Burn wire release mechanism for spacecraft and terrestrial applications

Patent metadata

Field	Value
Publication number	US-10351269-B2
Application number	US-201414448366-A
Country	US
Kind code	B2
Filing date	Jul 31, 2014
Priority date	Sep 29, 2011
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A burn wire release mechanism for a spacecraft or other system having two masses initially held together by a pretensioned loop, with a spring configured to push the masses apart. The burn wire release system includes at least one burn wire held in contact with the pretensioned loop material. When an electrical current flows through the burn wire, the wire heats up and severs the pretensioned loop, and the masses are pushed apart by the spring.

First claim

The invention claimed is:

1. A burn wire release system for separating components held together by a cord, comprising:
at least one burn wire release mechanism, each mechanism having a resistively heated burn wire that is spring pre-loaded in contact with the cord, wherein in operation, a controlled current flows through the burn wire of at least one of the at least one burn wire release mechanisms, heating the burn wire sufficiently to cut through the cord,
wherein each burn wire release mechanism has two dowel pins, each dowel pin having a compression spring situated between an upper saddle and a lower saddle.

2. The system according to claim 1 , wherein the at least one burn wire release mechanism is at least two burn wire release mechanisms for redundancy, only one of which must operate to cut through the cord.

3. The system according to claim 1 , wherein each of the compression springs is configured to apply a spring stroke and preload the burn wire against the cord.

4. The system according to claim 3 , further comprising of snap rings located in grooves on the surface of each of the dowel pins, operable to keep the saddles spaced apart at a predetermined distance.

5. The system according to claim 4 , wherein the predetermined distance is smaller than the compression spring free length.

6. The system according to claim 1 , wherein the burn wire is secured in a V shape between button head screws and ring terminals, the ring terminals providing both the mechanical and electrical connection for the burn wire release mechanism.

7. The system according to claim 6 , wherein the burn wire is electrically isolated from components other than the ring terminals by separation or hard anodizing on other components in contact with the burn wire.

8. The system according to claim 1 , wherein the burn wire mechanisms are operable in both air and vacuum environments.

9. The system according to claim 1 , wherein the burn wire comprises nichrome.

10. The system according to claim 1 , wherein the burn wire comprises 30 AWG, Chromel C type nichrome.

11. The system according to claim 1 , wherein the burn wire has a free length of between 0.4 inches and 1.25 inches.

12. The system according to claim 1 , wherein the current supplied to the burn wire is between 1.55 and 1.65 Amperes.

13. The system according to claim 1 , wherein the cord comprises a polymer.

14. The system according to claim 13 , wherein the cord comprises spun liquid crystal polymer.

15. A burn wire release system for separating components held together by a cord, comprising:
at least one burn wire release mechanism, each mechanism having a resistively heated burn wire that is spring pre-loaded in contact with the cord, wherein in operation, a controlled current flows through the burn wire of at least one of the at least one burn wire release mechanisms, heating the burn wire sufficiently to cut through the cord,
wherein the burn wire is secured in a V shape between button head screws and ring terminals, the ring terminals providing both the mechanical and electrical connection for the burn wire release mechanism.

16. The system according to claim 15 , wherein the burn wire is electrically isolated from components other than the ring terminals by separation or hard anodizing on other components in contact with the burn wire.

17. The system according to claim 15 , wherein the burn wire mechanisms are operable in both air and vacuum environments.

18. The system according to claim 15 , wherein the burn wire comprises nichrome.

19. The system according to claim 15 , wherein the burn wire comprises 30 AWG, Chromel C type nichrome.

20. The system according to claim 15 , wherein the burn wire has a free length of between 0.4 inches and 1.25 inches.

21. The system according to claim 15 , wherein the current supplied to the burn wire is between 1.55 and 1.65 Amperes.

22. The system according to claim 15 , wherein the cord comprises a polymer.

23. The system according to claim 22 , wherein the cord comprises spun liquid crystal polymer.

24. The system according to claim 15 , wherein each burn wire release mechanism has two dowel pins, each dowel pin having a compression spring situated between an upper saddle and a lower saddle, and
wherein each of the compression springs are configured to apply a spring stroke and preload the burn wire against the cord.

25. The system according to claim 24 , further comprising of snap rings located in grooves on the surface of each of the dowel pins, operable to keep the saddles spaced apart at a predetermined distance.

Assignees

• Thurn Adam
• Us Gov Sec Navy

Inventors

• Thurn Adam

Classifications

• B64G1/363

  using sun sensors · CPC title

• B64G1/648 Primary

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• B64G1/645

  Separators · CPC title

• B64G1/44

  using radiation, e.g. deployable solar arrays · CPC title

• B64G1/40

  Arrangements or adaptations of propulsion systems · CPC title