Nonresetable thermally actuated switch

Abstract

A thermal limiter construction having a generally cylindrical housing or casing provided with an oppositely extending pair of conductor leads, one of which is insulated from the casing and the other is conductive with the casing. In the closed position, a contact engages the end of the conductor which insulated with the case. The contact has a flange member engaging the inner wall of the casing. A trip spring extends between the contact and the insulated casing end. A fusable pellet is provided in the lower end of the casing. An elastomeric member is interposed between the pellet and a contact surface and when deformed radially urges the contact flange members into tight engagement with the interior casing walls in the closed position. Upon collapse of the pellet when a pre-determined temperature is reached, the elastomeric member is allowed to return to a non-deformed condition permitting the trip spring to move the contact out of engagement with the end of the conductor interrupting conductivity across the device. In an alternate embodiment of the present invention, the fusable pellet is housed within a contact element having two opposed tabs engaging a conductor. Upon collapse of the pellet, axial support for the contact is removed and the contact is urged upwardly by a compression spring deforming the tabs around and out of contact with the conductor.

Dependencies are inferred from the claim text.