US1419724A - Inclosed fuse - Google Patents

Description

A. L. EUSTICE.

IINCLOSED FUSE.

APPLICATION FILED MAR. 7, 191a.

Patented June 13, 1922.

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UNITED STATES ALFRED L. EUSTICE, OF CHICAGO, ILLINOIS.

Incnosnn FUSE.

T 0 all to 710m it may concern Be it known that I, ALFRED L. EUsTron, a citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Inclosed Fuses, of which the following is a specification.

This invention relates to inclosed fuses.

One of the objects of the invention is to prevent any operative association of the metal of the fusible element after the latter has been melted.

Another object is to improve the means for confining a given portion of a fusible member within an air space to obtain greater sensitiveness in the melting of the fusible member.

Generally speaking, these and other objects are accomplished by providing in a fuse, the combination of a closed casing, a fusible element mounted therein and electrically connected exteriorly of thecasing, and separable members forming an air space around a portion of the fusible element to increase its sensitiveness and to prevent any operativeassociation of the metal of the fusible element after. the latter is melted.

The invention is illustrated on the accompa nying sheet of drawings, in whic'h--.

Figure 1 is a longitudinal sectional view of a fuse embodying my invention;

Figure 2 is a transverse sectional view taken in the plane of line 22 of Figure 1;

Figure 3 .is a longitudinal sectional view of the same fuse'taken at aidifferent angle from that shown in Figure 1; V

Figure f is a transverse sectional. view taken in the plane of line i 1 of Figure 3.;

Figure 5 is a perspective view of one of the semispherical members for enclosing a portion of the fusible element; and,

Figure 6 is a perspective view of an insulating member interposed betweentwo semispherical members.

The various novel features of my invention will be apparent from the following description and drawings and will be particularly pointed out in the appended claims. i

Referring to the figures of the drawings, it will be noted that I have provided a fuse which includes a cylindrical casing 10, preferably formed of insulating material, the ends of the casing being closed by metallic electrical conducting caps, 11. Terminal straps 12, which extend diametrically Specification of Letters Patent.

ment.

Patented June 13, 1922.

Application filed March 7, 1918. Serial No. 220,962.

through the casing 10, are electrically connected with the conducting caps 11. Connecting the terminal straps 12 is a fusible element or member 13, the ends of which may be secured to the terminal straps 12 in any suitable manner. In this particular instance the ends of the fusible element 13 are secured to the terminal straps 12 by screws 1 f.

As is customary in this type of fuse, the

casing 10 is filled with any suitable amount of non-conducting material 15, preferably in a pulverulent or finely powdered state, such as asbestos, plaster-of-Paris or slaked lime,

adapted to dissipate the heat and provide minute paths or interstices for the escape of the vapor or gases arising or evolved upon the melting of the fusible element.

It has been found that when the fusible element 1s packed in the insulating material,

as .hereinabove described, it sometimes happens that after the fusible element has been melted there is still an operativeassociation of the metal of the fusible element, which permits passage of current therethrough,

and, as a matter of fact, the fusible element may .become so mixed with the packingmaterlal as to cause the resistance of the fusible element to be materially altered, there by defeating the very object of the safety fuse.'

This undesirable feature is overcome by placing a protecting enclosure around'a portion of the fusible element by providing a plurality of. semispherical members, 16, which fit over a portion of the fusible eleslipped over the ends of the fusible element Each of the semispherical members 1 3 before the latter has been secured to the r with each other by acentrally arranged in sulating disk 18, also plOVIClBClWltll an aper- By means of the cooperative association of the semispherical members 16, an air space 1S formed,,wh1ch 111 this case is around the central partof the fusible element 13.

Tnthis manner. the heat which is generated by current passing through the fusible eleterminal straps 12., These semispherical members are held out of electrical contact 'Q ough which the fusible element eX- tends. These separable semispherical me ment is retained in the air chamber 19, thereby making it possible to determine with a great degree of nicety the load which will cause the melting of the fuse. The radiation also under these conditions is maintained constant, which greatly adds to the sensitiveness of the arrangement in question.

The semispherical members 16, preferably are of hardened metal to prevent substitution of the fusible element after it has been melted. A further advantage of such an arrangement is that it makes possible the prevention of the establishment of any electrical connection between the ends of the closed casing after the fuse element has blown. The metal members are of such material as to prevent a foreign substance from being driven therethrough. Furthermore, the insulating disk interposed be tween the separable members forming the hollow portion about the fusible member prevents the melted fusible member from permitting electrical. connection after the same has blown. It would be rather difficult, if not impossible, to drive a nail through the member 16 to bridge the separate ends of the melted fusible member or to bridge the terminal straps 12. The members 16 also would act to deflect any object coming in contact therewith if it was attempted to drive that object through said members.

It is apparent that there may be various modifications of the invention herein particularly shown and described and it is my intention to cover all such modifications which do not involve a departure from the spirit and scope of the invention as defined by the following claims.

I claim:

1. In a fuse, the combination of a closed casing, a fusible element mounted therein and electrically connected exteriorly thereof, and complementary semispherical mem bers forming an air space around a portion of the fusible element to increase the sensi tiveness of the latter.

2. In a fuse. the combination of a. closed easing, a fusible element mounted therein and electrically connected exteriorly there of, and an apertured hollow member through which the fusible element extends and by means of which an air space is formed around the fusible element to increase the sensitiveness thereof, said hollow member being shaped to present deflecting surfaces toward the ends of said casing.

3. In a fuse, the combination of a closed casing, a fusible element mounted therein and electrically connected exteriorly thereof, a plurality of associated conducting members forming an air space around a portion of the fuse to increase the sensitiveness thereof, and an insulating medium between said associated members to prevent current passing from one member to another.

4t. In a fuse, the combination of a closed casing, a fusible element mounted therein and electrically connected exteriorly thereof, a plurality of associated conducting members forming an air space around. the fusible element to increase the sensitiveness thereof, and an insulating member separating said members to prevent the passage of current therethrough, all of said members having apertures through which the fusible ele ment extends.

5. In a fuse, thecombination of a closed casing, a fusible element mounted therein, and a hard deflecting shell within the casing enclosing an intermediate portion of said fusible element.

6. In a fuse, the combination of a closed casing, a fusible element mounted therein, and deflecting means of relatively hard material within said casing enclosing an intermediate portion of the fusible element.

7. In a fuse, the combination of a closed casing, a fusible element mounted therein and electrically connected exteriorly thereof, complementary semispheri all members form ing an air space around a portion of the fusible element to increase the sensitiveness of the latter. and an insulating" disk separating said semispherical members to prevent establishment of electrical connections therebetween by the metal of the fusible element after the same has melted.

S. In a fuse, the combination of a closed casing, a fusible element mounted therein. and a hard deflecting shell within the wasing enclosing an intermediate portion of said fusible element, said shell being provided with an apertured diaphragm of non-conducting material.

In. a fuse, the combination of a closed casing. a fusible element mounted therein. and a hard deflecting shell within the casing enclosing an intermediate portion of said fusible element. said shell being divii'led transversely of said fusible clement by an insulating member. I

10. In a fuse, the con'ibination of a. closed casing, a fusible element mounted therein. and a hard deflecting shell wit-bin said casing enclosing an intermediate portion of said fusible element. said shell being divided transversely of said fusible element by an insulating member, said insulating member having a portion for preventing electrical. communication through the material of said fusible element after same has been melted.

Signed at Chicago, Illinois, this 21st day of February, 1918.

ALFRED L. EUSTIGE.

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