US738874A - Electric fuse. - Google Patents

Description

No.738,874. PATENTED SEPT. 15, 1903.

G.B.BABY.

ELECTRIC FUSE.

APPLICATION FILED MAY 2, 1903.

K0 MODEL.

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Uivrrnn Frames Patented September 15, 19 03 Far-mar FFICE.

ELECTRlC FUSE.

SPECIFICATION forming part of Letters Patent No. 738,874, dated September 15, 1903.

Application filed May 2, 1903.

To all whom it may concern:

Be it known that I, GEORGE Benson BABY, a citizen of the Dominion of Canada, residing at the city of St. Oatharines, in the county of Lincoln, in the Province of Ontario, Canada, have invented certain new and useful Improvements in Electric Fuses; and I do hereby declare that the following is a full,

clear, and exact description of the construction and operation of the same.

Fuses of the class specified are used on switchboards to prevent injury to electric machines from overloads or short circuits, and it will be observed that dynainos used for incandescent lighting maintain a constant pressure. Hence if the outside resistance be reduced to a very low value, as it would be in the case of a short circuit, a large rush of current would be the result. Short'circuits may thus cause considerable damage unless the circuit is promptly opened, which is very seldom the case. Therefore a fuse is required that will blow without arcing, and my improvements in fuses are calculated to accomplish that result.

My invention consists, first, of two brass rods, one longer than the other, each provided with a square projection near the outer end and threaded above and below the said projection, the latter made to fit in a corresponding square opening in a disk and cap, preferably of annular form, the outer ends of the said rods made to project a short distance through each head or cap and screwed into a tapering terminal. Each inner end of the said brass rods has a hole drilled therein to receive the ends of a fuse-wire, which is soldered thereto. Second, the said rods and fuse-wire are inclosed in a cylindrical glass case, formed at each end with an outwardlyprojecting annular rim, which is made to rest in a corresponding seat of an annular collar, which is screw-threaded on the outside, over which a head or cap is screwed, a rubber washer being interposed at each end between the glass rim and collar and between the rim and metallic disk and between the disk and cap, as will be more fully shown hereinafter. The glass case is partly filled with mineralseal oil, high enough to cover the lower end Serial No. 155,256. (No model.)

of the upper brass rod. A11 air-opening is made in the top to allow air to escape, which prevents the breaking of the glass case when the fuse blows. I

Reference being made to the accompanying drawings, Figure l is an elevation of an electric fuse embodying my invention. Fig. 2 is a cross-section of the same. Fig. 3 is a side elevation of the upper and longest brass rod. Fig. 4 is a top view of the same. Fig. 5 is a perspective view of the upper head or cap detached. Fig. 6 is a plan of the upper copper disk. Fig. 7 is an edge View of'the same. Fig. 8 is a plan of the lower rubber washer, showing square central opening. Fig. 9 is an edge view of the same, showing thickness. Fig. 10 is a plan and edge view of the extra rubber washer on the bottom copper disk. Fig. 11 is a crosssectio'n of the upper collar, showing seat for glass cylinder. Fig. 12 isa similar view, but showing the lower collar.

terminal, a side view of which is shown in Figs. 1 and 2. Fig. 14 is a top view of the upper terminal, a side view of which is shown in Figs. 1 and 2. w

Similar letters refer to similarparts throughout the several views.

A represents a brass rod provided near it upper end with a square projection b, as shown at Figs. 2 and 3 and a. Itis also screw threaded above and below the said projection 19. The latter is made to fit in a correspond ing square opening 0 in a circular head 0 and alsoin a square opening a in a copper disk B an d circular rubber washer d. A metal terminal, as E, Figs. 2 and 14, is screwed on the top projecting end of the said rod A, and the threaded nut D is screwed on the rod under the disk F to hold the aforementioned parts together. The square projection b in the corresponding square openings of the head, disk, and washer prevents the rod from turning when the terminal is screwed on the rod. A, Fig. 2, represents a similar brass rod to the upper one described, only shorter, and also provided with a square projection 13, made to enter and to fit into a corresponding square opening 0 in the head 0, rubber Washer d,

and copper disk F, with a terminal E screwed Fig. 13 represents an end View of the bottom on the outer end of the said rod and a nut D screwed on the opposite side, with a rubber washer e interposed between the said nut and the copper disk E" to hold the parts tightly together and make themv fluid-tight.

The longer upper rod A and the lower and shorter one A are connected together with a fuse-wire B, which is inserted in drilled holes in the end of each rod and soldered therein.

The top and bottom parts are held together by means of a cylinder G, which preferably may be of any transparentsubstance, as glass, and a seated collar K at the top and K at the bottom, each of which is provided with an annular seat f, formed on the top and bottom edges,respectively, of the said collars,-the said glass cylinder having a flange a at the top and bottom which rests in the said seat of each collar. The said collars (which preferably may be of hard vulcanized fiber or hard rubher) are screw-threaded on the outside, and the collars are made to encircle the glass case, and the top and bottom flanges a of the cylinder G are made to rest in the said seats fof the collars 7c and with a rubber washer g above it and one, h, below it, and the heads 0 and O, which are threaded on the inside, are screwed on the collars. An air-opening p is made in the top head 0, disk, and rubber washer, and a small tube Q, of brass, will be made to pass through the openings and be screwed into the metal disk F. The object of this vent is to allow the air to escape when the fuse blows from any cause which would throw the oil upward and expel the air, preventing the bursting of the glass cylinder. The oil falling back again after the fuse blows extinguishes the arc and prevents the current from arcing, thus preventing injury to the electric machines and switchboards from short circuits or overloads.

It will be observed that the collars K and K are also provided each with an inner annular projection t' around the inside lower edge of the top collar K and a similar annular projection 2" around the top inner portion of the lower collar, as shown more fully in Figs. 11 and 12. These annular projections are for the purpose of keeping the collars steady in place on the cylinder.

' The top electrical terminal E and the bottom one, E, are each screwed on the respective ends of the brass rods A and A. The top one, E, is of a slightly-different form to the lower one, having a slot J and a tapering elongation,slightly wedge-shaped,to enter a corresponding socket on the switchboard. This enables the said top terminal to be thrown in and out of electrical connection.

The bottom terminal E is of a different form,

but has a downward taper t0 fit in a corresponding socket attached to the switchboard to hold the device in place and still form electrical connection.

It may be here stated that when the fuse Having thus described my device and its advantages, what I claim as my invention, and desire to secure by Letters Patent, is-

1. In an electric safety-fuse, two brass rods placed vertically in alinement, the upper one longer than the lower one, both formed with a square or other shaped projection near the outer end of each, and threaded above and below the said projection, the inner ends of the rods made to receive the ends of the fuse- Wire, and inclosed in a glass cylinder containing mineral-seal oil or other non-conducting oil, and formed with an outward flange at each end, and two outwardly-threaded annular collars made to surround the cylinder at each end respectively, both having an annular seat to receive the flanges of the cylinder, an annular top and bottom cap made to screw on the said collars respectively, terminals screwed on the outer ends of the said rods which project through the caps, and inside nuts on each rod to hold a washer and metal disk in each cap, substantially as and for the purpose specified.

2. In an electric fuse, two vertical rods, with a fuse-wire connecting each, a square or other shaped projection on the said rods, caps with square central openings to receive the projections on the rods, a glass cylinder containing mineral-seal or other non-conducting oil sufficient to submerge the fuse, a washer placed under and over each flange of the glass cylinder, a metal disk with central square opening placed over the top of the cylinder and a washer placed on the same, a

vent-pipe screwed into the said disk and passing out at the top of the upper cap, substantially as specified.

3. An electric fuse consisting of two rods placed vertically in alinement, the upper one longer than the lower one, with a fuse-wire connecting each, inclosed in aglass case, the same containing a mineral-seal or othernonconducting oil, a collar made to surround the said reservoir at each end with seats for the outwardly-turned flanges of the reservoir, a rubber washer placed under each flange, and one above it, a copper disk having a square opening to receive the square projection of the top rod, and an air-gap into which a tube is inserted through a corresponding opening in the top cap, and a nut on the inside screwed ICO on the top rod to hold the disk and Washer gap pipe in the top cap communicating with above it in firm position, substantially asand the interior of the case, terminals secured to for the purpose specified. the two rods, all constructed and arranged 4. In an electric safety-fuse the combinasubstantiallyas and for the purpose specified. 5 tion of two rodshavingafnse-Wire connection Dated at Hamilton, Ontario, Canada, the 15' with each inclosed in a glass case provided 25th day of April, 1903.

with end flanges, and partially filled With GEORGE BENSON BKBY. mineral-seal or other non-conducting oil, a In presence of threaded collar encircling each end of the JNO. A. BABY,

I0 case, a cap screwed on each collar, an air- WM. BRUCE.

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