Disconnect switch with integrated thermal breaker

Patent metadata

Field	Value
Publication number	US-9911567-B2
Application number	US-201514733369-A
Country	US
Kind code	B2
Filing date	Jun 8, 2015
Priority date	Jun 8, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A disconnect switch is disclosed with an integrated thermal breaker that can be disposed between a source of power and a circuit to be protected. The disconnect switch can comprise a housing, a first terminal coupled to a power source and a second terminal coupled to a load. The first terminal and the second terminal can be partially included in the housing. The disconnect switch comprises a bi-metal thermal conductive element made from at least two metal sheets with different thermal expansion coefficients and having a concave shape that engages the first and second terminals. Upon occurrence of an overload condition, heat flowing through the bi-metal thermal conductive element causes the concave shape to retract to a convex shape and disengage the bi-metal thermal conductive element from the first and the second terminals.

First claim

What is claimed is:

1. A circuit protection assembly for a mechanical disconnect switch having an integrated thermal breaker comprising:
a housing;
a first terminal;
a second terminal, the first terminal and the second terminal at least partially disposed within the housing;
a bi-metal thermal conductive element, the bi-metal thermal conductive element being made of at least two metal sheets having different coefficients of thermal expansion; and
an operating mechanism including a shaft coupling the bi-metal thermal conductive element to a switch, the switch being rotatable about an axis of the shaft to move the bi-metal thermal conductive element between a first position, in which the bi-metal thermal conductive element cannot engage the first terminal and the second terminal, and a second position, in which the bi-metal thermal conductive element can engage the first terminal and the second terminal,
the bi-metal thermal conductive element having a concave shape while electrically engaged with the first terminal and the second terminal, wherein upon occurrence of an overload condition, heat flowing through the bi-metal thermal conductive element causes the concave shape to retract to a convex shape and disengages the bi-metal thermal conductive element from the first terminal and the second terminal;
wherein the bi-metal thermal conductive element is configured to automatically return to the concave shape and reestablish electrical engagement with the first terminal and the second terminal upon the bi-metal thermal conductive element cooling to a predetermined temperature.

2. The circuit protection assembly of claim 1 , wherein the bi-metal thermal conductive element comprises one of a metal alloy, nickel, iron, manganese, chromium, copper, steel, brass, aluminum, or a combination thereof.

3. The circuit protection assembly of claim 1 , wherein the bi-metal thermal conductive element is configured to return to the concave shape upon the bi-metal thermal conductive element being moved to the first position.

4. The circuit protection assembly of claim 3 , wherein a load current can flow from a power source to a load through the bi-metal thermal conductive element while the bi-metal thermal conductive element electrically engages with the first terminal and the second terminal.

5. The circuit protection assembly of claim 1 , wherein the bi-metal thermal conductive element is calibrated to a predetermined amperage.

6. The circuit protection assembly of claim 1 , wherein the mechanical disconnect switch is a high current circuit breaker.

7. A method of manufacturing a mechanical disconnect switch having an integrated thermal breaker comprising:
providing a housing;
providing a first terminal;
providing a second terminal, the first terminal and the second terminal at least partially included in the housing;
providing a bi-metal thermal conductive element, the bi-metal thermal conductive element being made of at least two metal sheets with different thermal expansion coefficients; and
providing a disconnect switch coupled to the bi-metal thermal conductive element by a shaft, the disconnect switch being rotatable about an axis of the shaft to move the bi-metal thermal conductive element between a first position, in which the bi-metal thermal conductive element cannot engage the first terminal and the second terminal, and a second position, in which the bi-metal thermal conductive element can engage the first terminal and the second terminal, the bi-metal thermal conductive element having a concave shape while electrically engaged with the first terminal and the second terminal, wherein upon occurrence of an overload condition, heat flowing through the bi-metal thermal conductive element causes the concave shape to retract to a convex shape and disengage the bi-metal thermal conductive element from the first terminal and the second terminal,
wherein the bi-metal thermal conductive element is configured to automatically return to the concave shape and reestablish electrical engagement with the first terminal and the second terminal upon the bi-metal thermal conductive element cooling to a predetermined temperature.

8. The method of manufacturing of claim 7 , wherein the bi-metal thermal conductive element is configured to return to the concave shape when the bi-metal thermal conductive element is moved to the first position.

Assignees

• Littelfuse Inc
• Littlfuse Inc

Inventors

• Schwartz Geoffrey
• Thomas Joe
• Scribner Dana

Classifications

• H01H89/04 Primary

  Combination of a thermally actuated switch with a manually operated switch · CPC title

• H01H19/14

  Operating parts, e.g. turn knob · CPC title

• H01H37/54

  wherein the bimetallic element is inherently snap acting · CPC title

• H01H71/16

  with bimetal element {(combined with detection of imbalance of two or more currents H01H83/223)} · CPC title

• H01H37/52

  actuated due to deflection of bimetallic element · CPC title