pieces; and the jig is a spider assembled from three straight sections which form six arms spaced at 60 degrees intervals round a central hub. Each of the three sections has a central boss contg. a hole provided with cam profiles; the cams lock into grooves on a profiled with cam profiles; the three holes to make the six-armed spider. The profiled rod locks all three sections together. The jig is rigid, but has a low wt., and each of the three sections is free to expand or contract independently, so distortion and/or cracking of the jig is avoided. The jig thus has a long working life, and is easy to dismantle and re-assemble when =1 of the sections must finally be repaired or replaced.