Therm-O-Disc, Incorporated

Bernard S Deubel

Donald J Schmitt

A bimetal snap disc thermostat is disclosed in which a steel disc cup is provided for strength and/or environmental resistant properties. Positioned within the disc cup is a disc seat formed of aluminum. A bimetal snap disc is positioned in the disc seat and operates the thermostat switch through an axially movable bumper. A ring of rubber like foam material is positioned between the body assembly and the disc on the side of the disc remote from the disc seat. The aluminum disc seat reduces temperature calibration drift of the disc during the cycling of the disc which occurs during the use of the thermostat. The foam ring also tends to reduce bouncing and thereby tends to reduce temperature calibration drift. Also the ring functions to insure that the disc remains properly seated in its aluminum disc seat.

Bimetal snap disc thermostat arranged to reduce temperature calibration

A method of manufacturing sealed thermostats or the like is disclosed in which male and female members are assembled with an interference fit to produce a seal which is maintained through a predetermined operating temperature range. The minimum interference during assembly is selected so that such minimum interference is greater than the difference in the temperature during assembly and the most adverse seal temperature to be encountered within the temperature range, times the difference in coefficients of thermal expansion and contraction between the members times the linear dimension of the seal. In addition, the two members are selected so that the maximum total elastic deformation is greater than the difference in coefficient of thermal expansion and contraction times the difference between the maximum and minimum temperatures within the temperature range times the linear dimension. Preferably, the interference is selected so that the female member is stressed beyond its elastic limit, at least when the device is cycled throughout the temperature range to produce a mechanical interlocking of the two parts. The assembly of the device may also be arranged to provide calibration and/or gauging of the device.

Method of manufacturing sealed thermostats

A thermal fuse is disclosed in which a non-resettable bimetal snap disc operates with snap action to open the switch. The body assembly is provided by a unitary cup shaped molded body and a metallic disc cup which cooperate to enclose the switch cavity. The terminal and switch contact means are mounted on lateral projections and extend through adjacent openings into the switch cavity. A bumper extends between the disc and the movable contact to operate the switch in response to snap movement of the disc. The bumper is guided in opposed channels formed in the side of the body so that it is not necessary to provide an apertured wall or shield between the disc and the switch. Means are provided to allow resetting of the device after test operation during manufacture, but such mans are not available for user resetting of the device.

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Mansfield, OH, United States of America

Bernard S Deubel