HIGH VOLTAGE FUSE HAVING HELICALLY WOUND RIBBON FUSE LINK
First Claim
Patent Images
1. A current-limiting high-voltage fuse including:
- a. a ribbon of relatively hard resilient sheet silver of rectangular cross section having a plurality of serially related points of reduced cross-sectional area wound helically with the wide side thereof parallel to an axis to form an extension-springlike structure, said extension-springlike structure having a diameter ranging from about three-sixteenths of an inch to less than one-half of an inch and having when in unloaded condition a spacing between contiguous windings thereof of substantially less than said diameter, said extension-springlike structure being axially stretched to such a degree that the deflection per turn exceeds said diameter resulting in an extension to a predetermined length, said extension-springlike structure having overcenter ends at the ends of the helical portion thereof;
b. receptacle means defining a cylindrical passage having said predetermined length and an inner diameter ranging from less than about three times to about four times said diameter of said extension-springlike structure, said extension-springlike structure being arranged inside said passage in coaxial relation thereto and said overcenter ends of said extensionspringlike structure being substantially coextensive with the axis of saId passage;
c. a pair of terminal elements arranged at the ends of said passage each conductively connected to one of said overcenter ends of said extension-springlike structure; and
d. compacted pulverulent arc-quenching filler means inside said passage submersing said extension-springlike structure, said filler means being the only lateral support of said extensionspringlike structure between said pair of terminal elements of said fuse.
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Abstract
A high-voltage fuse having a helically wound ribbon fuse link forming an extension-springlike structure. The ribbon fuse link is entirely self-supporting, not requiring any support between the ends thereof other than a pulverulent arc-quenching filler.
6 Citations
7 Claims
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1. A current-limiting high-voltage fuse including:
- a. a ribbon of relatively hard resilient sheet silver of rectangular cross section having a plurality of serially related points of reduced cross-sectional area wound helically with the wide side thereof parallel to an axis to form an extension-springlike structure, said extension-springlike structure having a diameter ranging from about three-sixteenths of an inch to less than one-half of an inch and having when in unloaded condition a spacing between contiguous windings thereof of substantially less than said diameter, said extension-springlike structure being axially stretched to such a degree that the deflection per turn exceeds said diameter resulting in an extension to a predetermined length, said extension-springlike structure having overcenter ends at the ends of the helical portion thereof;
b. receptacle means defining a cylindrical passage having said predetermined length and an inner diameter ranging from less than about three times to about four times said diameter of said extension-springlike structure, said extension-springlike structure being arranged inside said passage in coaxial relation thereto and said overcenter ends of said extensionspringlike structure being substantially coextensive with the axis of saId passage;
c. a pair of terminal elements arranged at the ends of said passage each conductively connected to one of said overcenter ends of said extension-springlike structure; and
d. compacted pulverulent arc-quenching filler means inside said passage submersing said extension-springlike structure, said filler means being the only lateral support of said extensionspringlike structure between said pair of terminal elements of said fuse.
- a. a ribbon of relatively hard resilient sheet silver of rectangular cross section having a plurality of serially related points of reduced cross-sectional area wound helically with the wide side thereof parallel to an axis to form an extension-springlike structure, said extension-springlike structure having a diameter ranging from about three-sixteenths of an inch to less than one-half of an inch and having when in unloaded condition a spacing between contiguous windings thereof of substantially less than said diameter, said extension-springlike structure being axially stretched to such a degree that the deflection per turn exceeds said diameter resulting in an extension to a predetermined length, said extension-springlike structure having overcenter ends at the ends of the helical portion thereof;
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2. A current-limiting high-voltage fuse as specified in claim 1 wherein said spacing in unloaded condition between contiguous turns ranges from near zero to about one thirty-second of an inch.
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3. A current-limiting high-voltage fuse as specified in claim 1 wherein said deflection per turn of said extension-springlike structure is about twice the radius thereof.
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4. A current-limiting fuse as specified in claim 1 wherein said plurality of serially related points of reduced cross-sectional area of said ribbon is formed by serially related circular perforations arranged along the center of said ribbon and wherein the longitudinal edges of said ribbon are unnotched.
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5. A current-limiting fuse as specified in claim 1 wherein said pulverulent arc-quenching filler consists of a relatively long layer of quartz sand and a relatively short layer including a mixture of silica and oxides of aluminum and iron with a content of about 50 percent of silica and about 20 percent of said oxides, and wherein said extension-springlike structure has a link-severing overlay of a metal having a lower fusing point than silver at a point thereof submersed in said relatively short layer of filler.
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6. A current-limiting high-voltage fuse including:
- a. a tubular main casing of insulating material having a relatively large diameter;
b. a pair of terminal plugs closing said main casing at the ends thereof, each of said terminal plugs having registering cylindrical recesses at the axially inner and surfaces thereof;
c. a plurality of tubular subcasings having a predetermined length and closed at the ends thereof by terminal caps projecting into said recesses of said pair of terminal plugs, each of said plurality of subcasings having a smaller inner diameter than said main casing, said smaller inner diameter ranging from about one-half of an inch to less than 2 inches;
d. a plurality of extension-springlike structures each formed of a ribbon of relatively hard silver of rectangular cross section having a plurality of serially related circular perforations wound helically with the wide side thereof parallel to an axis to form one of said plurality of extension-springlike structures, each of said plurality of extension-springlike structures having a diameter ranging from about three-sixteenths of an inch to less than one-half of an inch and having when in unloaded condition a length substantially less than said predetermined length of each of said plurality of subcasings, each of said plurality of extension-springlike structures being axially stretched to such a degree that the deflection per turn is in the order of twice said diameter and results in an elongation of each of said plurality of extension-springlike structures to equal substantially said predetermined length of each of said plurality of subcasings, each of said extension-springlike structures having overcenter ends at the ends of the helical portion thereof and being arranged inside one of said plurality of subcasings in coaxial relation thereto, said overcenter ends of each of said plurality of extension-springlike structures being threaded through perforations in the end surfaces of said terminal caps of one of said plurality of subcasings and conductively interconnecting said terminal caps; and
e. compacted pulverulent arc-quenching filler means inside each of said plurality of subcasings, said filler means being the only lateral support of each of said plurality of extension-springlike structures between said terminal caps of each of said pluralitY of subcasings.
- a. a tubular main casing of insulating material having a relatively large diameter;
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7. A current-limiting high-voltage fuse including:
- a. a tubular main casing of insulating material having a relatively large diameter;
b. a pair of terminal elements closing said main casing at the ends thereof;
c. a cylindrical block of a ceramic insulating material arranged inside of and in coaxial relation to said main casing between the axially inner end surfaces of said pair of terminal elements, said block having a plurality of axially extending bores, each of said plurality of bores having a predetermined length and a diameter ranging from about one-half of an inch to 2 inches;
d. a plurality of extension-springlike structures each formed of a ribbon of relatively hard silver rectangular in cross section having a plurality of serially related circular perforations would helically with the wide side thereof parallel to an axis to form one of said plurality of extension-springlike structures, each of said extension-springlike structures having a diameter ranging from about three-sixteenths of an inch to less than one-half of an inch and having when in unloaded condition a length substantially less than said predetermined length of said plurality of bores of said cylindrical block, each of said plurality of extension-springlike structures being axially stretched to such a degree that the deflection per turn is in the order of twice said diameter of each of said plurality of extension-springlike structures to equal substantially said predetermined length of each of said plurality of bores, each of said extension-springlike structures having overcenter ends at the end of the helical portion thereof and being arranged inside of one of said plurality of bores in coaxial relation thereto, said overcenter ends of each of said plurality of extension-springlike structures being conductively connected to said pair of terminal elements; and
e. compacted pulverulent arc-quenching filler means inside each of said plurality of bores of said cylindrical block, said filler means being the only lateral support of each of said plurality of extension-springlike structures throughout said predetermined length of each of said plurality of bores of said cylindrical block.
- a. a tubular main casing of insulating material having a relatively large diameter;
Specification