Temperature sensor
View Patent ↗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.
1. A temperature sensor for a radiant heating element, comprising:
a switch having a housing and at least one contact spring which carries a contact and is implemented as a snap spring;
a first expansion element connected to the housing of the switch;
a second expansion element having a thermal expansion coefficient which is different from a thermal expansion coefficient of the first expansion element and being permanently connected to the first expansion element in a region of a free end of the second expansion element; and
a spring acting on the second expansion element in an axial direction thereof, wherein the second expansion element acts upon the contact spring from one side, and the spring acts upon the contact spring from another side through intervention of a spring-loaded support,
wherein the contact spring is pre-tensioned between the second expansion element and the support, when the temperature sensor is in a cold state, and
wherein the support and the second expansion element interact with the contact spring such that a mechanical strain on the contact spring decreases with an increase in temperature.
2. The temperature sensor of claim 1 , wherein the first expansion element is a tube.
3. The temperature sensor of claim 1 , wherein the second expansion element is a rod.
4. The temperature sensor of claim 1 , wherein the switch includes a buttress fixed to the housing, said spring being supported on the buttress and acting on the support via a plate spring.
5. The temperature sensor of claim 1 , wherein the switch includes a spring plate detachably secured to the housing, said spring being supported on the spring plate and acting on the support via the spring plate.
6. The temperature sensor of claim 1 , and further comprising a second said contact spring, wherein the second contact spring is controlled via a plunger which rests against the support at a side facing away from the second expansion element which is guided in the first expansion element, said plunger extending through the spring and connected to a sleeve which interacts with the second contact spring.
7. The temperature sensor of claim 6 , and further comprising an adjustment spring supported on the plunger and supported on a shoulder of the sleeve.
8. The temperature sensor of claim 6 , wherein at least one member selected from the group consisting of support and plunger is made of electrically non-conductive material.
9. The temperature sensor of claim 8 , wherein the member is made of ceramic.
10. The temperature sensor of claim 6 , wherein the contact spring has a linear support and is constructed in an area between the second expansion element and the support in the form of a double-wave shape.
11. The temperature sensor of claim 6 , wherein the contact spring has a linear support and is constructed in a section between the second expansion element and the support in the form of an open wave having a wave bow.
12. The temperature sensor of claim 11 , and further comprising an additional filled metal rod in a region of the wave bow for protecting the wave bow from deformation.
13. The temperature sensor of claim 1 , wherein the contact spring has a punctual support is provided in a section between the second expansion element and the support with embossed pressure points.
14. The temperature sensor of claim 1 , wherein the contact spring has a punctual support is provided in a section between the second expansion element and the support with an embedded sphere.