US3723930A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oil immersible current limiting fuse assembly
Assignee: General Electric Co
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Filing: 1972-02-10
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Granted: 1973-03-27
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Expires: 1992-02-10
Abstract
Abstract An oil immersible current limiting fuse assembly is provided by encapsulating a current limiting fuse in a homogeneous, molded epoxy material and providing resilient seal means adjacent the axial ends of the assembly, between the epoxy encapsulation and the fuse. The fuse assembly is further characterized by incorporating a vent passageway through one of the fuse terminals, which is effective to vent gas from the interior of the fuse during its manufacture in order to assure the maintenance of a fluid-tight sealing relationship between the fuse and the encapsulating epoxy.
Inventors
- 👤 R Koch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:10
CPC Classifications
H; H01; H01H; H01H85/00; H01H85/02; H01H85/04; H01H85/041; H01H85/044; H01H85/0013; H01H85/0021; H01H85/003
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
138 words
An immersible current limiting fuse assembly comprising a fuse having a hollow tubular casing formed of rigid dielectric material, first and second metallic end caps mounted respectively over opposite ends of said casing in sealing relationship therewith, at least one fusible link electrically connected to form a circuit through said casing between the first and second end cap; in combination with the improvement comprising, first and second elongated electrical terminal members mounted, respectively, on the first and second end caps and extending outward from them, a rigid body of essentially void-free epoxy resin mounted on the outer surface of said fuse to completely encapsulate it, and means defining first and second bands of resilient elastomeric material mounted, respectively, around the peripheries of said end caps to form fluid-tight seals between them and the body of encapsulating epoxy resin.
Claim 2
Dependent Claim
138 words
An immersible current limiting fuse assembly comprising a fuse having a hollow tubular casing formed of rigid dielectric material, first and second metallic end caps mounted respectively over opposite ends of said casing in sealing relationship therewith, at least one fusible link electrically connected to form a circuit through said casing between the first and second end cap; in combination with the improvement comprising, first and second elongated electrical terminal members mounted, respectively, on the first and second end caps and extending outward from them, a rigid body of essentially void-free epoxy resin mounted on the outer surface of said fuse to completely encapsulate it, and means defining first and second bands of resilient elastomeric material mounted, respectively, around the peripheries of said end caps to form fluid-tight seals between them and the body of encapsulating epoxy resin.
Claim 3
Dependent Claim
74 words
An invention as defined in claim 1 wherein the body of epoxy resin is bonded to the tubular casing to form a void-free interface therewith, and wherein the epoxy resin has a coefficient of thermal expansion that is sufficiently similar to the coefficient of thermal expansion of the fuse casing to enable the encapsulated fuse to be thermally cycled between -40* and +150* without rupturing the bond between the casing and the epoxy resin.
Claim 4
Dependent Claim
36 words
An invention as defined in claim 2 wherein the body of epoxy resin is essentially homogenous and is formed to have a minimum thickness of 1/16 inch, in the direction of a radius Of said casing.
Claim 5
Dependent Claim
82 words
An invention as defined in claim 3 wherein the body of epoxy resin and said fluid-tight seals are effective to limit a flow of Helium gas therethrough to a rate no larger than 1 X 10 6 cubic centimeters per second of Helium gas when a pressure differential of approximately 14 pounds per square inch of surface area is established between the gases respectively adjacent the interior surface of said casing and the exterior surface of the body of encapsulating epoxy resin.
Claim 6
Dependent Claim
53 words
An invention as defined in claim 4 wherein said epoxy resin and fluid-tight seals are effective to limit a flow of Helium gas therethrough to a rate in the range of 1 X 10 6 and 1 X 10 6 cubic centimeters per second of Helium gas when the aforesaid pressure differential exists.
Claim 7
Dependent Claim
62 words
An invention as defined in claim 1 including an elongated core member mounted in said casing in spaced apart relationship with respect to the inner walls thereof, said at least one fusible link being spirally wound on said core member, said core member being formed of a dielectric material that does not evolve gas when heated to a temperature of 150* C.
Claim 8
Dependent Claim
55 words
An invention as defined in claim 6 including a body of granular dielectric filler material mounted in said casing around the core member, and including a pad of a resilient elastomeric material that is compressed between said first end cap and the filler material thereby to exert a continuous compressive force on said filler material.
Claim 9
Dependent Claim
37 words
An invention as defined in claim 1 wherein said means defining first and second bands of resilient elastomeric material comprise first and second bands of a thermally cured elastomer that are bonded to said end caps, respectively.
Claim 10
Dependent Claim
58 words
An invention as defined in claim 1 wherein said means defining first and second bands of resilient elastomeric material comprise a pair of annular gaskets, and including a pair of layers of epoxy cement, respectively positioned between each of said gaskets and their associated end caps, thereby to bond the gaskets to the end caps in fluid-tight relationship.
Claim 11
Dependent Claim
46 words
An invention as defined in claim 1 including wall means defining a passageway through said first end cap and said first terminal member, whereby gas may be vented from the interior of the casing to the exterior thereof, in combination with means for sealing said passageway.
Claim 12
Dependent Claim
30 words
An invention as defined in claim 10 wherein said means for sealing said passageway comprises a potting compound positioned in said passageway in fluid-tight relationship with the wall means thereof.
Claim 13
Dependent Claim
27 words
A invention as defined in claim 10 wherein said means for sealing said passageway comprises a body of solder having a melting point higher than 160* C.
Claim 14
Dependent Claim
38 words
An invention as defined in claim 11 wherein said means for sealing said passageway includes a plug disposed within the wall means of the passageway thereby to at least partially limit a flow of gas through the passageway.
Claim 15
Dependent Claim
21 words
An invention as defined in claim 13 wherein said plug comprises a metal screw that is threaded into said wall means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |