Encapsulated explosion-proof pilot light

• US 5,821,695 A
• Filed: 08/06/1996
• Issued: 10/13/1998
• Est. Priority Date: 08/06/1996
• Status: Expired due to Fees

• Current Assignee: Appleton Electric LLC (Emerson Electric Company)
• Original Assignee: Appleton Electric LLC (Emerson Electric Company)
• Inventors: Mina, Nabil L., Vilanilam, Santosh
• Primary Examiner(s): SHINGLETON, MICHAEL B
• Application Number:
  US08/693,363
• Time in Patent Office: 798 Days
• Field of Search: 315/56, 315/71, 315/58, 315/324, 362/800, 362/29, 439/375
• US Class Current: 315/58
• CPC Class Codes: F21V 21/043 actuated by screwing
• CPC Class Codes: F21V 25/12 Flameproof or explosion-proof arrangements
• CPC Class Codes: F21V 31/04 Provision of filling media
• CPC Class Codes: F21W 2111/00 Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/00 Circuit arrangements for operating light-emitting diodes [LED]
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A housing having a cavity is in sealing engagement with a glass jewel which also contains a cavity; these two cavities cooperate to form a closed chamber. A frame supporting terminal plates is mounted within the chamber. The frame also mounts a circuit board which in turn mounts a plurality of LEDs. An encapsulating material fills all of the spaces within the chamber.

Claims

1. An encapsulated explosion-proof pilot light assembly comprising:

(a) a housing defining a first cavity open at one end of the housing and having a bore formed therein, said bore for receiving an encapsulating material;

(b) a dome-like transparent member mounted to said housing at said one end thereof and defining a second cavity in communication with the first cavity, said housing and said transparent member cooperating to form a substantially closed chamber consisting of said first and second cavities;

(c) a frame mounted substantially within said first cavity, said frame including upper and lower annular members having open centers that allows encapsulating material to pass therethrough, said upper and lower annular members joined in spaced apart relationship by a plurality of legs defining openings therebetween;

(d) a circuit board mounted to said frame adjacent said upper annular member;

(e) at least one LED device in a plurality of circuit elements mounted by said circuit board; and

(f) an encapsulating material substantially filling all of the open spaces within said chamber.

2. The pilot light assembly according to claim 1 wherein said circuit board is circular in shape and is mounted in concentric relationship with said upper annular member, the diameter of said circuit board being less than the inside diameter of said upper annular member thereby defining a substantially annular opening between said circuit board and said upper annular member to facilitate the flow of encapsulating material.

3. The pilot light assembly according to claim 1 wherein said transparent member is a glass jewel.

4. The pilot light assembly according to claim 1 wherein said encapsulating material is a silicone elastomer.

5. The pilot light assembly according to claim 1 wherein said circuit board mounts a plurality of LED devices.

6. The pilot light assembly according to claim 5 wherein said transparent member and said LED devices are of the same color.

7. The pilot light assembly according to claim 1 wherein said frame has a plurality of openings to facilitate the flow of said encapsulating material.

8. The pilot light assembly according to claim 1 wherein said circuit board has at least one opening to facilitate the flow of said encapsulating material.

9. The pilot light assembly according to claim 1 wherein the encapsulating material provides good thermal conductivity, is optically clear and offers resistance to impact tests.

10. An apparatus as claimed in claim 1 including:

a projection connected to said upper annular member for supporting said transparent member.

11. An apparatus as claimed in claim 1 including:

a projection connected to said housing for supporting said frame.

12. An apparatus as claimed in claim 1 including:

a projection connected to said lower member of said frame for contacting a sidewall of said cavity of said housing.

13. An apparatus as claimed in claim 1 wherein:

said first cavity has a frusto-conical surrounding wall; and

said lower annular member of said frame has a smaller diameter than the upper annular member of said frame.

14. An apparatus as claimed in claim 1 wherein:

said housing includes a plurality of T-shaped slots in communication with said cavity; and

said circuit board includes at least one opening.

15. An apparatus as claimed in claim 1 wherein:

said housing has an outer threaded surface and an annular ledge; and

including

a nut adapted to be threadedly engaged to said housing whereby said nut and said annular ledge cooperate to attach said assembly to a wall;

a bushing; and

a gasket whereby rotating said nut causes said bushing to force said gasket to bear against said housing.

16. An apparatus as claimed in claim 1 including:

electrically conductive plates mounted to the lower annular member of said frame.

17. An encapsulated-explosion proof pilot light assembly comprising:

(a) a generally cylindrical housing having an internal wall defining a first cavity at one end of the housing and having a bore formed therein, said bore for receiving an encapsulating material;

(b) a dome-like transparent member mounted to said housing at said one end thereof and defining a second cavity in communication with said first cavity, said housing and said transparent member cooperating to form a substantially closed chamber consisting of said first and second cavities;

(c) a frame including upper and lower annular members each having open centers that allows encapsulating material to pass therethrough, said upper and lower annular members joined in spaced apart relationship by a plurality of legs defining openings therebetween, the frame being mounted substantially within said first cavity and in concentric relationship therewith;

(d) a disc-like circuit board mounted to said frame adjacent said upper annular member and in concentric relationship therewith;

(e) at least one LED device in a plurality of circuit elements mounted by said circuit board; and

(f) encapsulating material substantially filling all of the open space within said chamber.

18. The pilot light assembly according to claim 17 wherein said transparent member is a glass jewel.

19. The pilot light assembly according to claim 17 wherein said encapsulating material is a silicone elastomer.

20. The pilot light assembly according to claim 17 wherein said circuit board mounts a plurality of LED devices.

21. The pilot light assembly according to claim 20 wherein said transparent member and said LED devices are of the same color.

22. The pilot light assembly according to claim 17 wherein the encapsulating material provides good thermal conductivity, is optically clear and offers resistance to impact tests.

23. An apparatus as claimed in claim 17 including:

a projection connected to said upper annular member for supporting said transparent member.

24. An apparatus as claimed in claim 17 including:

a projection connected to said housing for supporting said frame.

25. An apparatus as claimed in claim 17 including:

a projection connected to said lower member of said frame for contacting a sidewall of said cavity of said housing.

26. An apparatus as claimed in claim 17 wherein:

said first cavity has a frusto-conical surrounding wall; and

said lower annular member of said frame has a smaller diameter than the upper annular member of said frame.

27. An apparatus as claimed in claim 17 wherein:

said housing includes a plurality of T-shaped slots in communication with said cavity.

28. An apparatus as claimed in claim 17 wherein:

said housing has an outer threaded surface and an annular ledge; and

including

a nut adapted to be threadedly engaged to said housing whereby said nut and said annular ledge cooperate to attach said assembly to a wall;

a bushing; and

a gasket whereby rotating said nut causes said bushing to force said gasket to bear against said housing.

29. An apparatus as claimed in claim 17 including:

electrically conductive plates mounted to the lower annular member of said frame.