Thermally responsive switch

Abstract

A thermal motor protector includes a cylindrical metal housing having an open end and a bimetal disposed in the housing so that its one side is opposite to an housing inner bottom. The bimetal has a shallow dish-shaped portion so that it inverts its curvature at a first temperature with a snap action and re-inverts its curvature at a second temperature. A support is disposed in the housing opposite to the other side of the bimetal and has a preselected elasticity. A fixed contact member is disposed in the housing, and a movable contact member is held by a stationary member in the housing so as to be movable relative to the fixed contact member. A pressure strip is formed separately from or integrally with the movable contact member so as to project from and to be moved with it, the pressure strip having a distal end in contact with the support so that a force is applied to the bimetal at a predetermined pressure. A header plate is secured to the housing so as to hermetically close the open end of the housing, the header plate having at least one opening, and a terminal pin is hermetically held in the header plate opening with an electrically insulating material charged between them.