US3868618A

US3868618A - Fuse holder having indicator means

Info

Publication number: US3868618A
Application number: US434730A
Authority: US
Inventors: Frank Peter Dola
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1974-01-18
Filing date: 1974-01-18
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25

Abstract

Fuse holder for utility power line comprises a cylindrical housing having a closed end through which the fuse extends. One conductor is connected to the fuse at this closed end. An indicator sleeve is slidably mounted in the housing for sliding movement between a retracted position, in which it is within the housing, and an extended position, in which it projects substantially beyond the housing. A spring normally biases the sleeve to the extended position. In use, the spring is compressed and the sleeve moved to its retracted position. A second conductor is secured to the sleeve and to the fuse so that if the fuse is blown, the spring moves the sleeve to its extended position.

Description

United States Patent 1191 Dola 11] 3,868,618 [451 Feb. 25, 1975 FUSE HOLDER HAVING INDICATOR MEANS 52 u.s.c1 337/206, 337/241,337/244 51 1111.01; ..H0lh 85/30 [58] Field ofSearch 337/173,17s, 194, 206,

[5 6] References Cited UNITED STATES PATENTS 5/1943 Triplett 33.7/24l X 2/1967 Lindell 337/241 X Primary Examiner-JD. Miller [57] ABSTRACT Fuse holder for utility power line comprises a cylindrical housing having a closed end through which the fuse extends. One conductor is connected to the fuse at this closed end. An indicator sleeve is slidably mounted in the housing for sliding movement between a retracted position, in which it is within the housing, and an extended position, in which it projects substantially beyond the housing. A spring normally biases the sleeve to the extended position. In use, the spring is compressed and the sleeve moved to its retracted position. A second conductor is secured to the sleeve and to the fuse so that if the fuse is blown, the spring moves the sleeve to its extended position.

6 Claims, 7 Drawing Figures 1 FUSE HOLDER HAVING INDICATOR MEANS BACKGROUND OF THE INVENTION This invention relates to fuse holders for fuses of the type used in utility power lines to fuse a transformer or for other purposes. Fuse holders of this type must be sturdy and durable since they are continuously exposed to the elements and must function effectively for long periods of time. Fuse holders of this type are usually designed to provide a visual indication if the fuse has blown so that the utility worker can determine whether or not a particular fuse has been blown without climbing the utility pole near which the fuse is installed.

Most of the fuse holders which are presently used are satisfactory from a functional standpoint but they are relatively heavy and complicated and require heavy duty mounting hardware for their installation. They are also relatively high-priced because of their complexity and the installation is a time consuming operation.

The instant invention is specifically addressed to the problem of providing a relatively simple and light weight fuse holder which can be readily installed on a utility line and which is capable of withstanding continued exposure to a variety of adverse weather conditrons.

It is accordingly an object of the invention to provide an improved fuse holder for fuses of the type used on power utility lines. A further object is to provide a light weight fuse holder which can be constructed, for the most part, of durable plastic materials. A further object is to provide a light weight fuse holder which can be installed without the requirement of relatively heavy duty mounting brackets or the like. A further object is to provide a fuse holder having improved indicator means for indicating whether or not the fuse has blown.

These and other objects of the invention are achieved in a disclosed embodiment thereof which is briefly described in the foregoing abstract, which is described in detail below, and which is shown in the accompanying drawing in which:

FIG. 1 is a side view, partially in section, of a fuse holder in accordance with the invention having an unblown fuse installed therein.

FIG. 2 is a sideview of a fuse of a type which is adapted to be installed in the fuse holder of FIG. 1.

FIG. 3 is a fragmentary sectional view of the lower portion of the fuse holder of FIG. 1 showing the positions of the parts after the fuse has blown.

FIG. 4 is a view taken along the lines 4--4 of FIG. 1.

FIG. 5 is a schematic view showing the manner of installing a fuse for a transformer using a fuse holder in accordance with the invention, this view showing the appearance of the fuse holder when the fuse is unblown.

FIG. 6 is a view similar to FIG. 5 but showing the appearance of the fuse holder after the fuse has been blown.

FIG. 7 is a schematic view showing the manner in which a fuse holder in accordance with the invention can be used to fuse a temporary feeder line extending from a main power line.

The disclosed embodiment of the invention is adapted to receive a fuse of the type shown at 2 (FIG. 2) comprising a generally cylindrical body 4 having a nut 6 on its upper end which has a radially extending collar 7. The contact surface for one external conductor is provided at the upper end ofthe fuse and is shown at 8. The body 4 contains the fusable metal and a flexible conductor 10 is crimped onto, and extends from, the fusable material and from the lower end of the fuse. The fusable element and the conductor 10 are able to withstand a substantial tensile force but if the fuse is blown, the conductor 10 can be pulled, or will fall, downwardly.

A preferred form of fuse holder 12 in accordance with the invention comprises a cylindrical housing generally indicated at 14 having a cap member 16 assembled to, and mounted on, its upper end to close the upper end. A relatively thin walled cylindrical body 18 extends from the cap member and is secured to the cap by means of an annular flange 20 to which the body is bonded or otherwise secured. Cap member 16 has a central cylindrical boss 22 which has a flat upper surface 26 and an axial opening 24 which communicates with the interior of the housing.

The fuse 2 is installed in the housing by passing the body portion 4 thereof through the opening 24 until the collar 7 is against the surface 26. A cap nut 28 is then assembled to the cap member 16 by means of complementary threads 30 provided on the extension 22 and the interior of the cap nut. The cap nut is of plastic, as are the cap member 16 and the body 18, however, a rigid conductor rod 30 is axially mounted in the cap nut 28 so that when the cap nut is threaded tightly onto the cap member, the lower end of the rod 30 will be electrically connected to contact surface 8 of the fuse. Rod 30 extends upwardly from the cap nut and is connected by means ofa conventional clamp 32 to the stirrup portion 34 of a hot wire clamp 36 (see FIG. 5).

A relatively thin walled indicator sleeve 40 is slidably contained in the lower portion of the cylindrical portion 18 and is movable between a retracted position, in which it is substantially fully retracted in body 18, to an extended position as shown in FIG. 3. When the indicator sleeve is in its extended position, a substantial portion of its lower end 46 projects below and beyond the lower end of the body 18. Indicator sleeve 40 is guided during movement between its two extreme positions, and the limits of these positions are defined, by pins 44 which are mounted in the body 18 and which extend through axial slots 42 in the indicator sleeve.

The lower portion 38 of the indicator sleeve is arcuate as shown and has a connecting device 48 mounted on its lower end. This connecting device comprises a cylindrical member having a reduced diameter section 50 on its lefthand end which is provided with an opening through which the conductor 10 extends. The end of the conductor 10 is clamped against the shoulder 49 by means ofa nut 52 which is threaded on this reduced diameter portion. The adjacent larger diameter portion 54 ofthe connecting device extends slidably through an opening in the indicator sleeve and through an opening in an arcuate bracket 56. The bracket has integral mounting feet 58 which are secured to the external surface of the lower portion 46 of the sleeve by fasteners 60. A nut 62 is threaded onto the end of the larger diameter portion 54 of the connecting device and a washer 64 is interposed between this nut and the bracket 56. The external conductor is connected to connecting device 48 by being inserted through a transverse opening in the larger diameter portion 54 which is normally between the surface of the lower end of the sleeve and the internal surface of the bracket. The nut 62 is then tightened to draw the connecting device rightwardly as viewed in the drawing until the conductor 55 is firmly pressed against the opening in the connecting device.

A compressable spring 66 is interposed between the upper end of the indicator sleeve and the downwardly facing shoulder 68 of the flange 20 of cap member 16. This spring normally biases the indicator sleeve to its extended position as shown in FIG. 3 but the spring can be compressed as shown in FIG. 1 when the sleeve is moved to its retracted position.

In use, the fuse is installed by passing it through the opening 24,as explained above, and threading the cap nut 28 onto the cap member 22. Thereafter, the sleeve is moved upwardly and into the cylindrical body 18 and the spring 66 is compressed. The lower end of the flexibleconductor is then clamped to the connecting device48 and the fuse holder is then installed between the stirrup 34vand the external conductor 55. When the fuse is blown, the indicator sleeve is biased to its extended position to'provide a visual indication of the condition of the fuse.

Fuse holders in accordance with the invention are adapted to be-used to fuse a transformer 72 mounted on a utility pole. 74 andconnected to a main power line 70. As shown inFIG. 5, the fuse holder and fuse can be installed with only a conventional hot wire clamp 36 and the auxiliary clamp 32 which connects the stirrup to the conductor 30in the cap nut 28. As illustrated by FIG. v6, the extended indicator sleeve gives an immediate indication that the fuse has been blown.

The easily installed and the light weight hardware shown in FIGS. 5 and 6 can be used with a fuse holder in accordance with the invention for the reason the fuse holder itself is not heavy and bulky. Most of the parts of the fuse holder can be produced of a durable weather resistent and strong plastic such as a polycarbonate and the only metal parts required in a'fuse holder-in accordancewith the invention are the conductor 30, the connecting device 48, and the spring member 56 although .the indicator sleevev can be of metal if desired.-

- to the ends of the feeder lines and are connected to the main lines 76 adjacent to the utility pole. Again, relatively simple connecting clamps (not specifically shown in FIG. 7) can be used to connect the conductors ex-- tending from the fuse to the

lines

76, 78.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

What is claimed'is:

1. A fuse holder adapted for use with a current limiting fuse, said fuse being cylindrical and having a radially extending collar at one end thereof, a conductive contact area centrally located with respect to said collar, and a flexible conductor extending from the other end thereof, said fuse holder comprising:

a generally cylindrical housing having a closed end and an open end, said closed end having a flat ex-' ternal surface and an axially extending opening extending therethrough and communicating with the interior of said housing,

a cap member removably mounted on said closed end, said cap member having a cap member conductor extending axially therethrough,

an indicator sleeve concentrically and slidably mounted on said housing, said indicator sleeve having a first end which is proximate to said closed end of said housing and having a second end which is remote from said closed'end, said sleeve being movable between a retracted position, in which said second end thereof is adjacent to said open end of said housing, and an extended position, in which said second end is remote from said open end and portions of said sleeve extend substantially beyond said housing,

means for securing said flexible conductor to said sleeve and for securing an external conductor to said sleeve, and compressible resilient means interposed between said first end of said sleeve and said closed end of said housing whereby,

upon inserting said fuse through said opening and locating said collar on said surface, assembling said cap member to said housing, moving said sleeve to saidretracted position, and securing saidflexible conductor to said sleeve, said sleeve will be retained in'said retracted position by said fuse, and if said fuse should fail, said sleeve will be movedto said extended position under the influence of said resilient means thereby to provide a visual indication of the failure of said fuse.

2. A fuse holder as set forth in claim 1, said indicator sleeve being inside of said housing.

3. A fuse holder as set forth in claim 2, said closed end having a cap thereon, said opening extending through said cap. a

4. A fuse holder as set forth in claim 2, said closed end having an axially extending cylindrical boss and having a cap member threaded onto said boss, said opening extending through said cap 'member and through said boss, said collar. on said fuse being adapted to be clamped between'said cap and said boss.

5. A fuse holder as set forth in claim 4, said cornpressible resilient means comprising a coil spring.

6. A fuse holder in combination with a current'limiting fuse, said fuse comprisinga cylindrical member having a radially extending collar adjacent to one end thereof and a first conductor extending-from the other end of said fuse, said fuse having a contact surface centrally located with reference to said collar at said one end, said fuse holder comprising:

a generally cylindrical fuse holder housing having a closed end and an open end, said closed end having a flat external surface extending normally of the axis of said housing and having a central opening, said fuse being disposed'in said housing with said collar on said flat surface and with said fuse body means for limiting axial movement of said first end of said indicator body past said open end ofsaid housmg, said indicator body being normally retained in said housing by said fuse and said first conductor against the biasing force of said resilient means whereby, upon failure of said fuse, said indicator body is moved to an extended position under the influence of said resilient means thereby to indicate failure of said fuse.

Claims

1. A fuse holder adapted for use with a current limiting fuse, said fuse being cylindrical and having a radially extending collar at one end thereof, a conductive contact area centrally located with respect to said collar, and a flexible conductor extending from the other end thereof, said fuse holder comprising: a generally cylindrical housing having a closed end and an open end, said closed end having a flat external surface and an axially extending opening extending therethrough and communicating with the interior of said housing, a cap member removably mounted on said closed end, said cap member having a cap member conductor extending axially therethrough, an indicator sleeve concentrically and slidably mounted on said housing, said indicator sleeve having a first end which is proximate to said closed end of said housing and having a second end which is remote from said closed end, said sleeve being movable between a retracted position, in which said second end thereof is adjacent to said open end of said housing, and an extended position, in which said second end is remote from said open end and portions of said sleeve extend substantially beyond said housing, means for securing said flexible conductor to said sleeve and for securing an external conductor to said sleeve, and compressible resilient means interposed between said first end of said sleeve and said closed end of said housing whereby, upon inserting said fuse through said opening and locating said collar on said surface, assembling said cap member to said housing, moving said sleeve to said retracted position, and securing said flexible conductor to said sleeve, said sleeve will be retained in said retracted position by said fuse, and if said fuse should fail, said sleeve will be moved to said extended position under the influence of said resilient means thereby to provide a visual indication of the failure of said fuse.

3. A fuse holder as set forth in claim 2, said closed end having a cap thereon, said opening extending through said cap.

4. A fuse holder as set forth in claim 2, said closed end having an axially extending cylindrical boss and having a cap member threaded onto said boss, said opening extending through said cap member and through said boss, said collar on said fuse being adapted to be clamped between said cap and said boss.

5. A fuse holder as set forth in claim 4, said compressible resilient means comprising a coil spring.

6. A fuse holder in combination with a current limiting fuse, said fuse comprising a cylindrical member having a radially extending collar adjacent to one end thereof and a first conductor extending from the other end of said fuse, said fuse having a contact surface centrally located with reference to said collar at said one end, said fuse holder comprising: a generally cylindrical fuse holder housing having a closed end and an open end, said closed end having a flat external surface extending normally of the axis of said housing and having a central opening, said fuse being disposed in said housing with said collar on said flat surface and with said fuse body extending through said opening and coaxially into said housing, said housing having external threads on said one end, a fuse holder cap of insulating material threaded onto said closed end, said cap having a second conductor extending axially therethrough, said conductor being in electrical contact with said contact surface, an indicator sleeve slidably and concentrically mounted in said housing, said sleeve having a first end which is proximate to, but spaced from, said closed end of said housing and having a second end which is remote from said closed end, said first conductor being secured to said indicator sleeve adjacent to said second end, means for connecting on external conductor to said first conductor, compressed resilient means interposed between said first end of said indicator sleeve and said closed end of said housing, said resilient means biasing said indicator body towards said open end of said housing, and means for limiting axial movement of said first end of said indicator body past said open end of said housing, said indicator body being normally retained in said housing by said fuse and said first conductor against the biasing force of said resilient means whereby, upon failure of said fuse, said indicator body is moved to an extended position under the influence of said resilient means thereby to indicate failure of said fuse.