Self-resetting biasing devices for current limiting circuit breaker trip systems

Patent metadata

Field	Value
Publication number	US-9899176-B2
Application number	US-201615092905-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Apr 7, 2016
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

A circuit breaker including a case, a trip mechanism, and a trip lever moveable between a first position and a second position. The trip lever includes a first end selectively contacting the trip mechanism and a second end opposite the first end. The circuit breaker also includes a biasing device including a housing coupled to the case and a lever arm coupled to the housing. The lever arm includes an engagement surface in contact with the second end and configured to move between an initial position corresponding to the first position and a final position corresponding to the second position. The biasing device also includes a bias member extending between the housing and the lever arm and biasing the engagement surface against the second end. The lever arm exerts a first torque in the first position and exerts a second torque different from the first torque in the second position.

First claim

What is claimed is:

1. A circuit breaker including a case, said circuit breaker comprising:
a trip mechanism;
a trip lever coupled to the case and configured to move between a first position and a second position, said trip lever comprising a first end that selectively contacts said trip mechanism and a second end opposite said first end, wherein said trip lever first end does not contact said trip mechanism in the first position, and wherein the first position corresponds to a low current condition; and
a biasing device comprising:
a housing coupled to the case;
a lever arm coupled to said housing and comprising an engagement surface in contact with said second end, said lever arm configured to move between an initial position corresponding to the first position and a final position corresponding to the second position; and
a bias member extending between said housing and said lever arm and biasing said engagement surface against said trip lever second end such that said engagement surface contacts said trip lever second end in both the trip lever first position corresponding to the low current condition and the trip lever second position, wherein said lever arm exerts a first torque upon said trip lever in the first position and exerts a second torque upon said trip lever in the second position, and wherein a value of the first torque is different from a value of the second torque.

2. A circuit breaker in accordance with claim 1 , wherein said bias member comprises at least one of a coil spring, a torsion spring, a tension spring, and a leaf spring.

3. A circuit breaker in accordance with claim 1 further comprising an additional bias member comprising at least one of a leaf spring, a torsion spring, a ball catch mechanism, and a cam-biased spring mechanism, said additional bias member extending between said housing and said lever arm, said additional bias member further biasing said lever arm against said second end.

4. A circuit breaker in accordance with claim 1 , wherein said bias member comprises at least two bias members.

5. A circuit breaker in accordance with claim 1 further comprising at least one additional trip lever arranged to selectively contact said lever arm.

6. A circuit breaker in accordance with claim 1 further comprising a second lever arm coupled to said housing.

7. A circuit breaker in accordance with claim 1 further comprising a tip hingedly coupled to said trip mechanism.

8. A circuit breaker in accordance with claim 1 , wherein said second end comprises a first surface and a second surface oriented substantially orthogonal to said first surface.

9. A circuit breaker in accordance with claim 8 , wherein said second surface is arcuate.

10. A circuit breaker in accordance with claim 1 , wherein a torque characteristic of said trip lever is non-linear over a range of motion of said trip lever.

11. A biasing device for a circuit breaker having a case, a trip mechanism, and a trip lever coupled to the case and configured to move between a first position and a second position, the trip lever including a first end that selectively contacts the trip mechanism and a second end opposite the first end, wherein the trip lever first end does not contact the trip mechanism in the first position, and wherein the first position corresponds to a low current condition, said biasing device comprising:
a housing coupled to the case;
a lever arm coupled to said housing and comprising an engagement surface in contact with the second end, said lever arm configured to move between an initial position corresponding to the first position and a final position corresponding to the second position; and
a bias member extending between said housing and said lever arm and biasing said engagement surface against the trip lever second end such that said engagement surface contacts the trip lever second end in both the trip lever first position corresponding to the low current condition and the trip lever second position, wherein said lever arm exerts a first torque upon the trip lever in the first position and exerts a second torque upon the trip lever in the second position, and wherein a value of the first torque is different from a value of the second torque.

12. A biasing device in accordance with claim 11 , wherein said housing comprises a stop surface, and wherein said lever arm further comprises a protrusion that contacts said stop surface to restrict a movement of said lever amt.

13. A biasing device in accordance with claim 11 , wherein said bias member comprises at least one of a coil spring, a torsion spring, a tension spring, and a leaf spring.

14. A biasing device in accordance with claim 11 , wherein said lever arm is rotatably coupled to said housing.

15. A biasing device in accordance with claim 11 further comprising an additional bias member comprising at least one of a leaf spring, a torsion spring, a ball catch mechanism, and a cam-biased spring mechanism, said additional bias member extending between said housing and said lever arm, said additional bias member further biasing said lever arm against the second end.

16. A biasing device in accordance with claim 11 further comprising a second lever arm coupled to said housing.

17. A biasing device in accordance with claim 11 , wherein a torque characteristic of the trip lever is non-linear over a range of motion of the trip lever.

18. A method of assembling a circuit breaker, said method comprising:
coupling a trip mechanism to a circuit breaker case;
coupling a trip lever to the circuit breaker case, the trip lever moveable between a first position and a second position, the trip lever including a first end that selectively contacts the trip mechanism and a second end opposite the first end, wherein the trip lever first end does not contact the trip mechanism in the first position, and wherein the first position corresponds to a low current condition; and
coupling a biasing device to the circuit breaker, the biasing device including a housing coupled to the circuit breaker case and a lever arm coupled to the housing, the lever arm moveable between an initial position corresponding to the first position and a final position corresponding to the second position, the lever arm having an engagement surface that contacts the second end, the biasing device further including a bias member extending between the housing and the lever arm, wherein the bias member biases the engagement surface against the trip lever second end such that the engagement surface contacts the trip lever second end in both the trip lever first position corresponding to the low current condition and the trip lever second position, wherein the lever arm exerts a first torque upon the trip lever in the first position and exerts a second torque upon the trip lever in the second position to facilitate self-resetting of the trip lever, wherein a value of the first torque is different from a value of the second torque, and wherein a torque characteristic of the trip lever is non-linear over a range of motion of the trip lever.

19. A method device in accordance with claim 18 , wherein the lever arm is rotatably coupled to the housing.

20. A biasing device in accordance with claim 1 , wherein said lever arm is rotatably coupled to said housing.

Assignees

• Gen Electric

Inventors

• Thorat Hemraj Keda
• Mittu Mahadeva Mallappa
• Bose Amit
• Rane Mahesh Jaywant
• Kadam Gajendra Vijaykumar

Classifications

• H01H71/505 Primary

  Latching devices between operating and release mechanism · CPC title

• H01H71/128 Primary

  Manual release or trip mechanisms, e.g. for test purposes (two similar push buttons for closing or resetting and opening or tripping H01H71/58; test switches for earth fault circuit breakers H01H83/04) · CPC title

• H01H71/24

  Electromagnetic mechanisms · CPC title

• H01H71/12 Primary

  Automatic release mechanisms with or without manual release · CPC title

• H01H71/52

  actuated by lever · CPC title