US3896408A - Fuse ejector - Google Patents

Abstract

A combination fuse ejector and protective shroud for cartridge type fuses includes a molded plastic receptacle having protective peripheral walls, an open top and a partially open bottom. The partially open bottom includes an opening adjacent each end through which the usual fuse holding contact clips protrude. A bridge portion across the bottom includes a holding pedestal which provides a loosely coupled captive mounting for the shroud. The bridge portion across the bottom of the shroud also includes a fuse-ejecting abutment adjacent one of the pair of contact clips whereby one end of the fuse may be ejected from that adjacent clip by the lifting of the shroud on its loosely captive pedestal.

Description

United States Patent [191 'Leidy, Jr.

[ July 22, 1975 I541 FUSE EJECTOR [75] Inventor: Lester R. Leidy, Jr., Oreland, Pa.

[73] Assignee: Honeywell Inc., Minneapolis, Minn.

[22] Filed: Jan. 31, 1974 [21] Appl. No.: 438,370

[52] US. Cl. 337/211; 339/45 R [51] Int. Cl. H01H 85/22; l-IOll-I 85/54 [58] Field of Search, 339/45 R, 45 M, 46;

[56] References Cited UNITED STATES PATENTS Primary Examiner.loseph I-I. McGlynn Assistant Examiner-Craig R. Feinberg Attorney, Agent, or FirmArthur H. Swanson; Lockwood D. Burton; John Shaw Stevenson [5 7 ABSTRACT A combination fuse ejector and protective shroud for cartridge type fuses includes a molded plastic receptacle having protective peripheral walls, an open top and a partially open bottom. The partially open bottom includes an opening adjacent each end through which the usual fuse holding contact clips protrude. A bridge portion across the bottom includes a holding pedestal which provides a loosely coupled captive mounting for the shroud. The bridge portion across the bottom of the shroud also includes a fuse-ejecting abutment adjacent one of the pair of contact clips whereby one end of the fuse may be ejected from that adjacent clip by the lifting of the shroud on its loosely captive pedestal,

5 Claims, 5 Drawing Figures FUSE EJECTOR CROSS REFERENCE TO RELATED APPLICATIONS Subject matter shown and described but not claimed herein is shown, described and claimed in a copending application of Ralph M. Levy Ser. No. 438,369 filed on even date herewith.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an improved Fuse Ejector of the type generally classified in the United States Patent Office with Tools, Special, Fuse Pullers.

2. Description of the Prior Art Many different types of devices have been proposed in the prior art for inserting cartridge type fuses into and/or ejecting such fuses from conventional spring clip mounted in fixed spaced apart relationship on a support place, such as a PC board. One such device employes a dedicated plastic tool having finger gripping portions at one end and a C-shaped fuse holder at its other end. Such tool must first be forced over an end of the fuse to a center portion. The fuse may then be mounted in the customary manner between spaced spring clips by gripping the tool and forcing the ends of the fuse into support relationship with the spring clip. In order to remove the fuse from its clips a pulling force may be applied by grasping the tool and pulling. Such a tool is, at best, inconvenient to use. Because of slippage between the tool and the fuse difficulty has been experienced, moreover, in inserting the fuse properly between the spaced clip contacts.

Additionally, there is a possibility with unshrouded or unprotected fuse holders for one servicing equipment to experience a shock when a fuse is inserted or removed because of the exposed electrical contacting surfaces.

For providing a protective shroud, it has been proposed in the prior art to provide a non-conductive U- shaped shell, the base portion of which is mounted rigidly on the associated mounting base. The sides of the shell extend away from the base coextensively with the spring clips. Centrally located slots formed in the sides of the shell enable one servicing the equipment to grasp the central portion of the fuse when it is desired to insert or remove a fuse from the clip contacts.

Since both ends, and parts of each of the sides of the shell are open, there is a possibility that an'electrical shock will be received when the fuse is inserted or removed from the spring clips. There is also the possibility that the fuse will be damaged by a mechanical tool such as a screwdriver which is often used by one servicing the equipment, in lieu of a proper tool, to force the fuse into or out of its clip engaging position. Significant force is required to remove cartridge type fuses from the clips retaining them, in consequence of which the fuses sometimes pop out and fly into the face of the person employing an improper tool such as a screwdriver to remove them.

There are other fuse pullers which do not have a tendency to pop the fuse out. They are in the form of a fiber board pliers with which to grip the fuse andremove or insert it with respect to the clips.

The difficulty with such devices is the usual lethargy of the service person. The tool must be handy when it is desired to change fuses; otherwise, one servicing LII equipment will use whatever device is at hand even though not designed for fuse ejection.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a shroud/ejector having openings in a base portion through which fuse retaining spring clips are adapted to extend. The shroud is mounted for limited movement toward and away from the PC board or other support base on which the spring clips are mounted by means of a retaining pedestal that extends away from the base of the shroud and through an opening in the board. For loosely retaining the shroud/ejector on the board, resilient shoulders or other suitable stop means are provided on the remote end of the pedestal. The said stop means are of larger size than the opening in the board receiving the pedestal.

Tongues are formed on inner end wall portions of the shroud/ejector to guide the ends of the fuse into proper position with respect to the spaced spring clips. When so positioned the cartridge fuse is held in proper position to be engaged by a concave surface formed on a bridge portion formed on the bottom of the shroud/ejector. This concave surface is closer to one end of the shroud/ejector than the other.

Ejection of the fuse from its position between the spring clips is accomplished by pulling the loosely mounted shroud/ejector away from the support base. Such pulling causes the concave surface on the bridge to lift one end of the fuse out of its retaining clip. The lifted end of the fuse may then be safely grasped and be readily removed.

The aforementioned fuse ejection shroud therefore provides a better means for protecting a fuse from mechanical damage when it is mounted therein than prior art fuse pullers. The ejector/shroud also provides a means by which the fuse can be moved to an ejected position without the need of an ancillary fuse ejecting tool. Such tools, dedicated or not, have disadvantages, as has been noted.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the present invention may be had when the following detailed description is read in connection with the accompanying drawings in which:

FIG. 1 is a plan view of the fuse ejector/shroud embodying the present invention;

FIG. 2 is a sectional elevation view taken along the line 2--2 of FIG. 1;

FIG. 3 is a bottom view of the fuse ejector/shroud;

FIG. 4 shows an external view of a self-anchoring tube and a portion of the shroud to which it is attached before these unitary parts are mounted on the support plate and; j

FIG. 5 shows the anchoring tube being compressed for insertion into an opening in a support base.

DESCRIPTION OF THE PREFERRED EMBODIMENT DETAILED DESCRIPTION Referring to FIGS. 1, 2, and 3 in more detail, there is shown a unitary fuse ejector/shroud 10 which is comprised of two major parts, namely, a shroud l2 and a self-anchoring tube 14. The unitary fuse ejector 10 is molded of a suitable electrical insulating plastic mate- .rial having semi-resilient characteristics, as for example a suitable polypropylene material or nylon.

The shroud 12 is of a rectangular box shaped configuration and has a pair of walls 16, 18 forming the end portions of the box, a pair of elongated walls 20, 22 forming the sides of the box and a bridge portion 24 which form a base of the box shaped shroud 12.

The bridge portion 24 of the shroud 12 has a pair of spaced apart openings 26, 28 therein. Each of the openings 26, 28 are shown positioned about a different one of a pair of U-shaped spring clip contacts 30, 32 which are, in turn, shown in phantom mounted in a fixed position on a support board 34.

The spring clip contacts 30, 32 which are surrounded by the shroud 12 are of a well known type. These clip contacts 30, 32 are shown having a pair of end stops 36, 38; 40, 42 at each of their outer end portions. The base of each of the clip contacts 30, 32 is attached by a rivet 44, 46 to the support board 34.

The shroud 12 has a pair of fuse guide surfaces or tongues 48, 50 extending in an inward direction from its end wall 16, 18. The upper ends of each of these tongues 48, 50 have a beveled surface 52, 54. A cartridge type fuse 56 is shown in phantom in FIG. I, having its respective conductive ends 58, 60 held between the associated spring clip contacts 30, 32. The fuse 56 is shown extending between and in spaced relation with the top of the tongues 48, 50. These tongues are positioned to extend between the end stops 36, 38; 40, 42 formed on the associated spring clip contacts 30, 32.

The bridge portion 24 of the shroud 12 has rib portions 62 and 64, extending, respectively, inwardly from the elongated sides thereof, and a transverse abutment portion 66 interconnecting one end of the rib portions 62, 64.

A concave or arcuate shaped surface 68 is formed in the transverse bridge portion 66 the radius of curvature of which is larger than that of the transparent part of the fuse 56. In FIGS. 1 and 2, there is shown a lower left transparent end portion of the fuse 56 substantially in'engagement with longitudinal portion of the concave surface 68 when the fuse 56 is mounted in the clips 30,

32. In FIG. 2, there is shown in solid line form, the position that the shroud 12 and anchoring tube 14 is in when it is mounted on the support board 34. In this latter mentioned figure there is also shown the fuse 56 having itsend portions 58, 60 retained in the U-shaped clips 30, 32 and a transparent part of the fuse 56 substantially in engagement with the base portion 24 of the shroud l2 and tending to hold the shroud in loose en- I gagement against the support board 34.

There is further shown, in FIG. 2, in dash line form the position that the shroud 12 and anchoring tube 14 is in when the shroud 12 has been lifted away from the support board 34 to a position where the left end 58 of the fuse 56 has been ejected from its associated clip 30.

In FIG. 2, it is also shown that a point 70 on the right lower most portion of the concave surface 68 is the only part of the base plate 24 that is engaged with the fuse 56 when the shroud 12 is in its fullylifted fuse ejected position such as is shown in dash line form in FIG. 2.

The shroud 12 is shown in FIG. '2 as having a slanted surface 72 extending between the rib portions 62, 64

surface 72 is shown in spaced relation to the fuse 56 when the fuse 56 is in either its horizontal or in its tilted position as is shown in FIG. 2.

As is best shown in FIGS. 1 and 2, the slanted surface 72 forms the upper end of the previously mentioned self anchoring tube 14. As shown in FIGS. 4 and 5, the upper portion 78 of the tube 14 is of substantially cylindrical configuration. In FIG. 3, the lower portion 80 of the tube 14 is shown as being of a substantially elliptical shaped configuration. A pair of lugs 82, 84 having associated beveled edges 86, 88 are shown integral with the lower end of the tube 14 and extending away from one another along the major axis of the elliptical shaped portion 80. i

The lower or elliptical portion 80 of the tube 14, including the lugs 82, 84, may be compressed, as illustrated in FIG. 5, for example, by the jaws 90, 92 of a pair of pliers. Such compression of the lower end 80 of the tube 14 permits that end to be inserted through an opening 104 in the support board 34. Release of the compression after the end of the tube 14 has been inserted through the opening 104 allows that end of the tube to resume its initial configuration. The lugs 82, 84 then extend beyond the edge of the opening 104 whereby the tube 14 with its lugs 82, 84 constitute a loosely coupled captive mounting for the extractor 10.

MODE OF OPERATION The fuse ejector 10 is mounted on a support board 34 by first employing the free elliptical shaped end 80 of the self-anchoring tube 14 to cover the aperture 104 formed on the board 34 while the end of this tube 14 is in its non-compressed state as is shown in FIG. 4. As is best shown in FIG. 5 a pair of pliers or the like is then employed to compress the lugs 82, 84 and the end of the elliptical portion 80 of the tube 14, toward one another. While the lugs 82, 84 are thus compressed a sufficient amount to allow them to be inserted through the opening in the support board 34, a force is applied in the direction of the arrow 94 to the top surfaces of the walls 16, 18 of the shroud 12.

After the lugs 82, 84 have been inserted through the opening 104 in the support plate 34,-the natural resilient nature of the material of which the lugs 82, 84 and the tube 14 are made will allow these parts to resume the position they were in before they were compressed 'and therefore into the shroud retaining position as is shown in FIG. 2.

While the tube 14 is being moved through the support board 34 as just described, the openings formed by walls 26, 28 in the base 24 of the shroud 12 will allow the shroud 12 to be inserted over the U shaped spring clips 30, 32 and to be brought into loose captive mounting relationship with respect to the support board 34, as is shown in FIG. 2.

As the fuse 56 is inserted into the space formed by the walls 16, 22 of the shroud 12 the chamfered ends 52, 54 of the shroud 12 will guide end surfaces 58, 60 of fuse 56 into correct alignment with the ridges 48, 50 of the shroud 12.

The ridges 48, 50 thus provide guide surfaces for the end portions 58, 60 of a fuse 56 while the fuse 56 is and sloping in a left to right downward direction from the right end of the concave surface 68. This sloping being inserted through the open top portion of the shroud 12 whereby these end portions can be easily inserted in a desired position between the clips 30, 32. A glass central portion of the fuse will be substantially in line contact with the concave surface 68 formed on the inner base part 26 of the shroud 12.

To eject the fuse 56 from its position between the spring clips 30, 32, it is merely necessary to grasp the ends or side portions 96, 98; 100, 102 and to then pull the shroud 12 in a direction away from the support board 34.

The concave lifting surface 68 of the bridge portion 66 of the shroud 12 is positioned closer to the left end (as illustrated) of the fuse 56 than to its right end. The

concave portion 68 of the shroud 12 will as the shroud is lifted exert a force against the left end of the fuse 56 causing the left end of the fuse 56 to be forced from its position in which it is clamped by the spring clip 30, to a tilted position in which it is in point contact with a right end portion 70 of the concave surface 68 and completely disengaged from the spring clip 30.

Ejecting only one end of the fuse 56 in the aforementioned manner thus allows the concave surface 68 of the shroud 12 and then the right end point 70 of the surface 68 in sequence, to apply a small diminishing force to the lower surface of the fuse as the fuse 56 is ejected, obviating the tendency of the fuse to popout of the fuse holder, out of control.

Employing a shroud of the aforementioned type to eject the fuse in the aforementioned manner therefore eliminates the need for the use of any ancillary tool, such as a screwdriver such as has heretofore been improperly used with prior art fuse ejecting devices to pop these fuses out of their associated clips. Since no fuse popping action occurs' in the use of the fuse ejecting shroud 12, the danger of an operator being hit in the face with a fuse that has been shattered or popped out of its clips by means of a screwdriver is eliminated.

When the left portion of the fuse 56 has been moved to a tilted position in which it is free of its clip 30, the other end of the fuse 56 can then be readily removed from its position in the clip 32 by returning the shroud 12 to its position in contact with the support board 34, then grasping the portion of the fuse that is near its free upper left end, and applying a slight pulling force thereto.

Thus it may be seen that there has been provided an improved combination fuse ejector and protective shroud wherein no ancillary tool is required for removing a fuse from its spring clip mounting, and wherein injury to an attendant is avoided and protection for the tion with a pair of spaced spring clip contacts for a cartridge type fuse, said clip contacts being mounted on a suitable support base, said member comprising:

a non-conductive shroud body member of a single piece construction and of a substantially rectangular configuration having side and end walls of sufficient height to be at least coextensive with the spring clip contacts;

said shroud body member having a partially open bottom with an integral bridging portion extending transversely between said side walls, said bridging portion and said side and end walls defining a pair of openings through which said clip contacts are adapted to extend;

said bridging portion including a fuse engaging surface, a mounting pedestal integral with said bridging portion and extending in a direction opposite from the direction of the extension of said side walls and adapted to be inserted through a suitable opening in the support base, and

mounting means for loosely securing said pedestal in said opening, said pedestal being of a suitable length to provide a loosely captive mounting of said ejector/shroud member with respect to said support base, whereby to permit a cartridge fuse to be inserted between said clip contacts when said ejector/shroud member is fully-seated on said support base and whereby said fuse engaging portion of said bridging portion is operative to eject said mounted fuse from between said clip contacts when said shroud is lifted slightly from said support base.

2. A fuse ejector/shroud member as set forth in claim 1 wherein said shroud member is formed of a molded semi-resilient plastic material.

3. A fuse ejector/shroud member as set forth in claim 2 wherein said fuse engaging surface of said bridging portion includes a fuse ejecting abutment adjacent one of said openings through which said clip contacts extend whereby one end of said fuse is ejected from the associated clip contact by the lifting of said shroud/ejector from said support base on its loosely captive pedestal.

4. A fuse ejector/shroud member as set forth in claim 3 wherein said abutment includes a concave surface for engagement with said fuse.

5. A fuse ejector/shroud member as set forth in claim 2 and characterized by the inclusion of guide tongues formed on the inner surface of each of said end walls to guide the ends of said fuse into longitudinal position relative to said clip contacts.

Claims (5)

1. A fuse ejector/shroud member for use in association with a pair of spaced spring clip contacts for a cartridge type fuse, said clip contacts being mounted on a suitable support base, said member comprising: a non-conductive shroud body member of a single piece construction and of a substantially rectangular configuration having side and end walls of sufficient height to be at least coextensive with the spring clip contacts; said shroud body member having a partially open bottom with an integral bridging portion extending transversely between said side walls, said bridging portion and said side and end walls defining a pair of openings through which said clip contacts are adapted to extend; said bridging portion including a fuse engaging surface, a mounting pedestal integral with said bridging portion and extending in a direction opposite from the direction of the extension of said side walls and adapted to be inserted through a suitable opening in the support base, and mounting means for loosely securing said pedestal in said opening, said pedestal being of a suitable length to provide a loosely captive mounting of said ejector/shroud member with respect to said support base, whereby to permit a cartridge fuse to be inserted between said clip contacts when said ejector/shroud member is fully seated on said support base and whereby said fuse engaging portion of said bridging portion is operative to eject said mounted fuse from between said clip contacts when said shroud is lifted slightly from said support base.

2. A fuse ejector/shroud member as set forth in claim 1 wherein said shroud member is formed of a molded semi-resilient plastic material.

3. A fuse ejector/shroud member as set forth in claim 2 wherein said fuse engaging surface of said bridging portion includes a fuse ejecting abutment adjacent one of said openings through which said clip contacts extend whereby one end of said fuse is ejected from the associated clip contact by the lifting of said shroud/ejector from said support base on its loosely captive pedestal.

4. A fuse ejector/shroud member as set forth in claim 3 wherein said abutment includes a concave surface for engagement with said fuse.

5. A fuse ejector/shroud member as set forth in claim 2 and characterized by the inclusion of guide tongues formed on the inner surface of each of said end walls to guide the ends of said fuse into longitudinal position relative to said clip contacts.

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