Abstract: A smoke detector with a visual battery missing indicator and a removable cover includes first and second locking prongs molded in the detector and directed toward the cover. A battery is positionable between the first and second locking prongs deflecting same from a non-locking position to a locking position. In the locking position, free ends of the prongs can engage the cover, locking same to the detector. In the non-locking position, the prongs are not effective to engage the cover. If the detector is mounted on a ceiling, the non-engaged cover will not remain closed. In an alternate embodiment usable with a bracket mounted detector, a depressible blocking member is located adjacent a region where the detector is normally coupled to a portion of the bracket. In the presence of a battery this member is retracted, enabling the unit to be attached to the bracket. In the absence of a battery, this member is extended and the detector cannot be attached to the bracket.

Abstract: A rapid response thermal switch for isolated load control includes a bimetallic switch electrically connected to a controller and operatively connected to a switch follower which controls the operation of a second switch electrically connected to a load so that the load is electrically isolated from the controller. While energization of the bimetallic switch by the controller causes the bimetallic switch to move away from its switch follower, the switch follower is biased to follow the bimetallic switch. The initial movement of the switch follower allows the load current controlling switch to close, energizing the load. The bimetallic element, heated by the controller currents flexes to cycle itself on and off while maintaining the load controlling switch in the closed position. When the bimetallic element sufficiently cools after deenergization, it returns the bimetallic switch to its closed position.

Abstract: An infinite switch for controlling the temperature of a stove heating element is provided with a visual indicator energized when the heating element is energized. The switch has terminals connected to an electrical power source and includes a housing, a cover with a central aperture, and a rotatable, hollow spindle extending through the aperture and into the housing. A cam mounted on the spindle interacts with two sets of switch contact elements. One set of contact elements is movable by the cam from an open to a closed position thereby connecting the power source with the second set of contact elements. The second set of switch contact elements are adjusted by the cam and are operated by a thermomotive element in heat transfer relation with a thermal heating device. The thermomotive element cycles the second set of contacts between open and closed positions alternately to energize and deenergize the heating element. The proportion of on time during each cycle is determined by the position of the cam.