Abstract: A magnetically latching switch assembly adapted for use with a motor including first and second serially connected coils wound around a frame to generate oppositely directed magnetic flux through the frame. The coils are arranged so that for the normal run current of the motor, the net magnetic flux is sufficient to magnetically latch the switch against the restoring force of a spring. When the motor is stalled, the increased current is sensed and a portion of the current is diverted from one of the coils to reduce the net magnetic flux and terminate the latching effect. Current sensing and diverting is accomplished by a diode connected across the one coil.

Abstract: An oil level sensor assembly adapted for installation in an automobile engine crankcase at the level corresponding to "low oil". The sensor assembly utilizes the principle that air is expandable whereas oil is not. Accordingly, when it is desired to sense the oil level, a predetermined amount of fluid is trapped within a chamber sealed by a diaphragm. If the oil level is adequate, then the sensor will be below the oil level and the trapped fluid will be oil. However, if the oil level is low, the trapped fluid will be air. After the fluid is trapped, a spring operating on the diaphragm attempts to expand the chamber. If the admitted fluid is air, the chamber can be expanded and a switch contact will be made, to provide an indication of low oil level. On the other hand, if the chamber is filled with oil, the chamber will not expand and the switch contact will not be made.

Abstract: A momentary contact rocker switch utilizes a pair of torsion springs as movable switch contacts, with fixed terminal posts being used as fixed contacts. The terminal posts are grooved in the region of contact with the torsion spring to provide a wiping action. This wiping action, along with the high electrical contact forces provided by the torsion spring, eliminates the need for silver contacts.

Abstract: A flow rate sensor includes a diaphragm operated switch coupled to a Venturi in a flow conduit. The apparatus includes a housing having a diaphragm defining a chamber. The chamber has a first port connected to the Venturi and a second vent port. A valve connected between the first port and the diaphragm is spring loaded so that the first port is normally open. In the absence of fluid flow, the Venturi pressure is zero under the diaphragm and the diaphragm is at rest in an up position so that the valve is open. With fluid flow through the Venturi, vacuum will build under the diaphragm so that the diaphragm will travel down until the valve closes the first port. With the valve closed, pressure under the diaphragm will increase due to flow through the vent port and the diaphragm will move up. The valve will remain closed until the diaphragm up stroke is equal to the valve stem lost motion.