Temp. relay for hydraulic systems - has expansion capsule actuating profiled leaf spring contact to provide snap action effect

摘要

A temp.-activated relay has an expansion capsule positioned between a regulating pinion one side and a pivoted actuator plate on the other side. The plate carries an actuator pin and is biased by a leaf spring. The expansion capsule is connected to a capillary tube coupled to a temp. sensing probe. The end of the actuator pin lies against a cantilevered snap-action leaf-spring with an electrical contact at the free end. A centre section of the spring provides the snap action effect. Located on either side of the moving contact is a pair of fixed contacts. Once the set temp. is reached the spring contact switches to achieve a stable position.