Abstract: The actuator piston has a generally cylindrical central projection about the exterior of which a similarly formed rolling diaphragm is closely fitted. The piston rod can turn freely, to avoid any twisting of the piston and diaphragm, and can also be axially withdrawn from its engagement with the piston. Return spring means extends into the diaphragm enclosed part of the piston.

Abstract: A thermal timer produces a timed duration output in response to a thermal input to a thermal storage device and a thermal energy leakage parameter from that storage device. The storage device preferably is a metal slug positioned in a silica aerogel insulative powder environment, and the thermal input is supplied by an electrically energized PTC heater. A thermostat output device monitors the temperature of the heater and the storage device to effect a distinguishable output, for example, by completing or opening an electrical circuit, in response to the temperature thereof. The thermal timer may be utilized in a range appliance or the like to effect a warning indication during cool down of that appliance.

Abstract: A partitioning sleeve is positioned in the main body of a thermal actuator to form a separate internal liquid reservoir from which fluid may be supplied to the actuator heater. The heater is part of a heater sub-assembly that is sealed in an opening formed in the main body of the actuator so that the coil-type electric resistance heater is accurately positioned for submersion in liquid in the variable volume chamber formed in the main body of the actuator. Moreover, the recycling or cool down time for the thermal actuator is reduced by thermal transfer between an appreciable contacting surface area of an extensible diaphragm that partly forms the actuator chamber and a guide cap that also supports and guides the diaphragm during its extension to enlarge the variable volume chamber.

Abstract: A partitioning sleeve is positioned in the main body of a thermal actuator to form a separate internal liquid reservoir from which fluid may be supplied to the actuator heater. The heater is part of a heater sub-assembly that is sealed in an opening formed in the main body of the actuator so that the coil-type electric resistance heater is accurately positioned for submersion in liquid in the variable volume chamber formed in the main body of the actuator. Moreover, the recycling or cool down time for the thermal actuator is reduced by thermal transfer between an appreciable contacting surface area of an extensible diaphragm that partly forms the actuator chamber and a guide cap that also supports and guides the diaphragm during its extension to enlarge the variable volume chamber.