US Patent 7345572 Temperature sensor

A temperature sensor for a radiant heating element includes a first expansion element, e.g., a tube, connected to a housing of a switch, which is permanently connected to a second expansion element, e.g., a rod in the region of its free end. The two expansion elements have different thermal expansion coefficients, and the switch has at least one contact spring, which is pre-tensioned against a point and carries a contact. The contact spring is implemented as a snap spring. The first expansion element has a spring acting in its axial direction applied to it. To avoid rapid fatigue of the contact spring, the second expansion element acts on the contact spring on one side and the spring acting in the axial direction of the second expansion element acts on the contact spring on the other side, with the spring acting against the second expansion element via a support.