US2271729A - Fuse plug - Google Patents

Description

Feb. 3, 1942 J. BALDWIN ET AL 2,271,729

FUSE PLUG Filed May 6; 1941 INVENTOR-S: Jo/m Baldwin BY Wi/Zl'am fil'lienrana MJ/T- M...

AT URNEY Patented Feb. 3, 1942 UNITED FUSE PLUG John Baldwin, Brooklyn, and William Hillenbrand, Rigo Park, Long Island, N. Y.

Application May 6, 1941, Serial No. 392,060

2 Claims.

This invention relates to fuse plugs and more particularly to a fuse plug having a mechanical indicating means to indicate that the fuse has blown out.

In accordance with the invention I provide a fuse plug having an indicating member that does not form a part of the electric circuit. The indicating member consists of a rod that is slidable in an aperture in the fuse cover. The rod is normally retracted by a light spring into the hollow interior of the fuse. The fuse wire is connected with a spring which is normally tensioned. When the fuse wire breaks, the spring is released and forces the indicatin rod outwards to indicate that the fuse has blown out. Since the indicating member does not form part of the electric circuit it is never alive and hence cannot cause an electric shock.

It is among the objects of the invention to provide an improved fuse plug having an indicating member for indicating that the fuse has blown out, said indicating member being insulated from the electric current flowing through the fuse.

These and further objects of the invention will become more apparent in the following description of a preferred embodiment of the invention illustrated in the drawing, wherein:

Fig. 1 is a longitudinal sectional view of a fuse plug of the invention,

Fig. 2 is a longitudinal sectional View similar to Fig. 1 showing the fuse plug in its blown out position.

Fig. 3 is a top plan View of the fuse plug of Fig. 1.

Referring to the drawing, the fuse plug in accordance with the invention comprises an insulating body III having a cover plate II provided with a central aperture I2. Insulating body III consists of two portions A and B separated along lines 8 and 9. Line 8 divides cover plate II into two parts. Portion A also includes the bottom of insulating body I being separated from portion B by line 9. This construction facilitates the assembly of the fuse plug of the invention. Insulating body I0 is threaded and engages with threaded sleeve I3. Sleeve I3 consists of an electrically conducting material and serves to hold together insulating portions A and B. Threaded sleeve I3 forms one of the two terminals of the plug. The other terminal is formed by center contact I4. Insulating body I0 is formed with an interior chamber I5. Center contact I4 and threaded sleeve I3 are electrically connected by spring I6 and fuse wire II arranged Ill in chamber I5. Spring I6 may be soldered to threaded sleeve I3 as indicated at I8. Insulating body I0 has a passage 20 arranged below cover I I through which spring I6 passes. Fuse wire I! is connected with central contact I4 by metal tape 2|. Rod 22 integral with disc 23 is slidable in aperture I2. Rod 22 and disc 23 are made of electrically insulating material. Spring 24 is provided between disc 23 and cover II and normally presses rod 22 into chamber I5.

The operation of my improved fuse plug will now be apparent. In the position of Fig. 1 rod 22 is nearly flush with the surface of cover II due to the action of spring 24, When fuse wire I'I breaks, spring I6 is released and presses against disc 23 to force rod 22 out of cover II. Spring 24 is comparatively light so that a small force is sufficient to bring rod 22 in the position of Fig. 2. Passage 20 may be closed by solder I8.

Various changes and modifications may be made to the details of construction of the in vention without departing from the broader spirit and scope thereof, as set forth in the following claims.

I claim:

1. A fuse plug comprising an insulating housing including a cover and consisting of two sections, one housing section comprising substantially one half of said cover and a semi-cylindrical portion, the other housing section comprising a base, the other half of said cover and a second semi-cylindrical portion, said two semicylindrical portions having an outer thread, a center contact on said base, a metallic threaded sleeve arranged for cooperation with the thread on said semi-cylindrical portions and forming a second contact, an insulating indicating member slidable in an aperture in said cover, a first spring urging said indicating member into said housing and away from said cover, a fuse connected with said center contact, a second spring connected with said fuse, extending through a transversal opening in one of said semi-cylindrical portions and connected with said sleeve, said second spring being normally tensioned by said fuse and being arranged to force said indicating member out of said cover when said fuse blows.

2. A fuse plug comprising an insulating housing including a cover and consisting of two sections, one housing section comprising substantially one half of said cover and semi-cylindrical portion, the other housing section comprising a base, the other half of said cover and a second semi-cylindrical portion, said two semicylindrical portions having an outer thread, a

center contact on said base, a metallic threaded sleeve arranged for cooperation with the thread on said semi-cylindrical portions and forming a second contact, an insulating indicating member slidable in an apetrure in said cover, a first spring urging said indicating member into said housing and away from said cover, a fuse connected with said center contact, a second spring connected with said fuse, extending through a transversal opening in one of said semi-cylindrical portions and connected with said sleeve, said second spring being bent to present a loop having substantially parallel portions arranged adjacent said transversal opening, said second spring further having a curved portion situated between said fuse and said loop and below said indicating member, whereby when said fuse blows said second spring forces said indicating member out of said cover against the action of said first spring.

JOHN BALDWIN.

WILLIAM HILLENBRAND.

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