US1469767A - Fuse - Google Patents

Description

Oct. 9 1923. 1,469,767

J. c. 'BOGLE FUSE Filed Oct. 10 1919 Patented Oct. 9, 19 23.

v UNITED STATES PATENT OFFICE.

JOHN C. BOG-LE, 01 OAK PARK, ILLINOIS, ASSIGNOB '10 FRANK B. COOK COIPANY, OI

\ CHICAGO, ILLINOIS, A CORPORATION 01 ILLINOIS.

FUSE.

Application filed October 10, 1919. Serial No. 829,780.

To all whom it may concern:

Be it known that I, JOHN C. Boom, a citizen of the United States, residin at Oak Park, in the county of Cook and tate of Illinois, have invented new and useful Improvements in F uses, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, formlng a part of this specification.

This invention relates to fuses and more particularly to an enclosed fuse employed in systems in which the apparatus must be protected against low amperage currents such for example, as telephone and telegraph systems.

The construction of enclosed fuses of low amperage ratings due .to the fineness and extremely delicate characteristics of the fuse wire used, is an extremely tedious and quite expensive operation.

The production of an enclosed fuse in which the use of the low amperage fuse wire is dispensed with and which at the same time will operate to introduce a long rupture in the circuit when the fuse is blown, would consequentl eliminate the principal manufacturing di culty which is met in the construction of enclosed low amperage fuses.

Likewise enclosed low amperage fuses, of the ordinary type now used commercially, are not very accurate and cannot be depended upon to blow and open the circuit at the specified amperage rating. This difiiculty arises from the fact that when the enclosed fuse wire is heated, due to the passage of current theretlirough, the fuse wire will expand and elongate. The fuse wire suspended in the enclosure due to thisgelongation, will make contact with the sides of the said enclosure which will obviously dissipate some of the heatgenerated in the fuse. This dissipation of the generated heat in this manner will naturally change the fusing point of the enclosed fuse wire.

One of the objects of this invention there Another object resides'in the roduction.

of an improved low amperage so which will cause an extended rupture in the circuit when the fuse is blown on the low amperage rating and which will cause a rupture of greater length when heavy amperage currents well above the rating of the fuse proper traverse the circuit.

A further object resides inthe roduction of an accurate and eflicient fuse or protection against low amperage currents Other objects of the invention will become apparent from the following description and accompanying illustrations, and the appended clams.

For the purpose of description, one arm bodiment of the invention is illustrated in the accompanying drawings in which- Figure 1 is a plan view of the com lete tubular fuse and Fig. 2 is a longitu incl section of the fuse.

As illustrated in the drawings the enclosed fuse comprises a c lindrical or tubular member 4, preferab y constructed of fiber, rubber or some other hard insulating substance, the tube bein utilized to protect the fuse wire enclosed t erein. Secured to either end of the enclosure 4 are metal ca or terminals 5 and 6. Thesecaps may secured to the tube 4 in any desired manner the end of the cap 6, t e solder 9, serving to permanently secure one end of the fuse wire 8 to the inner wall of the cap 6-.

The cap 5 is likewise fitted with a cylindrical opening in which a solder plug 10 is positioned. This solder serves to secure one end of a spiral spring 11, to the inner wall of the cap 5. The spring 11 is composed of some good conducting metal preferably phosphor bronze.

sprin 11. is secured to .the fusewire 8,:by a

fusible-alloy 12, the fuse rating of which is .10

The other end ofPthe equal tothe'amperage rating of the spring 11, connected to the fuse wire 8, by means of the fusible alloy 12, are positioned inthe fuse enclosure 4, bymeans of the 01- This fuse pro r. V 7 gen the fuse wire 8 and its. associated der plugs 9 and 10, the spiral spring 11 is held in tension. To assemble the fuse wire 8 and its associated spring in the enclosure 4 in this manner the cylindrical openings of the metallic end caps or terminals 5 and 6 are made large enough so as to readily and conveniently pass the spiral spring 11, therethrough.

In assembling a fuse of this type, the enclosure 4 is first fitted with the metallic caps or terminals 5 and 6. The fusible element comprising the spiral spring 11 and fuse wire 8 interconnected by the fusible alloy 12 are next assembled; he spring and fuse assembly is then slipped through the opening in the end cap 6, and the end of the fuse wire 8 is then soldered to the said cap by means of the solder plug 9. lVhen the fuse wire is thus attached to the cap 6, the other end of the fuse and spring assembly interconnected by the fusible alloy 12 will project from the fuse enclosure out of the cylindrical end opening of the other cap 5. A slight tension is now exerted on this projecting end of the spring 11' which will place the spring under tension, and when the spring is in this condition, the solder plug 10 is run into the cap 5 to secure this end of the spring to the cap 5 and retain the spring 11 under tension.

The metal end caps or terminals attached to the fuse enclosure 45 illustrated in the drawings are used in conjunction with contact springs in fuse housings which are well known in the art. Obviously any other type of end terminal could be used and these terminals could likewise be readily fitted with threads and nuts to receive wires or any other end connection.

When a fuse'of the type hereinbefore described is placed in circuit and a current traverses the fuse which has an amperage equal to the normal rating of the fuse proper, the fuse wire 8, spring 11 and; fusible alloy 12 will have been raised in temperature to the fusing point of the fusible alloy 12. Consequently the interconnection between the fuse wire 8 and the spring 11 will be interrupted due to the tension of the spring 11 and this in turn will interrupt the circuit in which the fuse proper is inserted; Fusing of the fusible alloy 12 and the rupture of the circuit at the junction between the fuse wire 8 and the spring 11 will cause an extended gap in the circuit, because of the tension in the spring, and consequently as a result of this extended gap, no arcing between the ends of the interrupted circuit will be ossible.

hen a current of abnorma amperage traverses a fuse of this character, it will be evident that the fuse wire 8 as well as the fusible alloy 12 will be fused by the heavy character an extended ga will be introduced into the circuit. his gap will be substantially the e uivalent to the length of the fuse wire 8. urthermore, when, due to the passage of current througlrthe fuse wire 8, the said fuse wire expands and elongates, the elongation of the wire will be taken up by the spiral spring or yielding member 11. Elongation of the yielding member 11 will be practically negligible because of the low resistance and high conductivity of the metal of which the spring is .made. The spring 11 consequently prevents the. fuse wire 8 from sagging in the fuse enclosure 4, inasmuch as any elongation of the fuse wire 8 is immediately taken up by the spring and the fuse wire is retained in suspension as shown in Figure 2 at all times. This co-operative action between the fuse wire 8 and the spring 11 prevents contact between the, fuse wire 8 and the enclosure 4 due to fuse wire elongation, and therefore increased dissipation of the heat generated in the fuse wire, due to contact with the fuse wire enclosure, is prevented. This will obviously increase the accuracy of the fuse in view of substantially constant heat radiation from the heating member or fuse 8, and therefore fuses constructed in this manner. can be readily constructed and adjusted to blow or fuse at 'the rated amperage capacity of the fuse.

It will be evident from the foregoing description that fuses constructed in accordance with the teachings of this invention are adapted for the protection of circuits against low amperage currents and that these fuses are readily constructed without meeting the manufacturing and assembling difficulties ordinarily encountered in the handling and using of fine, fragile fuse wire of a rating of one ampere or less. A fuse construction of this kind is consequently much more substantial than a fuse in which the low amperage fuse wire is threaded from one terminal to the other. Likewise, the fuse construction is such as to result in a fuse which can be accurately rated even for low amperage ratings. Obviously, this invention is not limited to the specific embodiment herein illustrated and described but is capable of other applications and many variations within its sprit and scope as set forth in the following claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is- 1. As a new article of manufacture, a fuse of low amperage rating, comprising in combination, a fuse wire of higher amperage rating than the fuse proper, a resilient means, and a fusible alloy connecting said fuse wire and resilient means, said alloy being eliminated as a necessary conducting part of the electric circuit but fusing at the lllf) lll) amperage ratin' of the fuse proper by? reason of the oat developed by' current flow thru the fuse wire and resilient means.

2. As a new article of manufacture, a fuse of low amperage rating comprising in com bination, a fuse wire of an amperage rating higher than the amperage rating of the thereof adapted to be connected to said-fuse wire and the other end being connected to the other terminal, and means being eliminated as a necessary conducting part of the circuit for interconnecting said fuse wire and said yielding means which operates to cause an extended gap in the circuit when a low amperage current of the rating of the fuse proper traverses the circuit.

4. As a new article of manufacture, a fuse of low amperage rating, comprising in combination, a fuse-wire of an. amperage rat: ing higher than the amperage rating of the fuse proper, means being eliminated as a necessary conducting part of the circuit but operable to initially rupture the circuit when current of the am erage rating of the fuse proper traverses t e circuit, thesaid' fuse wire of higher amperage rating being fused when a current of substantially higher amperage than the amperage rating of the fuse proper traverses the circuit thereby increasing the length of the initial rupture in the said circuit.

5. As a new article of manufacture, a fuse of low amperage rating, comprising in combination, an enclosure, fuse .terminals connected to both ends of said enclosures, a fuse wire of higher amperage rating-than the rating of the fuse connected to one of said terminals and enclosed in said enclosure, a yielding means having one end thereof adapted' to be connected to said fuse wire and the other end being connected to the other fuse terminal, the yielding-means being likewise confined in said enclosure, and

means being eliminated as a necesary part.- 'of the circ'uit'for interconnecting said fuse.

wire and theend of said yielding means butoperable to cause-an extended gap in the circuit when a low amperage current of the rating of the fuse proper traverses the cir- Clllt'.

6. As a new article of manufacture, afuse of low amperage rating, comprising in combination, a fuse enclosure, fuse terminals connected to both ends of said enclosure, a

either end of said enclosure, and said con- 1 place the said nection-being made so as to spring under tension.

' 7. s a new article of manufacture, a fuse of low amperage rating comprising in com bination, a fuse wire of an amperage rating higher than the amperage rating of the fuse proper, a yielding means, a' fusible alloy being eliminated as a necessary part of the circuit and mechanically interconnecting said fuse wire and said yielding means, said alloy fusing at' the amperage rating of the a fuse proper, the said yielding means being adapted to keep the fuse wire in tension and take up elongation thereof due to heat expansion. l

8. As a new article of manufacture, a fuse of low amperage rating comprising in combination, a fuse enclosure, fuse terminals associated with the ends of said enclosure, a

fuse wire of higher amperagerating than "the rating of the'fuse proper connected to one of said terminals, a yielding means havinone end thereof adapted to be connecte to said fuse wire and the other end" lng means acting to keep the fuse wire in r before the fuse is blown and to cause an extension and suspended in the fuse enclosure tended gap in the circuit when the fuse is blown. Y f

.In witness whereof, I .have hereunto subscribed my name. I I

"JO/Hi c. BOGLE.

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