Thermostatic switch and bimetallic disc assembly therefor

Abstract

A bimetallic disc assembly for a bimetallic disc-actuated thermostatic switch includes a disc retainer, a bimetallic disc received in assembled position on the disc retainer and a metallic retainer cap for retaining the disc in assembled position on the disc retainer and for securing the assembly to the body portion of the thermostatic switch. The disc retainer is adapted to minimize heat flow from the metallic cap to the disc retainer by minimizing the areas of contact between the disc retainer and the cap. The disc retainer is integrally formed from a ceramic material and it includes a central hub having an axial bore extending therethrough, a circular flange extending radially outwardly from the hub, a circular shoulder extending upwardly from the flange, and a peripheral rim extending upwardly from the shoulder. The peripheral rim includes a horizontal edge with a plurality of circumferentially spaced projections or bumps which extend upwardly therefrom. The metal cap is received on the disc retainer and rests upon the projections or bumps which effectively reduce the contact area between the cap and the retainer and thereby minimize the transfer of heat from the cap to the disc retainer. By reducing the heat transfer from the cap to the retainer, heat is more easily transferred from the metallic cap to the bimetallic disc, thereby improving response time.