US1935453A

US1935453A - Electric fuse

Info

Publication number: US1935453A
Application number: US373725A
Authority: US
Inventors: Mar Frank C La
Original assignee: GREAT WESTERN FUSE Co
Current assignee: GREAT WESTERN FUSE Co
Priority date: 1929-06-26
Filing date: 1929-06-26
Publication date: 1933-11-14
Anticipated expiration: 1950-11-14

Description

Nov. 14, 1933. lr:q C, LA MAR 1,935,453

ELECTRIC FUSE Filed June 26. 1929 2 Z9 some Patented Nov. 14, 1933 PATENT OFFIC.

Urrso STATES Fuse Company, New York,

N. Y., a'corporation of Delaware Appiicatien June 26, 1929. Serial No. 373,725

11 Ciainis.

This invention relates to electric fuses, particularly to that type of fuse known as an enclosed fuse andmore especially to such fuses of the knife blade type.

A principal object of this invention is the production of a fuse of the type specified which consists of a minimum of parts necessarily detached for renewing the fusible element of such A further object is the production of a fuse of the type Yspecified in which at a maximum of places a material is presented to the voiatiiized fuse metal which is of such a nature that the volatilized fuse metal will practically not adhere thereto.

A further object of the invention is the production of a fuse of the type specified in which the knife blades will be spaced a constant distance apart by an insulating body so formed and positioned that it presents a minimum of surfaces and obstruction to the free iiow of the vclatiiiaed metals and gases generated. Y

A further object of the invention is the production of a fuse of the type specified which will provide a free but tortuous passage for the escape of volatilized fuse metal and gases.

Further objects and advantages will appear as the description of the particular physical embodiment selected to illustrate the invention progresses and the novel features will be particularly pointed out in the appended claims.

In describing the invention in detail and *he particular physical embodiment selected to iii trate the invention reference is had to the accompanying drawing wherein like characters of reference designate like parts throughout the several views and in which:

Figure 1 is a longitudinal sectional view of physical embodiment of a fuse selected to illustrate the invention; Fig. 2 is a longitudinal sectional view on the plane indicated by the line II-II of Fig. 1, viewed in the direction of the arrows at the ends of the line; 3 a transverse sectional View on the plane indi ted by the line III-III of Fig. 2, viewed in the direction of the arrows at the ends of the line; Fig. 4 is a transverse sectional View on the plane indi by the line IV-IV of Fig. 2, viewed in the direction of the arrows at the ends of the line; 5 is a transverse-sectional view on the plane indicated by the line V-V of Fig. 2, viewed in the direction of the arrows at the ends of the line.

In order to illustrate my invention and the novel features thereof I have selected as a physical embodiment an enclosed type of fuse approximating in general outline and construction well (Cl. 20G-131) known fuses of the prior art, altering the same only insofar as is necessary to illustrate my invention and improvement.

The fuse employed to illustrate the invention is of the enclosed knife blade type. It consists in general of an outer hollow enclosing shell and an inner fuse link and distance bar or fuse link unit including protruding knife blades, one at each end thereof together with suitable closure members and means hereinafter known as screw caps for attaching the parts rigidly together.

In Fig. 1 numeral l designates a hollow cylindrical body forming the main portion of the enclosing casing. The body 1 may be made of a variety of materials. I prefer hard vfibre, sometimes known as bone nbre. Each end of the main body 1 is preferably provided with a metallic ferrule as 2. This ferrule is formed with internal crew threads 3 engaging with cooperating eX- ternal threads upon the body 1 and its denite 75 position lengthwise of the body 1 is determined by the presence of shoulder 4 abutting the end of the body 1. To render the union between the main body l and the ferrule 2 more secure I prefer to employ rivets 5 passing through the fer- 80 rules 2 and the main body l. The ferrule 2 is also provided with external screw threads 6 for cooperating with a cap 7 the particular function of which will be hereinafter more fully explained.

Protruding from each end of the enclosing body formed of the main body 1 and ferrules as 2 are knife blades as 8 and 9. In order to secure the

knife blades

8 and 9 in spaced relation I employ the distance body 10. This distance body may be made of various appropriate materials but my purposes I nd are best served by employing the same material that is used for the main body 1, that is, I preferably employ hard or bone nbre. In order to obtain a maximum of rigidity and best provide against distortion I prefer to employ the hard fibre 10 in the form of approximately a semi-circularshell. This approximate semi-circular form is best shown in Fig. 4. I also prefer to make the body 10 a somewhat less than a semi-circle so that the

faces

11 and 12, as best shown in Fig. 4 will not reach to or be adjacent the

edges

13 and 14 of a knife blade as 8.

In order to rigidly attach the body 10 to each of the

knife blades

8 and 9, I prefer to employ a semi-circular block 15, as best shown in Fig. 4. This semi-circular block 15 is interposed between kthe somewhat semi-circular hard nbre body 10 and the tang end of a knife blade and 110 then in order to secure the knife blade the block and the body 10 rigidly together I pass the

machine screws

16 and 17 through the semi-circular body 10, the block 15 and into screw threaded oriiices 18. By this construction I obtain a construction which is easy to assemble and which also may be easily disassembled merely by the use of a screw driver which inserted in the slot provided in all screws as 16 and 17 will readily remove these screws and allow the parts to be separated so that if necessary, by reason of darnage of excessive heat or otherwise, the hard fibre member 10 may be readily replaced. This block 15 may be made of hard or bone fibre, or a metal such as aluminum which does not retain a deposit of volatilized fuse metal thereon.

In order to provide for the maximum of free flow of volatilized metal and gases generated by the blowing of a fuse link I remove a maximum of the material of body 10 between the end of the tang of the blade 8 and the end of the tang of blade 9, as illustrated by 40 in Fig. 5, leaving in it an amount of material 10 found by experience to be suiiicient to act properly to space the

tongues

8 and 9 and prevent undue distortion or misalignment thereof.

I provide a threaded hole as 19 in each of the tangs of the

tongues

8 and 9 which threaded hole is adapted to receive a machine screw, as 20, for the purpose of fastening one'end of the fusible link 21 conductively to a knife blade. In connection with the screw 20, I employ an aluminum washer 22 which, as best shown in Fig. 4, is of such diameter that it more than completely covers the slotted end 23 of the fuse link 21. The purpose of using an aluminum washer is to prevent an appreciable .deposit of volatiiized fuse metal at this point and the reason for making the washer larger than the end of the fuse link is to protect as much as possible the end of the fuse link from a deposit of volatilized metal which would tend to solder the end of this link to the tang end of the knife blade. By this construction I am quite successful in preventing lsoldering of the brass machine screw 20 to the washer, the washer to the end of the fuse link and the fuse link to the tang of the knife blade. In order that there may be no impediment to the free passage of the machine screw 20 into threaded hole 19 in the tang of the knife blade I provide a through hole or orifice 24 in the block 15, best shown in Fig. 2, and in order to` be certain that nothing may lodge in this hole 24, I carry the cut away portion of the `body V10 up to a point as 25' and scarf block 15 as at 39, best shown in Fig. 2, which makes certain a clear passage through the tang of the blade, the block 15 and the body 10, and makes an arrangement which requires a minimum of longitudinal cutting of body l0.

In order to provide closures for the ends of the body 1 and at the same time allow me to form the knife blades, the fusible link and the distance body 10 as a unitary structure I make the closure arrangement for the two ends slightly different.

The closure for the end of the body 1 adjacent the blade 8 includes an aluminum washer 25 and a brass washer 26. The aluminum washer 25 has a slot therein through which the tang of the blade 8 may pass and the brass washer 26 has a like slot. The brass washer 26, however, abuts

shoulders

27 and 28 of the blade 8 so that both washers, after the

screws

16 and 17 are in place, are firmly held between the

shoulders

27 and 28 and the end of the body 10` and the end of the metallic block 15 although I prefer to also solder washer 26 to the blade. They aluminum washer 25 has several small projections as 29 formed in any appropriate manner thereon. These projections 29 rest against the end of the ferrule 2 and so slightly space aluminum washer 25 from the end of the ferrule 2.

The closure adjacent the knife blade 9 includes a brass washer 30 adapted to receive the tang of the blade. This Washer is by any appropriate means rigidly attached to the blade 9. It may be soldered thereto. This washer 30 abuts the shoulders 31 and 32 of the knife blade 9. In addition to the washer 30 there is a Washer 33 which has a slot therein through which the larger portion of the blade 9 may pass. This washer is not permanently attached to the blade 9.

In addition to the washer 30 there is also an aluminum washer 34 in the form of a shallow cup positioned on the inner side of the washer 30 and extending up along the sides thereof. This washer or shallow aluminum cup 34 protects the brass washer 30 against the deposit of volatilized fuse metal thereon. Although a rim is' preferred on the washer 34, it is to be understeed that this rim may be dispensed with.

In order to assemble the fuse the knife blades are connected by means of the body l0 as hereinbefore described and the fuse link 21. as put in place together with

washers

25 and 26 and 39 and 34 then with cap 7 removed this assembly is passed endwise through the body 1 whereupon the cap 7 passed ove;` the knife blade 8 and screwed home bringingl the projections 29 firmly against the ferrule 2 and the ange 36 against the outside surfaces of the washer 26. Then the washer 33 is passed over the knife blade which may be done by reason of the presence of the slot in the washer and afterwards cap 7 is placed over the washer and screwed home upon the ferrule 2. When this assembly has been made there is a slight space between washer 33 and the end of ferrule 2 and also a slight space between the wall of ferrule 2 and the cup washer 34 and in addition a slight space between the ends 37 of the caps 7 and the shculders 38 upon the ferrules 2. These spaces provide a free but tortuous path from the interior of the enclosing body 1 around through the screw threads 6 to the outside atmosphere for any volatilized gases and metals generated within the casing.

By the construct-ion hereinbefovre described I have provided an enclosed knife blade fuse which may be disassembled by removing two caps as 7 and one washer as 33 and then withdrawn as a unitary device with the

knife blades

8 and 9 with their associated parts. When

such blades

8 and 9 have been withdrawn the fusible link 21 may be easily replaced by loosening two machine screws as 2O inserting a new fuse link and tightening the screws and the whole may then be reassembled in the manner hereinbefore described., without the use of any tools whatsover. Furthermore, the internal construction is such that washer 25 is spaced from the end of ferrule 2 by the projection 29 and washer 33 is spaced from the end of ferrule 2 by reason of the definite length given to member l0 and a maximum of internal metallic parts which might be covered by a deposit of volatiliaed metal have been shielded by a material, preferably aluminum, which is resistant to deposit thereon of a volatilized metal.

Csi

By the construction hereinbefore described it is undoubtedly true that a greater portion of the fusible metal ofthe link will be turned into a gas than is customary ina fuse of this type but to provide for this contingency' I have cut away the greatest possible -portion of the body l0 so as to obviate any obstruction tothe free flow of the gases within the body 1 so that they may with the least resistance flow out at the ends around the end of the ferrules 2 and through the screw threads 6 to issue at the small space provided therefor between 37 and 38.

Although I have particularly described only one particular physical embodiment of my invention and explained the principle and operation thereof, nevertheless, I desire to have it understood that the form selected is merely illustrative but does not exhaust the possible physical embodiments of the idea of means underlying the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a unitary fuse link device, in combination:

.a somewhat semi-circular, elongated, insulating body formed with a longitudinal cut away portion; a some-what semi-cylindrical block positioned on each end of the body; knife blade tangs, one bearing upon the broad face of each semi- .cylindrical block; each of said tangs being provided with screw threaded orifices; machine lenclosing body surrounding the said parts and means for closing the open ends of said body and securing the said parts within the interior thereof.

.' 2. As a means for securing the tang end of 'a knife blade the combination of a knife blade tang having a broad face; a semicylindrical block having its flat face abutting the broad face of the tang, the said block being provided with an .orifice of major dimensions therethrough and 'with a plurality of orifices of minor dimensions therethrough; an insulating spacing body of approximately semi-circular form; machine screws passing through the said body and through the orifices of minor dimensions in the block 'and screw threaded into the tang end of the knife blade whereby the orifices of maj or dimensions in block aligns with the screw threaded orifice in the tang, said body being provided .with a longitudinal cut away portion extending `to and including the orifice of major dimensions in the block.

3. In an electric fuse, in combination: a hollow enclosing body; a fusible link therein; knife blades, one protruding from each end of theL 'hollow body; screws for connecting the ends of the fuse links to the knife blades; threaded ferrules, one upon each end of the hollow body; screw caps, one engaging each of the ferrules; a

.closure washer at one end of the hollow body, vsaid -closure provided with projections spacing it from the end of the ferrule; a flange on the screw cap cooperating with the closure to hold the projections firmly against the end of the ,ferrule whereby Volatilized metal and gases blades, each provided with shoulders and each 'provided with tangs; a distance body intermediate the knife blades, said distance body being formed of insulating material and arcuate in transverse section, the chord of the arc being spaced throughout to the same one side of the parallel surface of the tangs, and formed with a longitudinal cut away portion of such extent as to leave a relatively slight amount of material at the ends thereof and means for connecting the distance body and the knife blades.

.5. As a fixed spacing means for the knife blades of an enclosed cartridge fuse of the knife blade type the combination of an insulating body arcuate in transverse cross-section extending from knife blade to knife blade and formed with a longitudinal cut away portion extending a substantial distance under each tang and a semi-cylindrical block having its curved surfaces tted into the concave surfaces of the arcuate body adjacent the end thereof and its flat face bearing against a broad face of a tang together with machine screws passing through the arcuate body and the block into the knife blade tang.

6. As an end construction for a knife blade fuse of the enclosed cartridge type the combination of a knife blade formed with a tang and shoulders, of washers surrounding the tang and bearing against the shoulders and an insulating distance body bearing against the Washers preventing endwise movement thereof together with a block interposed between the distance body and f the tang and means fastening the distance body, the block and the tang securely together, the distance body, tang and block formed with aligning orifices.

'7. In an enclosed cartridge fuse of the knife blade type the combination of a knife blade having a tang and formed with a screw threaded orice therein for the reception of a capscrew for holding the end of a fuse link, of semi-cylindrical blocks provided with an orifice aligning with the screw threaded orifices in the tang, the curved surfaces thereof bearing against the distance body and means passing through the distance body and the block and the tang for securing the block, the body and the tang together with the said distance body provided with an orifice situated in alignment with an orifice in the block whereby a through opening is provided below the cap screw in the tang.

8. In an enclosed electric fuse of the knife blade cartridge type having a knife blade protruding from each end thereof, a distance body for spacing the knife blades a fixed distance apart, said body being formed arcuate in transverse cross-section and with a longitudinal cut away portion for the greater portion of its length and means including slotted washers and flanged screw caps for closing the ends adjacent the knife blades and for holding said knife blades in place.

9. In an electric fuse of the enclosed cartridge type having a knife blade protruding from each end thereof, as a means for providing a free but tortuous path for the flow of volatilized metal and gases from the interior of the fuse to the atmosphere, the combination of a ferrule formed with an external screw thread positioned on the end of the cartridge, of a slotted substantially inflexible washer surounding a knife blade and a substantially similar size washer, formed of aluminum, provided with projections in the face thereof adapted to bear against the end of the ferrule positioned between the first mentioned washer and the end of the ferrule and an inte-rnal threaded flange cap threaded upon the ferrule with the flange thereof bearing against the ide rst mentioned Washer whereby the' projections o n the second mentioned washer are held firmly in contact with the end of the ferrule.

10. In an electric fuse, in combination: a hollow cylindrical body of insulating material; ex-

ternal threaded ferrules, one upon each end of the hollow body; knife blades, one protruding from each end of the hollow body; a slotted Washer provided with projections in the `face thereof surrounding and held in position on one o f the knife blades; a slotted Washer surrounding and held in position upon the other knife blade, said washer being of a diameter such that it may be passed through the hollow body; a removable slotted Washer surrounding the same knife blade as the last mentioned washer; an insulating distance body attached at opposite ends, one to one of said knife blades and the other to the other of said knife blades and of such length that the projections on the first mentioned washer may bear tightly against the end of the ferrule adjacent thereto and the remQV- able washer on the other knife blade Will at the same time bear tightly against the second mentioned washer, and internally threaded flanged caps for cooperating with the threaded ierrules and the said washers to hold all parts firmly togelther, l

11. In an electric fuse, in combination; knife blades, each provided with shoulders and each provided with tangs; a distance body intermef diate the knife blades, said distance body being formed of insulating material and arcuate in transverse section, the chord of the arc being spaced throughout to the same one side of the parallel surface of the tangs; and means for connecting the distance body and the knife blades.

FRANK C. LA MAR.