US3588775A - Fuse holder for electrical circuits - Google Patents

Abstract

A FUSE CLIP ADAPTER OF AN L-SHAPED CONFIGURATION FOR LIMITING THE POSITION OF A FERRULE CONTACT OF A STANDARD ENCLOSED CARTRIDGE TYPE FUSE RETAINED IN A U-SHAPED FUSE CLIP. THE ADAPTER INCLUDES MEANS FOR RETAINING ITS BASE SECTION WITHIN THE BOTTOM FLAT POSITION OF THE FUSE CLIP WHEREBY THE UPSTANDING STOP SECTION EXTENDS WITHIN THE OPEN FREE ENDS OF THE FUSE CLIP FOR CONTACT WITH THE FERRULE OF THE FUSE.

Description

United States Patent [72] Inventor Edmund F. Poehlrnan, Jr.

Silver Spring, Md. [21] Appl. No. 783,159 [22] Filed Nov. 1, 1968 Division of Ser. No. 646.534.,lune 16, 1967. Pat. No l-134.789 [45] Patented June 28, 1971 [73] Assignee Fuse Indicator Corporation Rockville, Md.

[54] FUSE HOLDER FOR ELECTRICAL CIRCUITS 3 Claims, 16 Drawing Figs.

337/226 ....H0lh 85/24 337/208, 209, 213, 214, 215, 225, 226; 317/119 (Cursory) Primary Examiner-Bernard A. Gilheany Assistant Examiner-Dewitt M. Morgan Attorney Linton & Linton ABSTRACT: A fuse clip adapter of an L-shaped configuration for limiting the position of a ferrule contact of a standard enclosed cartridge type fuse retained in a U-shaped fuse clip. The adapter includes means for retaining its base section within the bottom flat position of the fuse clip whereby the upstanding stop section extends within the open free ends of the fuse clip for contact with the ferrule of the fuse.

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FUSE HOLDER FOR ELECTRICAL CIRCUITS This is a division of application Ser. No. 646,534 filed June 16, l967 and now US. Pat. No. 3,434,789.

CROSS REFERENCE US. Pat. No. 3,052,781 issued Sept. 4, I962 discloses a single and double fuseholder employing standard cartridge type fuses retained therein by fuse clips separated at predetermined fixed distances from one another and carried by the cover of the fuseholder. The present protectors for electrical circuits are an improvement thereover.

BACKGROUND OF THE INVENTION Manufacturers of standard cartridge type fuses produce a line of fuses having a cartridge or casing of the same outside diameter but in varying lengths according to their ampere rating. For instance there is presently on the market a Midget cartridge fuse type SAB having a casing of thirteen thirtyseconds inch in diameter and Wainches in length with a rating of -30 amperes. Also there is on the market standard Type SC cartridge fuses each having a diameter of thirteen thirtyseconds inch but with varying lengths of, for example, 1 5/16 inches in length for 0-15 amperes; 1 13/32 inches in length for 16-20 amperes; l'kinches in length for 21-30 amperes; and 2%inches in length for 31-60 amperes. Manufacturers of fuse blocks, panel boards and holders for fuses have to space fuse clips apart thereon at predetermined distances so as to accommodate the different lengths of the foregoing Type SC and Midget fuses. For example, one set of clips should be spaced apart so as to accommodate the fuses having 0-15 ampere rating; a second set of clips should be spaced apart so as to accommodate the 16-20 ampere rating fuses; the third set of clips should be spaced apart so as to accommodate the 21-30 ampere rating fuses and the fourth set of clips. should be spaced apart so as to accommodate the 31-60 ampere rating fuses. Owing to the length of 2%inches for the 31-60 ampere rating fuses none of the foregoing lower ampere rating fuses would fit within the clips spaced for the 31-60 ampere rating fuses. However, it is possible to interchange or replace fuses of the lower ampere ratings in any one of their sets of fuse clips and to prevent against over load currents that might'occur incidental 'to the use of the improper fuse, by providing an adapter or stop for one or more of the fuse clips whereby only a fuse of the required proper ampere rating can be applied to each set of fuse clips. These adapters can be made from electrical insulating materials such as phenolic or electrical conducting materials, such as brass and also can be fixedly applied to a fuse clips with a suitable epoxy adhesive. I also provide an indicating or nonindicating holder for one or a plurality of fuses including fuse clips to which said adapters or stops can be applied.

The fuse holders of the aforementioned U.S. Pat. No. 3,052,781 requires nuts and bolts for fastening the same to a panel board for example which is not required in the present fuseholders. The patented structure also does not include the present structure for preventing the accidental reversal of the cap of the fuseholder on the body thereof and also does not include the simplified structure of the present fuseholder whereby a pair of clips are employed for retaining the fuseholder on a panel board, the cap on the fuseholder body and an insulating partition within the fuseholder body for separating the fuses when positioned therein.

The present fuseholders have a high level of safety from possible electrical shock to personnel changing fuses therein as with the cap removed current carrying parts of the present fuseholder are insulated, removed or encased to prevent accidental contact with the same. The present fuseholder with the fuse clips in one position will accept fuses having a wide range of lengths of, for example. from l%inches to 1%inches in length and thirteen thirty-seconds inch in diameter. The fuse length to be accommodated by any set of fuse clips may be limited by inserting an adapter into one or both fuse clips. If longer fuses are to be used the fuse clips will have to be positioned accordingly.

On the present double fuse holder the clip and body are keyed to prevent reverse installation of the cap on the body so that if the cap should carry fuses of different ampere ratings they can only be inserted in the body in their proper location.

The caps of the present indicating and nonindicating fuseholders are of the same size and configuration permitting the same to be readily interchanged on the same body as well as reducing the cost which would be incurred by different caps for these purposes. The caps are friction fitted to the body and therefore can be removed and installed without the need for twisting or loosening or removal of fasteners therefore.

The present fuseholders can be mounted upon a panel board, for example, by means of snap clips that are an integral part of the fuseholder and the fuseholder is snapped into place in a rectangular mounting hole in the panel board without the need of tools or removing or installing mounting hardware. The snap-in clips will fit panel boards having a thickness range of one-sixteenth inch to three thirty-seconds inch.

The present fuseholder can be singularly arranged on the panel board or arranged in a series in a common mounting cut out of the panel board in any desired quantity or combination. This eliminates the necessity for providing a separate panel cut out for each fuseholders where a plurality of fuseholders are to be mounted side by side.

On the present single fuseholder the contact clips of the body thereof and the long leg of the fuse clips of the cap are alternated to provide even side tension on the cap. This assists in the mounting of the cap on the body and also prevents the caps from being raised up on one side when mounted.

In the accompanying drawings:

FIG. I is a top view of a single fuseholder according to the present invention.

FIG. 2 is a side elevation partly in section of said fuseholder.

FIG. 3 is an end view partly in section of the fuseholder.

FIG. 4 is a bottom view of the cap forming part of the fuseholder.

FIG. 5 is a cross-sectional view of said cap.

FIG. 6 is a perspective view of an insulating member forming part of the fuseholder.

FIG. 7 is a top view, reduced size, of the fuseholder body.

FIG. 8 is an exploded perspective side view of a single fuseholder prior to the mounting of the cap of the body thereof.

FIG. 9 is a side elevation partly in section of the body of a double fuseholder.

FIG. I0 is a top view of said double fuseholder with the insulating panel partly broken away.

FIG. 11 is a bottom view of the cap of the double fuseholder.

FIG. I2 is an end view partly in section of the double fuseholder.

FIG. 13 is an exploded perspective view of the double fuseholder prior to the mounting of the cap on the body.

FIG. 14 is an enlarged perspective view of the adapter for fuse clips.

FIG. 15 is an enlarged sectional view taken on line 15-15 of FIG. 8, and;

FIG. 16 is a cross-sectional view taken on line 15-15 of FIG. 15.

Referring now more particularly to the accompanying drawings wherein like and corresponding parts are designated by similar reference characters numeral I generally indicates the cap of the single fuseholder shown in FIGS. 1-8 inclusive. Said cap is of an electrical insulating material such as a phenolic compound melamine, urea formaldehyde or the like and has a flat top 2 with projections 3 and 4 extending'from the ends thereof and an interior rectangular wall 5 from'which extends shoulder 6 to a recess 7 while a second recess 8 extends deeper into said cap than recess 7 in the central portion of said cap. Recesses 9 are provided in wall 5 in each of said projections 3 and 4. A pair of fuse clips each generally designated by the reference numeral I0 are retained each in an opposite end of recess 7 by drive pins 11 each extending through the flat bottom 12 of the fuse clips into cap 1. Each fuse clip besides flat bottom 12 has an outwardly curved portion 13, inwardly curved portion 14, outwardly curved portion 15 and outwardly extending lip 16 providing one leg of said clip integral with said base. The clip further has an outwardly curved portion 17. inwardly curved portion 18, outwardly curved portion 19, inwardly curved portion 20, and a straight end portion 21 provided a second leg of said clip integral with said base and which end portion 21 extends beyond the lip 16 of the first leg while the portions 15 and 19 of the legs are curved for detachably receiving ferrule B or C of a cartridge fuse A. Such fuse clips are made of a resilient electrically conducting material such as brass, copper, beryllium copper or the like.

In the indicating form of the fuseholder. the cap thereof as shown in FIGS. 4 and have a neon or incandescent lamp 22 with one electrode lead 23 of the lamp being fixedly connected to or under the head of a drive pin 11 while a second electrode lead 24 of the lamp is twistedly connected to wire 25 of a resistor 26 while the other lead 27 of said resistor is fixedly connected to the other of said drive pins 11. Said leads can be attached to said drive pins by solder or under the head of the drive pin. Lamp 22 and resistor 26 are positioned within recess 8 of said cap. The nonindicating cap 2 as shown in FIGS. 2 and 3 do not include such lamp and resistor.

The body of the single fuseholder generally indicated as 28 is also of an electrical insulating material and has a medial lateral flange 29 extending around the outside thereof, a flat bottom 30 and a partition 31 extending laterally across and from said bottom 30.

Said body further has a pair of end walls 32, a pair of sidewalls 32a, an interior rectangular shoulder 33 extending inwardly from said walls to an elongated recess 34 in the bottom of said body. A pair of square openings 35 extend through said body bottom each into an opposite end of said recess 34. A pair of bolts 36 each have a square shank 37 mating with one of said square openings 35 and extend through said body bottom. A pair of washers 38 each have one of said bolts extending therethrough and are positioned between said body bottom 30 and a pair of nuts 39 in threaded engagement with each of said bolts.

An insulator body has a pair of right-angle walls 40 extend ing normal to a bottom 41 with each right-angle wall positioned against an end wall 32 and a portion of one sidewall 32a. Bottom 41 also has a pair of slots 43 with each slot alongside one of the sidewall 40a of one of said right-angle walls.

A pair of contact springs 42 each have a base with a square opening through which extends the square shank 37 of a bolt 36 and an upright curved leg 44 beneath one of said slots 43.

Each end wall 32 has a slot 45 extending from the bottom to the top thereof and in flange 29 while bottom 30 has an in dentation 46 at each end thereof in line with one of said slots 45. The top of each end wall 32 has a recess 47 in line with the slot 45 of said end wall.

A pair of spring mounting clips each have a center leg 45a positioned in one of said slots 45, a hook end 46a in the indentation 46 therebelow, a second hook 47a in slot 47 and a curved tongue 48 in said second end. Further, said spring mounting clips each have a pair of substantially V-shaped arms 49 extending alongside leg 45a on each side of the same and spaced from the corresponding end wall 32. Each arm 49 has lateral medial crease 50. Said spring mounting clips are preferably formed of a spring steel material.

In the use of the single fuseholder a cartridge fuse A has the ferrules B and C thereof detachably mounted in the clips as shown in FIG. 8. Thcreupon cap 1 is mounted on the open top of body 28 by inserting legs 21 of said clips each through one of the insulator openings 43 until it engages the leg 44 of one of the spring contact. At such time shoulder 6 engages the top edge of walls 32 and 32a of said body and tongues 48 press into the recesses 9 of wall 5. To remove the cap 1 from said body therefore it is only necessary to pull the cap from the body due to the snap fit.

To mount the fuseholder upon a panel board D it is only necessary to push said body through a corresponding opening in said panel until flange 29 engages said panel. During this mounting operation arms 49 are compressed against end walls 32 until such time as they clear panel D whereupon they will spring back to the position shown in FIG. 2 retaining the fuseholder body on the panel.

Wires (not shown) are then connected to bolts 36 and current therefrom can pass through said bolts to spring clip 42, clips 10 and fuse A.

When cap 1 contains lamp 22 and should the fusible element in the fuse be ruptured due to a current over load the current would pass from one clip 10 through lead 27, resistor 26, leads 25 and 24, lamp 22 and lead 23 to the other clip 10 causing said lamp 22 to light and shine through the relatively thin translucent or transparent bottom of cap 1 to indicate the blown condition of the fuse.

Lamp 22 and resistor 26 can be cemented in place in said cap with the lamp and resistor as well as the leads embedded in the adhesive. The leads 23 and 27 can be soldered to the fuse clips 10.

The present double fuseholder which is shown in FIGS. 9- -13 inclusive has a cap generally indicated at 51 which is of an electrical insulating material and has a rectangular interior wall 52 from which extends a shoulder 53 to a second rectangular wall 54 with a pair of spaced apart shoulders 55 providing a central recess 56. A partition57 extends from shoulder 53 across recess 56 and shoulders 55 providing two companments within said cap. Partition 57 further has a tongue 58 extending from the edge of said partition and positioned to one side of the center of said partition. Two pairs of clips 10 are attached to said cap with each clip being mounted on one of the shoulders 55 by means of a drive pin 11 extending through the base of the clip into the shoulder 55.

For the indicating fuseholder, the cap 51 as shown in F 10. 11 also contains a pair of neon or incandescent lamps 22 and a pair of resistors 26. Each lamp 22 has a lead 24 connected to lead 25 of one resistor and a second lead 23 connected to a drive pin 11 and resistor lead 27 connected to the other drive pin 11 with each connected lamp and resistor being in recess 56 on a different side of partition 57. Said lamps and resistors can be embedded in cement within recess 56 while cap 51, as can cap 1, can be of a transparent or translucent plastic. The cap 51 for the nonindicating fuseholder does not contain a lamp and resistor.

The body 59 of the double fuseholder is also of an electrical insulating material and has a lateral flange 60 extending around the exterior thereof as well as a cross-shaped partition 61 extending from the bottom 62 of said body. Said body further has an interior rectangular wall 63 extending to a shoulder 64 providing an open top recess in said body. A pair of recesses 65 are each positioned between shoulder 64 and a center partition 65a. A pair of square openings 66 extend through the bottom of each of said recesses 65 and bottom 62 of said body. A contact spring 42 is positioned above each of said openings 66 with a bolt 36 extending through the bottom of the contact spring, and opening 66 and retained by nuts 39.

An insulator body 67 of electrical insulating material is mounted upon shoulder 64 and partition 65a and has an upright partition between the opposite ends of wall 63 dividing the open top recess of said body into two compartments corresponding to the compartments on opposite sides of partition 65a and also partition 57 of said cap 51. Said insulator body 67 further has two pairs of openings 68 with each pair thereof adjacent to but on opposite sides of partition 70. Said partition 70 also has curved faces 69 on both sides thereof with each face curving downwardly towards one of said openings 68. Partition 70 further has a top edge recess 71 shaped and positioned for receiving tongue 58 of cap 51 only when said cap is mounted on said body in a given position. Bottom 62 has a pair of indentations 72 each in an opposite end thereof while said body has a recess 45b in each of its opposite ends for receiving one of the spring mounting clips 45a.

That is, hook end 46:: of each spring mounting clip 45a is mounted in one of said bottom recesses 72 and the opposite end 47a extends over wall 63 engaging the top of partition 70 so that the two spring mounting clips 45a retain the insulator body 67 in the fuseholder body. Each spring mounting clip 45a has a pair of resilient legs 49 extending normal to bottom 62 and between said bottom and flange 60 and also a spring tongue 48 adjacent hoolt end 47a. Flange 60 also has a pair of recesses 73 each in line with one of said recesses 45!) and in each of which one of said spring mounting clips extends.

in the use of the double fiiseholder two cartridge fuses A are each mounted in the pair of clips in each of the compartments of said cap 51. Thereupon, the cap 5] is mounted upon the top of body 59 with tongues 48 pressing against the end portions of the cap wall 52 retaining the cap on said body until lifted therefrom. When placing the cap on the body, legs 21 of said clips 10 are each guided by a face 69 of partition 70 into and through one of the openings 68 until the leg 21 is in contact with leg 44 of the spring contact 42. Thereupon bolts 36 can be connected to an electrical circuit (not shown) so that current can pass through each pair of bolts 36, spring contact 42, clips 10 and the fuse A. lf required, the fuses A mounted in cap 51 can have different ampere ratings or have the same ampere ratings depending upon the circuit to which they are connected.

When an indicating cap 51 such as shown in FIG. 11 is employed and either of the fuses A therein should become ruptured or blown due to an overload of a current passing thereto, the current would pass from the clips 10 bypassing the ruptured fuse to the resistor 26 and lamp 22 connected to said clips causing the lamp 22 to light and the light would show through the relatively thin transparent or translucent top of the cap 51. However, it is to be appreciated that a cap 51 without the resistors and lamps mounted therein can equally as well be used.

When cap 5! is lifted from body 59, the terminals consisting of bolts 36 and spring contacts 42 are covered by partition 67 so that a user thereof can not receive an electrical shock when removing or replacing fuses or the cap on said body.

Also the double fuseholder can be mounted on a panel board by merely pushing said body through a correspondingly shaped opening in the panel board until flange 60 abuts one face of the panel board whereupon the spring legs 49 would snap against the opposite face of the panel board retaining the fuseholder thereon.

A plurality of single fuseholders or plurality of double fuseholders or a combination thereof can be mounted side-byside upon a panel board for example by providing an opening in said panel board of a configuration for this purpose.

Should the fuses A mounted in the cap 51 have different ampere ratings they can only be mounted upon the body 59in their proper position due to the fitting of tongue 58 into recess 71.

A fuse clip adapter is shown in FIGS. 14-16 inclusive which adapter 74 is of an L-shaped configuration having a leg '75 with straight sides 76 and 79 and a base leg 78 having slanting shoulders 77 and 80 slanting inwardly towards sides 76 and 79 respectively of leg 75. Said bottom 78 further has a slot 83 in the bottom face 81 thereof with a detent 82 extending across said slot adjacent leg 75.

As referred to hereinbefore standard cartridge fuses A of different ampere ratings are produced with the same casing diameter but with difierent overall lengths. Thus when standard fuse clips are mounted upon a base they nonnally have to be spaced apart a distance to accommodate the length of the fuse to be mounted thereon. However, if the fuse clips are mounted apart a distance toaccommodate a cartridge fuse of, for example, 21-30 ampere ratings and having a length of Hsinches it is possible to attach one of the cartridge fuses of the shorter lengths and lower ampere ratings thereto.

Adapter 74 can be mounted upon a standard fuse clip as shown, by way of an example, in FIGS. 15 and 16 by sliding slot 83 over the head of the drive pin ll holding the fuse clip to the base until detent 82 slides over said drive pin head and leg 75 abuts shoulder 6 and detent 82 abuts said drive pin head. Shoulders 77 and 80 of the adapter would thus slide between the curved portions 13 and 17 of the fuse clip and leg 74 would extend between the legs of the fuse clip. Thus, with a pair of fuse clips mounted for a 21-30 ampere rating fuse, for example, the addition of one adapter to one of the fuse clips would prevent the 2l-30 ampere rating fuse to be mounted thereon, but would permit the accommodation of a lower ampere fuse. Still further, a pair of said adapters 74 could each be mounted on a different one of the fuse clips so that only a fuse having an 0- l5 ampere rating, for example, could be mounted on the fuse clips and not a fuse of higher ampere ratmg.

In view thereof, a manufacturer can install fuse clips each pair of which all having the same spacing and yet accommodate the proper fuse only by the addition of one or two adapters or said adapter could be removed to accommodate any change in the electrical circuit ampere rating connected thereto. Thus a fuse of an ampere rating greater than required by the electrical circuit connected to the fuse clips could not inadvertently be attached to the fuse clips.

For purpose of an example only, an adapter 74 is shown in the drawings attached to one of the fuse clips 10 of the present fuseholders but it is to be appreciated that more than one adapter can be employed on more than one fuse clip and also the adapters can be mounted on fuse clips attached to other bases than the present caps.

The present invention is capable of considerable modifications and such changes thereto as come within the scope of the appended claims is deemed to be a part thereof.

lclaim:

1. An adapter for limiting the position of a ferrule contact of a standard enclosed cartridge type fuse retained in a U-shaped fuse clip having a flat bottom portion secured to a support of an electrical insulating material comprising in combination a single unit consisting of a base section and a right-angular stop section insertable within the U-shaped fuse clip, means for retaining said base section with the bottom fiat portion of said fuse clip, and said stop section extending within the open free ends of said U-shaped fuse clip for contact with the ferrule of the fuse.

2. An adapter as claimed in claim 1 wherein said means for securing said U-shaped fuse clip to the support comprises a drive screw with its head projecting above the flat bottom portion of the fuse clip, the bottom face of said base section having a slot formed therein for receiving the head of said drive screw and a detent formed with said base section projecting within said slot for locking engagement with the head of said drive screw.

3. An adapter as claimed in claim 2 wherein said unit is of an L-shaped configuration with the base section having oppositely slanting surfaces extending from said bottom face to opposite sidewalls of said unit for contact with the legs of the U-shaped fuse clip for retaining said detent in contact with the head of said drive screw.

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