Workpiece holder jig for hardening plant - where bore of spider hubs has axial grooves through which quenching liq. can flow to minimise thermal shock

摘要

The jig consists of an axial rod employed to hold a vertical row of carrier arms or spiders. Each spider consists of a central hub with arms arranged like the points of a star. In the bore of the hub is a circular row of axial grooves; and the base of each groove is semicircular in shape. The axial rod is pref. provided with at least one axial rib with a semicircular tip entering a groove in the bore of the spider hub. The rib prevents the spiders from rotating on the axial rod. When the jig is immersed in a quenching liq., the latter can flow through the grooves so all parts of the jig are cooled uniformly and thermal stresses are reduced. The result is that the working life of the jig is increased, as the hubs are less inclined to fracture.