Abstract: A control device has a nested stack of dished disc elements disposed in a cup beneath a diaphragm to move toward an inverted dished configuration with snap action to perform a control function or the like in response to occurrence of a predetermined pressure applied to the discs through the diaphragm. An annulus or bolster disposed between the rim of the cup and the diaphragm has an inner diameter nested in closely spaced relation to the domed, central portion of the dished element at the top of the stack normally cooperate with the stack of elements in supporting the diaphragm against pressure applied to the diaphragm. The annulus protects the diaphragm from being damaged by being pressed against peripheral portions of the disc elements when the discs move with snap action to their inverted dished configurations.

Abstract: An electric switch is shown which is responsive separately to two different conditions, i.e. temperature and pressure. The switch includes a temperature sensing disc and a pressure sensing disc both coupled through several alternate motion transfer arrangements to the movable electrical contact of the switch. Several structures are shown for mounting a switch on a surface so that the pressure sensing disc is exposed to fluid pressure and the temperature sensing disc is thermally coupled to the surface.