Linkage-based off-stop apparatus and methods for circuit breakers

Patent metadata

Field	Value
Publication number	US-9859083-B1
Application number	US-201615225935-A
Country	US
Kind code	B1
Filing date	Aug 2, 2016
Priority date	Aug 2, 2016
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

An off-stop mechanism for a circuit breaker. Off-stop mechanism includes a handle moveable to an OFF configuration, the handle including a blocking engagement portion, a blocking member pivotally coupled at a pivot location, a linkage coupled between a cross bar housing and a linkage attachment location of the blocking member, the linkage being configured to: position the blocking member in an unblocked orientation when the main contacts are not fused together, and in a blocked orientation when the main contacts are fused together, wherein blocking member in the blocked orientation engages the blocking engagement portion as the operating handle is moved to the OFF configuration wherein the engagement places the blocking member in compression between the pivot location and the blocking contact portion. Circuit breakers including the off-stop mechanism and methods of operating a circuit breaker are also provided, as are other aspects.

First claim

What is claimed is:

1. An off-stop mechanism for a circuit breaker, comprising:
an operating handle moveable to an OFF configuration, provided main contacts of the circuit breaker are not fused together, the operating handle including a blocking engagement portion;
a cross bar housing;
a blocking member pivotally coupled at a pivot location and rotatable between an unblocked orientation and a blocked orientation, the blocking member including a linkage attachment location and a blocking contact portion; and
a linkage coupled between the cross bar housing at a first end and the linkage attachment location on the blocking member at a second end, the linkage being configured to:
position the blocking member in the unblocked orientation when the main contacts are not fused together, and
configure the blocking member to a blocked orientation in response to the main contacts being fused together, wherein the blocking member in the blocked orientation is configured to engage the blocking engagement portion as the operating handle is moved to the OFF configuration and the engagement places the blocking member under a compressive force between the pivot location and the blocking contact portion.

2. The off-stop mechanism for a circuit breaker of claim 1 , wherein the operating handle is moveable relative to a side frame and the blocking member is pivotally coupled to the side frame.

3. The off-stop mechanism for a circuit breaker of claim 1 , wherein the linkage comprises an only linkage coupled to the cross bar housing.

4. The off-stop mechanism for a circuit breaker of claim 1 , wherein the blocking member comprises a blocking contact portion and a nose portion, the blocking contact portion adapted to be contacted by the blocking engagement portion of the operating handle and the nose portion is coupled to a return spring.

5. The off-stop mechanism for a circuit breaker of claim 1 , wherein the linkage attachment location and the blocking contact portion are positioned on opposing sides of the pivot location.

6. The off-stop mechanism for a circuit breaker of claim 1 , wherein the blocking engagement portion is formed on one side of a U-shaped portion of the operating handle.

7. The off-stop mechanism for a circuit breaker of claim 1 , wherein the blocking member includes a pilot and a head on the pilot, and the linkage includes an aperture on the second end, and the aperture includes a dimension large enough to be received over the head.

8. The off-stop mechanism for a circuit breaker of claim 1 , comprising:
a side plate including a hole formed therein,
a nose portion of the blocking member, and
a return spring coupled between the nose portion and the hole formed in the side plate.

9. The off-stop mechanism for a circuit breaker of claim 1 , comprising a recess formed in the blocking member, and wherein the second end of the linkage is configured to be rotatable in the recess.

10. The off-stop mechanism for a circuit breaker of claim 1 , wherein the linkage comprises a shaft rigidly attached at the first end of the linkage, wherein the shaft is pivotally mounted to the cross bar housing.

11. The off-stop mechanism for a circuit breaker of claim 10 , wherein the shaft is slidably mounted in a slot formed in the cross bar housing.

12. The off-stop mechanism for a circuit breaker of claim 10 , wherein the shaft comprises a smaller dimension portion, a washer and a clip coupled to the smaller dimension portion wherein the cross bar housing is received between the washer and the clip.

13. The off-stop mechanism for a circuit breaker of claim 1 , wherein in the blocked orientation, a force vector acting on the blocking contact portion passes substantially through the pivot location.

14. The off-stop mechanism for a circuit breaker of claim 1 , comprising a relief in the blocking member between the pivot location and the blocking contact portion, wherein the relief is configured to contact a trip shaft when the blocking member is in the blocked orientation.

15. The off-stop mechanism for a circuit breaker of claim 1 , comprising a length of the linkage between a cross bar pivot and the linkage attachment location is at least two times larger than a distance between the pivot location and the blocking contact portion.

16. The off-stop mechanism for a circuit breaker of claim 1 , comprising in the unblocked orientation, the blocking member and linkage are configured so that the blocking engagement portion moves past the blocking contact portion.

17. The off-stop mechanism for a circuit breaker of claim 1 , comprising in the blocked orientation, the linkage attachment location is located between the pivot location and operating handle.

18. A circuit breaker, comprising:
first and second side frames;
an operating handle pivotally mounted to the side frames, the operating handle moveable to an OFF configuration provided main contacts of the circuit breaker are not fused together, the operating handle including a first leg and a second leg, and a blocking engagement portion on one of the first and second legs;
a cross bar housing;
a blocking member pivotally coupled to one of the first and second side frames at a pivot location and rotatable between an unblocked orientation and a blocked orientation, the blocking member including a linkage attachment location and a blocking contact portion; and
a linkage coupled between the cross bar housing at a first end and the linkage attachment location on the blocking member at a second end, the linkage being configured to:
position the blocking member in the unblocked orientation provided that the main contacts are not fused together, and
configure the blocking member to the blocked orientation if the main contacts are fused together, wherein the blocking member in the blocked orientation is configured to engage the blocking engagement portion as the operating handle is moved to the OFF configuration and the engagement places the blocking member under a compressive force between the pivot location and the blocking contact portion.

19. A method of operating a circuit breaker including an off-stop mechanism, the method comprising:
providing an operating handle moveable towards an OFF configuration to separate main contacts, the operating handle including a blocking engagement portion;
providing a blocking member including a blocking contact portion, the blocking member pivotally mounted at a pivot location, a cross bar housing, and a linkage pivotally coupled between the cross bar housing and the blocking member, the blocking member moveable between a blocked configuration and an unblocked configuration by the linkage dependent upon whether main contacts are fused;
moving the operating handle towards the OFF configuration; and
positioning the blocking member in the blocked configuration with the linkage as the cross bar housing fails to rotate due to the main contacts being fused; and
blocking further motion to the OFF configuration by contact between the blocking engagement portion of the operating handle and the blocking contact portion of the blocking member, wherein the blocking compresses the blocking member between the blocking contact portion and the pivot location.

Assignees

• Siemens Ag

Inventors

• Thomas Stephen Scott

Classifications

• H01H2071/502

  with direct contact between manual operator and welded contact structure · CPC title

• H01H71/1054 Primary

  Means for avoiding unauthorised release · CPC title

• H01H71/525

  comprising a toggle between cradle and contact arm and mechanism spring acting between handle and toggle knee · CPC title

• H01H71/04

  Means for indicating condition of the switching device {(by means of an auxiliary contact H01H71/46)} · CPC title

• H01H2071/046

  exclusively by position of operating part, e.g. with additional labels or marks but no other movable indicators · CPC title