Patent US3849755A successfully refreshed from Google Patents.
US3849755A
Expired / Lapsed
US
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Current limiting fuse with fuse element with a diamond shaped cutout
Assignee: Westinghouse Electric Corp
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Filing: 1973-09-28
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Granted: 1974-11-19
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Expires: 1993-09-28
Abstract
Abstract An electrical current limiting fuse of the type having fuse elements disposed in a pulverulent arc quenching material for melting after a predetermined level of current has been attained and sustained for a predetermined period of time. A fuse element of the current limiting fuse is in a form of an elongated ribbon of fuse material having a diamond shaped central opening. The diamond shaped central opening provides a pair of parallel current paths near either side of the fuse element. The diamond shaped element has two oppositely disposed angles of approximately 37 1/2 degrees approximately either side edge of the fuse material.
Inventors
- 👤 D Blewitt
- 👤 W Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:35
CPC Classifications
H; H01; H01H; H01H85/00; H01H85/02; H01H85/04; H01H85/05; H01H85/055
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
204 words
An electrical fuse, comprising: a. a tubular casing of electrical insulating material; b. spaced terminals disposed adjacent portions of said casing; and c. a fuse element of electrically conductive material disposed within said casing and electrically connected to said spaced terminals for interrupting electrical current flowing through said fuse when said current is of a predetermined value, said electrically conductive material having a central opening therein, said central opening enclosing as one part of the periphery thereof an angle substantially in the range of 30* to 45*, said angle having an apex which is spaced from one surface of said electrically conductive material by a predetermined distance to thereby provide an electrically resistive region of reduced cross section, the bisector of said angle being perpendicular to said one surface within a predetermined range, the radius of curvature of said apex of said angle being smaller than said distance between said apex and said one surface by a predetermined amount to thereby reduce the electrical resistance of said conductive material adjacent said region of reduced cross section, the length of at least one peripheral side of said angle being larger by a predetermined amount than said predetermined distance between said apex and said one side.
Claim 2
Dependent Claim
204 words
An electrical fuse, comprising: a. a tubular casing of electrical insulating material; b. spaced terminals disposed adjacent portions of said casing; and c. a fuse element of electrically conductive material disposed within said casing and electrically connected to said spaced terminals for interrupting electrical current flowing through said fuse when said current is of a predetermined value, said electrically conductive material having a central opening therein, said central opening enclosing as one part of the periphery thereof an angle substantially in the range of 30* to 45*, said angle having an apex which is spaced from one surface of said electrically conductive material by a predetermined distance to thereby provide an electrically resistive region of reduced cross section, the bisector of said angle being perpendicular to said one surface within a predetermined range, the radius of curvature of said apex of said angle being smaller than said distance between said apex and said one surface by a predetermined amount to thereby reduce the electrical resistance of said conductive material adjacent said region of reduced cross section, the length of at least one peripheral side of said angle being larger by a predetermined amount than said predetermined distance between said apex and said one side.
Claim 3
Dependent Claim
246 words
An electrical current limiting fuse, comprising: a. a tubular casing of electrical insulating material; b. spaced terminals disposed adjacent portions of said casing; c. pulverulent arc quenching material disposed within said tubular casing; and d. a fuse element of electrically conductive material disposed within said casing and electrically connected to said spaced terminals for interrupting electrical current flowing through said fuse when said current is of a predetermined value, said electrically conductive material having a central opening therein, said central opening enclosing as one part of the periphery thereof an angle substantially in the range of 30* to 45*, said angle having an apex which is spaced from one surface of said electrically conductive material by a predetermined distance to thereby provide an electrically resistive region of reduced cross section which melts in the presence of said predetermined value of electrical current, the bisector of said angle being perpendicular to said one surface within a predetermined range, an electrical arc being produced for limiting said current, said arc quenching material assisting in quenching said arc, the radius of curvature of said apex of said angle being smaller than Said distance between said apex and said one surface by a predetermined amount to thereby reduce the electrical resistance of said conductive material adjacent said region of reduced cross section, the length of at least one peripheral side of said angle being larger by a predetermined amount than said predetermined distance between said apex and said one side.
Claim 4
Dependent Claim
246 words
An electrical current limiting fuse, comprising: a. a tubular casing of electrical insulating material; b. spaced terminals disposed adjacent portions of said casing; c. pulverulent arc quenching material disposed within said tubular casing; and d. a fuse element of electrically conductive material disposed within said casing and electrically connected to said spaced terminals for interrupting electrical current flowing through said fuse when said current is of a predetermined value, said electrically conductive material having a central opening therein, said central opening enclosing as one part of the periphery thereof an angle substantially in the range of 30* to 45*, said angle having an apex which is spaced from one surface of said electrically conductive material by a predetermined distance to thereby provide an electrically resistive region of reduced cross section which melts in the presence of said predetermined value of electrical current, the bisector of said angle being perpendicular to said one surface within a predetermined range, an electrical arc being produced for limiting said current, said arc quenching material assisting in quenching said arc, the radius of curvature of said apex of said angle being smaller than Said distance between said apex and said one surface by a predetermined amount to thereby reduce the electrical resistance of said conductive material adjacent said region of reduced cross section, the length of at least one peripheral side of said angle being larger by a predetermined amount than said predetermined distance between said apex and said one side.
Claim 5
Dependent Claim
19 words
The combination as claimed in claim 2 wherein said central opening is substantially in the shape of a parallelogram.
Claim 6
Dependent Claim
13 words
The combination as claimed in claim 2 wherein said angle is substantially 37.5*.
Claim 7
Dependent Claim
27 words
The combination as claimed in claim 2 wherein said predetermined distance is equal to or larger than approximately 5 times the radius of curvature of said apex.
Claim 8
Dependent Claim
21 words
The combination as claimed in claim 2 wherein said bisector of said angle is perpendicular to said one surface within 4*.
Claim 9
Dependent Claim
38 words
The combination as claimed in claim 2 wherein the length of said at least one peripheral side of said angle is equal to or larger than approximately 9.5 times the distance between said apex and said one surface.
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) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |