Johnson Service Company

Hamilton Standard Controls, Inc.

Robert A Van Fossen

Donald E DeWitt

Jesse H Turner

Scott L Spence

A float switch for sensing a liquid level and switching between 'on' and 'off' states in response to the same. Overall, the device is carried within a hollow housing, with its movement restrained by the tethering action of a power cord. 'Snap action' switching is achieved by the interaction between an actuator having camming surfaces formed on its exterior, and a spring-loaded switch mechanism. The switch mechanism includes a thin, flexible E-shaped snap member, having two legs bowed to form a leaf spring and having a bearing point located on the central leg. The actuator is carried in a tube within the housing and the switch mechanism is positioned adjacent the actuator's path of travel, so that a camming surface of the actuator can make contact with the bearing point. As the water level rises, an increasing proportion of the actuator's weight is carried by the bearing point, until the vertical component of the actuator weight exceeds the spring resistance of the snap member. The characteristic operation of the spring is such that it yields only suddenly and completely rather than gradually, providing a desirable snap action operation.

Float switch with snap action member

A flow switch adapted to be attached to a pipe is designed to trip a switch at a preset flow rate. The switch employs a bending metal blade which deflects in the flow stream to move a magnet attached to the downstream side of the blade relative to a reed switch or Hall-effect switch. The switching device is preferably mounted in a slot on a printed circuit board to enable selection of a range of available trip points.

Magnetically actuated proximity flow switch

A differential pressure sensor indicating a housing forming a high pressure chamber, a nozzle mounted on the housing at one end of the chamber, a diaphragm mounted in the chamber to form a low pressure chamber in the nozzle, a spring retainer in the high pressure chamber, a spindle connected to the diaphragm, a tension spring connecting the spindle to the spring retainer, a circular magnet mounted on the spindle and a transducer mounted on the housing to sense the position of the magnet.

Differential pressure transducer

A compact linear operator is provided for a gas valve. The operator may be of modular form for operative combination with combination gas controls of existing design, as by threaded engagement with an existing threaded bore in the control. The operator is suited for directly controlling displacement of a valve or more typically, for controlling displacement of the seat for the regulating spring associated with a servo pressure regulating diaphragm/valve arrangement. The operator includes a controllably heated bimetallic actuator, and a plunger directly or indirectly driven linearly by deflection of the actuator. To enhance compactness of the operator, a displacement-amplifying lever is interposed between the actuator and the plunger. Stops are included for establishing 'high fire' and 'low fire' limits for the regulated gas pressure.

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Auburn, IN, United States of America

Robert A Van Fossen