Mechanical fuse striker

Patent metadata

Field	Value
Publication number	US-12080504-B2
Application number	US-202117534031-A
Country	US
Kind code	B2
Filing date	Nov 23, 2021
Priority date	Nov 23, 2020
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

A strike pin assembly for a fuse assembly in which the strike pin assembly is maintained in a locked position by a holding force of a filament and an interference provided by a plurality of retention bodies. Upon a breakage of the filament, such as, for example, in response to heat generated by operation of a fuse element, a trigger can be displaced via a first biasing force in a distal direction such that the trigger is positioned at a location that does not impede an inward displacement of a plurality of retention bodies from a recess of a firing pin. Upon the inward displacement of the retention bodies, a second biasing force can displace the firing pin in the distal direction such that a portion of the firing pin can protrude out from an adapter of the strike pin assembly.

First claim

The invention claimed is:

1. A fuse assembly comprising:
a casing having an interior region, the interior region housing at least a portion of a fuse element and a filament; and
a strike pin assembly comprising:
a cap coupled to the casing, the cap having a plurality of openings;
an adapter coupled to the cap;
a firing pin housed within the adapter, at least a distal end of the cap being positioned within an aperture of the firing pin when the strike pin assembly is at a locked position, the aperture having a recess that is separated from a proximate end of the firing pin by a retention wall, at least a portion of the firing pin sized to be displaced to a position outside of the adapter upon a release of the strike pin assembly from the locked position;
a plurality of retention bodies, at least a portion of the plurality of retention bodies being positioned, when the strike pin assembly is at the locked position, within the recess and at least partially extending into an adjacent opening of the plurality of openings of the cap;
a trigger being releasably secured within a cavity of the cap by the filament when the strike pin assembly is in the locked position, at least a portion of an engagement section of the trigger being positioned adjacent to the plurality of openings when the strike pin assembly is in the locked position and sized to prevent removal of the plurality of retention bodies from the recess of the firing pin through the plurality of openings, the trigger further including a recessed section sized to accommodate a displacement of each of the plurality of retention bodies from the recess of the firing pin and at least partially through the plurality of openings and into the cavity of the cap in response to the release of the strike pin assembly from the locked position;

a first biasing element positioned to displace, in response to a breakage in the filament, the trigger in a distal direction and to a location at which the recessed section accommodates the displacement of each of the plurality of retention bodies; and
a second biasing element positioned to displace the firing pin in the distal direction in response to the displacement of each of the plurality of retention bodies.

2. The fuse assembly of claim 1 , wherein the plurality of openings of the cap are positioned adjacent to a distal end of the cap, a proximate end of the cap being coupled to the casing.

3. The fuse assembly of claim 1 , wherein the cap further comprises a base portion, a first projection, and a second projection, the base portion being coupled to the cap, the first projection being coupled to the adapter, and the second projection housing the trigger and the first biasing element, the plurality of openings extending through the second projection.

4. The fuse assembly of claim 3 , wherein the first projection of the cap is threadingly coupled to the adapter.

5. The fuse assembly of claim 4 , wherein the cavity of the cap is a second cavity of the second projection, the first projection having a first cavity that is in fluid communication with an inner region of the base portion of the cap, the first cavity and the second cavity being at least partially separated by a cavity wall, the cavity wall having an opening sized to accommodate passage of the filament through the first cavity and into the second cavity.

6. The fuse assembly of claim 5 , wherein the first cavity provides a central support location for at least one of the fuse element and a support core for the fuse element.

7. The fuse assembly of claim 5 , wherein the fuse element comprises a polyetheretherketone (PEEK) material.

8. The fuse assembly of claim 1 , wherein the retention wall of the firing pin includes an inner surface that abuts the plurality of retention bodies when the firing pin is at the locked position, the inner surface being tapered to facilitate the displacement of the plurality of retention bodies.

9. The fuse assembly of claim 1 , wherein the firing pin has a base portion and a projection portion, the base portion being housed within a first bore of the adapter, at least a portion of the projection portion being positioned in a second bore of the adapter and configured to extend from the adapter in response to the strike pin assembly being released from the locked position.

10. The fuse assembly of claim 9 , wherein the adapter includes a bore retention wall at a distal end of the first bore that is sized to abut a shoulder of the firing pin to limit a distance of displacement of the firing pin in the distal direction.

11. The fuse assembly of claim 10 , further including a first seal positioned about the projection portion of the firing pin and against an inner surface of the second bore.

12. The fuse assembly of claim 11 , further including a second seal positioned about a distal end of the adapter, and wherein a distal end of the projection portion is configured to puncture the second seal.

13. The fuse assembly of claim 1 , wherein the second biasing element has a spring force that is larger than a spring force of the first biasing element.

14. The fuse assembly of claim 9 , wherein at least a portion of the second biasing element is axially positioned to overlap at least a portion of the first biasing element.

15. A method for operating a strike pin assembly of a fuse assembly comprising:
releasing a holding force provided by a filament of the fuse assembly on a trigger of the strike pin assembly, the holding force maintaining the trigger at a position that prevents a displacement of a plurality of retention bodies from a recess of a firing pin of the strike pin assembly;
displacing, upon the release of the holding force and via a biasing force of a first biasing element, the trigger in a first direction toward a distal end of the strike pin assembly;
displacing, upon displacement of the trigger, the plurality of retention bodies from the recess of the firing pin; and
displacing, in response to the displacement of the plurality of retention bodies and via a biasing force of a second biasing element, the firing pin in the first direction such that a distal end of the firing pin protrudes out of an adapter of the strike pin assembly.

16. The method of claim 15 , wherein the releasing of the holding force comprises breaking the filament in response to a temperature generated by operation of a fuse element of the fuse assembly.

17. The method of claim 16 , wherein displacing the trigger comprises displacing the trigger to a location at which a recessed section of the trigger is positioned to accommodate the displacement of at least a portion of each of the plurality of retention bodies through an adjacent opening in a cap of the strike pin assembly.

Assignees

• Abb Schweiz Ag

Inventors

• Cawood Matthew
• Motes Aaron

Classifications

• H01H31/127

  Drop-out fuses · CPC title

• H01H31/125

  with a pivotally supported fuse, hanging on a fixed contact in the open position of the switch (H01H31/127 takes precedence) · CPC title

• H01H85/042

  General constructions or structure of high voltage fuses, i.e. above 1000 V · CPC title

• H01H85/303 Primary

  Movable indicating elements · CPC title