Sealed case hold open thermostat

Abstract

A thermostat includes a case, including an exterior, that is made of conductive material. A cover plate is made of a conductive material. The cover plate is connected to the case to define a sealed interior. The cover plate has a contact projecting into the sealed interior. The contact is fixed with respect to the case and has an interior contact position. An insulator sheet is disposed between the case and the cover plate. A blade is disposed in the sealed interior. A second end of the blade moves between a first position where it abuts the contact position of the contact and a second position where it is spaced from the interior contact position of the contact. A resistor is mounted on a first end of the blade. The resistor is disposed between the cover plate and the blade in the sealed interior of the case. The resistor has a first side facing and abutting the cover plate, and a second side facing and abutting the blade so that the resistor is electrically connected between the cover plate and the blade. The resistor has a sufficient resistance so that when the second end of the blade moves from the first position to the second position a sufficient amount of heat is generated by the current flowing through the resistor to maintain the second end of the blade in the second position until a load current applied to the cover plate and the blade is removed.