US3594677A

US3594677A - Retainer for blade-type electrical fuse clip

Info

Publication number: US3594677A
Application number: US12959A
Authority: US
Inventors: Frank A De Backer
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1970-02-20
Filing date: 1970-02-20
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20

Abstract

A connector clip for a blade-type electrical fuse has a steel bracket pivotally attached by a rivet passing through both legs of the clip near the closed end. The bracket has legs disposed closely adjacent the outer sides of the clip to prevent lateral distortion of the clip. A third bracket leg extends inside the clip to lie under the fuse blade and an arm of the bracket extends upward and over the fuse blade. Upon insertion of the fuse blade into the clip the blade engages the third leg to pivot the arm over the top of the blade. Outward movement of the blade is prevented by the overlying arm which must be manually pivoted out of the way to permit removal. No tool is required to either install or remove the fuse.

Description

United States Patent 5 Frank A. De Backer [72] Inventor Wichita, Kins.

[21] Appl. No. 12,959

[22] Filed Feb. 20, 1970 [45] Patented July 20, 1971 [73] Assignee Cutler-Hammer, Inc.

Milwaukee, Wis.

[54] RETAINER FOR BLADE-TYPE ELECTRICAL FUSE 2,984,723 5/1961 Jacobs 337/215 FOREIGN PATENTS 910,560 5/1954 Germany 337/211 Primary Examiner-Bemard A. Gilheany Assistant Examiner-F. E. Bell Attorney-Hugh R Rather ABSTRACT: A connector clip for a blade-type electrical fuse has a steel bracket pivotally attached by a rivet passing through both legs of the clip near the closed end. The bracket has legs disposed closely adjacent the outer sides of the clip to prevent lateral distortion of the clip. A third bracket leg extends inside the clip to lie under the fuse blade and an arm of the bracket extend! upward and over the fuse blade. Upon insertion of the fuse blade into the clip the blade engages the third leg to pivot the arm over the top of the blade. Outward movement of the blade is prevented by the overlying arm which must be manually pivoted out of the way to permit removal. No tool is required to either install or remove the fuse.

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RETAINER FOR BLADE-TYPE ELECTRICAL FUSE CLIP BACKGROUND OF THE INVENTION This invention relates to spring clip connectors for bladetype fuses and more particularly to a means on the spring clip for positively holding the fuse blade therein upon high current short circuit conditions or the like.

It is well known in the art of fused electrical safety and disconnect switches and similar apparatus that short circuit conditions create magnetic forces of sufficient magnitude to severely damage the devices. The forces tend to open the legs of the spring clip connectors which receive the fuse and switch blades, often bending the clip legs beyond the elastic limits of the material to permanently distort the legs. Other forces are created which tend to drive the blade outwardly of the clip in a direction nonnal to the forces moving the legs apart. Various devices and methods have been provided in the past for bolding the legs of spring clips together and for positively holding the blade between the clip legs. For the most part, these prior art devices have required the use of tools, a particular manipulation of parts in inserting the fuse or a need for separate parts to be assembled to the clip afterthe fuse is inserted. Such designs can be particularly cumbersome when employed in enclosed switch devices such as safety and disconnect switches.

SUMMARY OF THE INVENTION response to the insertion of a fuse blade therein to move to a position wherein it blocks outward movement of the blade from the clip.

It is a further object of this invention to provide a retainer bracket for a fuse clip or the like wherein the bracket automatically moves to an operative position to block removal of the fuse when the fuse is inserted and which has means surrounding the legs of the clip to positively limit the separation thereof.

These and other objects and advantages of the invention will become more apparent in the following specification and claims when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS 1 retainer bracket as shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings there is shown a fuse clip 2 formed of a strip of good electrically conducting material such as copper or the like. The fuse clip 2 is formed by doubling over the strip to form a base and then forming the ends of the strip upwardly at substantially right angles to the base portion to form the pair of clip legs 2b. The ends of legs 21: are flared outwardly to facilitate insertion of a fuse blade or the like therebetween.

The material from which the clip 2 is formed is chosen primarily for its current-carrying characteristics and not for its spring pressure qualities. Therefore, to improve the latter a backup spring 4 of pring steel or the like is provided around the clip 2 to bear upon the upper ends of legs 2b and provide additional spring pressure for the clip. The backup spring 4 bridges the space between the legs 21; of the clip within slots formed in the edges of the legs near the base portion to avoid interference with the fuse blade.

Fuse clip 2 is attached to an electrical connector strip 6 by a pair of screws 8 which pass through clearance holes in the base portion 2a to take into aligned tapped openings provided in the connector strip 6. The latter is in turn secured upon an insulating base 10, such as the base of a safety switch or similar device, by a bolt 12 which extends upward through aligned openings in the base 10, connector strip 6 and a solderless connector lug 14 to receive a lockwasher and not 16 thereon for securing the parts.

The fuse clip assembly is further provided with a retainer bracket 18 which is formed from a sheet of high strength steel or the like. Retainer bracket 18 has a pair of outer legs 18a extending from a main body portion 18b and a third leg 18c formed from a depending portion of one of the outer legs 18a to extend parallel to and centrally of the outer legs from a point directly below the main body portion 18b. The leg 18c has a dome-shaped free end which serves as a camming surface as will be specifically described hereinafter. The main body portion 18b extends above the upper edges of outer legs 18a and is formed over at right angles at the end to provide an overhanging arm 18d for the bracket.

Retainer bracket 18 is permanently attached to the fuse clip 2 by a rivet 20 which passes through aligned holes'formed in the third leg 18c and the particular outer leg 18a from which the central leg is supported and aligned. holes in the lower portions of legs 2b of fuse clip 2. The retainer bracket 18 is free to pivot upon the rivet 20 and is normally rocked to the position shown in FIG. 3 when no fuse is inserted in the clip.-As can be seen from the drawings, the central leg extends between the fuse clip legs 2b while the outer legs 18a lie closely adjacent the external surfaces of fuse clip legs 2b to positively limit the outward movement of the fuse clip legs, thereby preventing distortion thereof.

One end of a cartridge type fuse 22 having a blade terminal 24 isshown in the drawings. In FIG. 3 the fuse 22 is shown aligned in position at the outer end of the fuse clip 2 preparatory to being inserted therein. Movement of the fuse blade 24 into the clip causes the lower edge of the blade 24 to engage the domed camming surface at the free end of third leg 18c. Continued inward movement of the blade pivots the retainer bracket 18 about the rivet 20 to cause the arm 18d to move over the top of the clip 2 and the upper edge of the blade 24 as shown in FIG. 1.

With the fuse 22 so inserted in the fuse clip 2, direct removal thereof is impossible without first pivoting the retainer bracket 18 to move arm 18d clear of the fuse blade 24. The length of the arm 18d overlying the blade is chosen to be substantially equally disposed on either side of a line extending normal to the arm 18d and passing through the pivot point of the bracket 18. The forces created upon the arm 18d by outward movement of the fuse blade 24 from the fuse clip 2 are equally disposed about the pivot point and are statically reduced to a single force extending through the pivot point of the bracket 18 to produce a zero moment for the bracket.

While a single preferred embodiment has been disclosed herein it is to be understood that the retainer bracket of this invention is susceptible to modification without departing from the scope of the appended claims.

I claim:

1. An electrical fuse clip and retainer bracket assembly comprising, in combination:

a spring clip electrical connector having a pair of substantially parallel upstanding legs for receiving a fuse blade therebetween;

a bracket member pivotally mounted to said spring clip to move about an axis normal to the plane of said upstanding said upstanding legs and an arm portion extending in the same general direction as said leg portion and outwardly spaced from said leg portion, and

' wherein the lower edge of a fuse blade engages-said leg portion upon insertion of said blade into said clip to pivot said bracket upon said clip, thereby moving said arm portion to a position over the upper edge of said fuse blade and in outward alignment with the pivotal axis of said bracket to interfere with and prevent the direct removal of said fuse blade from said spring clip connector.

2. The combination according to claim 1 wherein the i pivotal axis for said bracket extends through said leg portion of said bracket and through the upstanding legs of said spring clip connector.

3. The combination according to claim 2 wherein engagement of said blade with said arm portion upon outward movement of said blade occurs over an area substantially equally disposed about an imaginary line extending parallel to the direction of movement of said blade and through the pivotal axis of said bracket to effect a zero moment for said bracket.

4. The combination according to claim 2 wherein said retainer bracket includes a pair of leg portions disposed on opposite sides of the first-mentioned leg portion and extending along the respective external surfaces of said upstanding legs of said spring clip connector, thereby limiting the lateral movement of said upstanding legs.

4 An electrical fuse clip assembly comprising, in combination: 7

an electrical spring clip connector having a pair of upstanding legs for receiving a fuse blade therebetween;

a' bracket member pivotally mounted to said spring clip connector to move about an axis normal to the plane of said upstanding legs, said bracket member including:

a pair of legs along the outer surfaces of said upstanding legs of said spring clip connector, said pair of legs of said bracket limiting the lateral movement of said upstanding legs of said spring clip connector;

a third'leg disposed between said upstanding legs of said spring clip connector; and

an arm portion extendingin' the same general direction as said third leg and spaced therefrom by an amount sufficient to permit movement of said arm over the ends of said upstanding legs of said spring clip connector; and

wherein the lower edge of a fuse blade engages the end of said third leg upon insertion of said blade into said clip to pivot said bracket, thereby moving said arm over the ends of said upstanding legs and over the upper edge of said fuse blade to a position in outward alignment with the pivotal axis of said bracket to interfere with said fuse blade and prevent the direct removal of said blade from said spring clip connector.

Claims

1. An electrical fuse clip and retainer bracket assembly comprising, in combination: a spring clip electrical connector having a pair of substantially parallel upstanding legs for receiving a fuse blade therebetween; a bracket member pivotally mounted to said spring clip to move about an axis normal to the plane of said upstanding legs, said bracket having a leg portion disposed between said upstanding legs and an arm portion extending in the same general direction as said leg portion and outwardly spaced from said leg portion, and wherein the lower edge of a fuse blade engages said leg portion upon insertion of said blade into said clip to pivot said bracket upon said clip, thereby moving said arm portion to a position over the upper edge of said fuse blade and in outward alignment with the pivotal axis of said bracket to interfere with and prevent the direct removal of said fuse blade from said spring clip connector.

2. The combination according to claim 1 wherein the pivotal axis for said bracket extends through said leg portion of said bracket and through the upstanding legs of said spring clip connector.

5. An electrical fuse clip assembly comprising, in combination: an electrical spring clip connector having a pair of upstanding legs for receiving a fuse blade therebetween; a bracket member pivotally mounted to said spring clip connector to move about an axis normal to the plane of said upstanding legs, said bracket member including: a pair of legs along the outer surfaces of said upstanding legs of said spring clip connector, said pair of legs of said bracket limiting the lateral movement of said upstanding legs of said spring clip connector; a third leg disposed between said upstanding legs of said spring clip connector; and an arm portion extending in the same general direction as said third leg and spaced therefrom by an amount sufficient to permit movement of said arm over the ends of said upstanding legs of said spring clip connector; and wherein the lower edge of a fuse blade engages the end of said third leg upon insertion of said blade into said clip to pivot said bracket, thereby moving said arm over the ends of said upstanding legs and over the upper edge of said fuse blade to a position in outward alignment with the pivotal axis of said bracket to interfere with said fuse blade and prevent the direct removal of said blade from said spring clip connector.