THERMOSTAT AND METHOD

• US 20130057381A1
• Filed: 09/06/2011
• Published: 03/07/2013
• Est. Priority Date: 09/06/2011
• Status: Abandoned Application

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Kandhasamy, Senthilkumar Mettuppalayam
• Application Number:
  US13/226,340
• Publication Number:
  US 20130057381A1
• Time in Patent Office: Days
• US Class Current: 337/348
• CPC Class Codes: H01H 37/52 actuated due to deflection of bimetallic element
• CPC Class Codes: H01H 37/54 wherein the bimetallic element is inherently snap acting
• CPC Class Codes: H01H 37/5409 Bistable switches; Resetting means
• CPC Class Codes: H01H 37/5427 encapsulated in sealed miniaturised housing
• CPC Class Codes: H01H 37/70 Resetting means H01H37/5409 takes precedence
• CPC Class Codes: H01H 37/74 Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling

Abstract

The present disclosure relates to thermostats. In one illustrative embodiment, a thermostat includes a housing defining a cavity, an electrical contact, a temperature sensitive disc that is configured to transition from a first stable state to a second stable state at a first temperature, and a spring disc having a first stable state and a second stable state. During operation, the temperature sensitive disc may apply a force to the spring disc that causes the spring disc to transition from its first stable state to its second stable state when the temperature sensitive disc transition from its first stable state to its second stable state at the first temperature. The force required to move the spring disk from the first stable state to the second stable state may be less than the force required to move the spring disk from the second stable state to the first stable state.

Claims

1. A thermostat comprising:

a housing defining a cavity;

an electrical contact;

a temperature sensitive disc that is configured to transition from a first stable state to a second stable state at a first temperature;

a spring disc positioned adjacent to the temperature sensitive disc, the spring disc having a first stable state and a second stable state, wherein the temperature sensitive disc applies a force to the spring disc that causes the spring disc to transition from its first stable state to its second stable state when the temperature sensitive disc transition from its first stable state to its second stable state at the first temperature;

the spring disc causes the electrical contact to move between an open state and a closed state when the spring disc transitions between its first stable state and the second stable state; and

wherein a force required to move the spring disk from the first stable state to the second stable state is less than a force required to move the spring disk from the second stable state to the first stable state.

2. The thermostat of claim 1 further comprising:

a reset pin for manually applying a force to transition the spring disc from its second stable state to its first stable state.

3. The thermostat of claim 2, wherein the force that causes the spring disc to transition from its first stable state to its second stable state also moves the reset pin.

4. The thermostat of claim 1 further comprising:

a transfer pin disposed between the spring disc and the electrical contact for transferring movement of the spring disc to the electrical contact.

5. The thermostat of claim 1, wherein the temperature sensitive disc includes a bimetal disc that includes a first metal and a second metal, wherein the first metal has a different coefficient of thermal expansion that the second metal.

6. The thermostat of claim 1, wherein when the temperature sensitive disc and the spring disc are in their first stable states, the electrical contact is in a closed position.

7. The thermostat of claim 6, wherein when the spring disc is in its second stable state, the electrical contact is in an open position.

8. The thermostat of claim 1, wherein when the temperature sensitive disc and the spring disc are in their first stable states, the electrical contact is in an open position.

9. The thermostat of claim 8, wherein when the spring disc is in its second stable state, the electrical contact is in a closed position.

10. A thermostat comprising:

a housing defining a cavity;

an electrical contact;

a temperature sensitive disc that is configured to transition from a first stable state to a second stable state at a first temperature;

a spring disc positioned adjacent to the temperature sensitive disc, the spring disc have a first stable state and a second stable state, wherein the temperature sensitive disc applies a force to the spring disc that causes the spring disc to transition from its first stable state to its second stable state when the temperature sensitive disc transition from its first stable state to its second stable state at the first temperature;

the spring disc causes the electrical contact to move between an open state and a closed state when the spring disc transitions between its first stable state and the second stable state;

the spring disc having a relatively flat central region surrounded by a curved portion; and

the spring disc having a first side facing the temperature sensitive disc and a second side facing away from the temperature sensitive disc, wherein a transition between the relatively flat region and the curved portion on the first side of the spring disk is sharper than a transition between the relatively flat region and the curved portion on the second side of the spring disk.

11. The thermostat of claim 10, wherein a force required to move the spring disk from the first stable state to the second stable state is less than a force required to move the spring disk from the second stable state to the first stable state

12. The thermostat of claim 10 further comprising:

a reset pin for manually applying a force to transition the spring disc from its second stable state to its first stable state.

13. The thermostat of claim 12, wherein the force that causes the spring disc to transition from its first stable state to its second stable state also moves the reset pin.

14. The thermostat of claim 10, wherein the temperature sensitive disc includes a bimetal disc that includes a first metal and a second metal, wherein the first metal has a different coefficient of thermal expansion that the second metal.

15. The thermostat of claim 10, wherein when the temperature sensitive disc and the spring disc are in their first stable states, the electrical contact is in a closed position.

16. The thermostat of claim 15, wherein when the spring disc is in its second stable state, the electrical contact is in an open position.

17. A method of assembling a thermostat, the method comprising:

providing a housing

providing a spring disc having a first stable state and a second stable state;

providing a bimetallic disc having a first stable state and a second stable state;

snapping the spring disc from the first stable state to the second stable state; and

installing the spring disc, in the second stable state, adjacent to the bimetallic disc in the housing of the thermostat.

18. The method of claim 17, wherein a force required to transition the spring disc from the first stable state to the second stable state is larger than the force required to move the spring disk from the second stable state to the first stable state.

19. The method of claim 17, wherein when in the first stable state, a first side of the spring disc has a concave shape and a second side of the spring disc has a convex shape.

20. The method of claim 19, wherein when in the second stable state, the second side of the spring disc has a concave shape and the first side of the spring disc has a convex shape.