Thermostat construction

Abstract

A thermostatic switch construction including a housing having a switch arm mounted for movement inside. A bi-metallic snap disk is mounted in the housing and movable in response to temperature change with snap action between two positions of stability. A switch arm actuating plunger is slidably mounted in the housing with its lower end adapted for contact by and snap movement by the bi-metallic snap disk. A creep gap assembly is provided which includes a creep gap screw threadably mounted in the switch arm opposite the upper end of the plunger. Axes of the plunger and the gap set screw are in alignment. The creep space between the lower end of the set screw and the upper end of the plunger is adjustable by rotation of the set screw. A temperature setting adjustment is provided which includes a spring member mounted in the housing with one end of the spring member in direct contact with the bi-metallic snap disk to thereby exert pressure on the disk. An adjustment screw is threadably mounted in the housing with its end in contact with the spring member. The adjustment screw is operable when rotated to adjust the degree of pressure applied to the bi-metallic disk by the spring member. In the double throw embodiment of the invention, a first switch contact is mounted on a flexible support member and the second contact is mounted on the switch arm. The gap between the double throw contacts is adjustable by means of an adjustable screw member threaded into a stationary support opposite the first contact.