US2852641A - Flashproof fuse plugs - Google Patents

Description

Sept. 16, 1958 G. w. VALENTINE 2,852,641

FLAsHPRooF FUSE PLUGS Filed Dec. 9, 1955 INVENTO gow/anya en lne.

United States Patent FLASHPROOF FUSE PLUGS Garden W. ValentineyOwosso, Mich. Application December 9, 1955,Serial1No. 552,107 3 Claims. (Cl. 20d-130) Thisinvention relates to electrical :plug fuses such as used in electric circuits to 'form a safety link and open the circuit when too much current is flowing through the line, a short circuit occurs, or there is a sudden rush or surge of current of dangerous proportions.

The principal object of the invention is to design a sealed-in ashproof plug fuse which smothers any flash or explosion caused by a short circuit, poor contact, or surge or overload of current of dangerous proportions in the circuit.

Another object of the invention is to provide a very simple, practical, and inexpensive sealed-in ashproof plug fuse which can be readily manufactured and assembled, and which in general appearance is substantially the same as the plug fuse at present on the market.

Still `a further object is to design a llashproof plug fuse in which the 'fuse element is embedded in an insulating material eliminating accident hazards, by smothering any liash or spark which might produce a fire when there is a poor connection, the plug fuse loosely mounted and/ or overloaded.

A furtherobject still is to provide a flashproof plug fuse provided with a sealed-in insulating material in which the fuse element is embedded, making up a fuse which is economical to manufacture, and which fits all types and sizes of plug fuse holders and receptacles at L present on the market.

Still a further object is to design a ashproof plug fuse in which the insulating shot or material is sealed in, thus eliminating any possibility of moisture entering the fuse body or insulation material, and also preventing the escape of sparks or tire when the fuse is blown.

With the above and other Aobjects in view, the present invention consists in the combination and Varrangement of parts, hereinafter more fully described, illustrated in the accompanying drawing, and more particularly pointed. out in the appending claims, it being understood that changes may lbe made in the form, size, proportion, and minor details of construction, without departing from the spirit, or sacrificing any of the advantages of the invention.

ln the drawing:

Fig. l is a side elevational view of my new fiashproof plug fuse.

Fig. 2 is a top plan view thereof.

`- Fig. 3 is `a vertical, transverse sectional view.

Fig. 4 is a perspective view of the fuse element. Fig. 5 is a vertical sectional view of a buss glass tube fuse.

Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 5.

Referring now more specifically to Figs. 1-4 inclusive of the drawing, wherein I have shown a plug fuse P of conventional size and shape. This comprises a plug body 8 shaped as clearly shown in Figs. l, 2 and 3 of the drawing, and this can be formed of glass, porcelain, or any other suitable material. The upper end of the plug is enlarged `as at 9, and the end wall 10 is closed Zzlll Patented Sept. 16, 1958 2 and of reduced thickness as at 11 so that the fuse element may be visible therethrough.

The lower end of the plug 1s shouldered as at 12 to form a cylindrical section of reduced diameter, and a threaded shell or thimble 14 is mounted on said shoulrock wool, vor any other suitable reproof material may be utilized.

A preferably plastic close fitting washer W is inserted in the body 8 at the point shown and is sealed by means of a liquid plasticizer (not shown), to prevent moisture, gas, etc., entering the material M and also preventing escape of sparks when the fuse blows.

The section 15 of fuse element F is disposed relatively close to the inner face of tbe upper end of the receptacle body and is generally covered by said insulated material, `and the legs 16 and 17 project downwardly from section 15 and are embedded in the porcelain 18 which forms a closure for the lower open end of the plug body, the one leg 16 being bent over the lower open end of the body, and thence upwardly between the thimble and the body to form a contact with the thimble or shell. The opposite lleg 17 of said fuse element leads downwardly and is connected to the centrally disposed contact 19 as usual.

The upper end of the fuse or fuse element can be painted or colored with a distinctive color to indicate the fuse amperage or capacity making it unnecessary to read the figures as is presently necessary. For example, the color green could indicate a plug of l5 amperes. The color blue could indicate a plug of 20 amperes. The color yellow could indicate a plug of amperes, and the color red could indicate a plug of amperes, and so on, so that in a relatively short time the public would be referring to plug fuses by color instead of specifying the amperage, and this would be extremely convenient and advantageous inasmuch as the plugs are frequently replaced in dark areas and places where it is difficult to read the printed indicia on the plugs.

On short circuit or overload of the plug fuse the re duced fuse section 15 will blow, but no flame or spark can contact combustible material as the flash or spark is sealed in and smothered in the fireproof material.

In Figs. 5 and 6 of the drawing I have shown a tubularfuse B with a glass tube body 20 having metallic end caps 21 forming a closure for the open ends thereof. The fuse element 22. extends from end to end of the tube and is connected to the caps, said element having a reduced section 23 as usual. In practice the tube 20 is filled with Ian insulating material M which surrounds the fuse element, and it will be obvious that inasmuch as the lireproof material is sealed in any flash will be smothered by said material thus eliminatinfy any possibility of fire or fire hazard. The flashproof material is of a granular nature so any gas formed by the blowing is readily absorbed and no abnormal pressures are built up within the plug body.

From the foregoing description it will .be obvious that I have perfected la very simple, practical and substantial flashproof plug fuse for use in electrical current circuits of all kinds.

What I claim is:

l. An electrical fuse plug comprising a body member formed of insulating material and having a chamber therein closed at one end by a transparent wall; a fuse element located in said chamber and having a portion of its length in 'face to face engagement with said transparent wall so as to be visible therethrough, the ends of said fuse element leading out of said chamber for connection to electrically conductive parts; an insulating member closing the other end of said chamber and having openings accommodating and closely fitting the ends of said fuse element so as to seal said chamber; and a quantity of granulated insulating material filling rsaid chamber and surrounding said fuse element except for said portion in face to face engagement with said transparent Wall, said insulating material being in engagement with the face of said portion of said fuse element which is opposed to the face :of the latter which is in engagement with said transparent Wall.

2. The construction set forth in claim l wherein said portion of said fuse element is colored to indicate a selected capacity.

3. The construction set forth in claim l, in which the insulating material is formed of rock Wool shot sealed in said chamber.

References Cited in the tile of this patent UNITED STATES PATENTS Re. 19,097 Ringwald Feb. 27, 1934 1,167,964 Young Jan. 11, 1916 1,215,999 Schweitzer Feb. 13,V 1917 1,265,223 Marcus May 7, 1918 1,444,637 Nutt Feb. 6, 1,923 1,798,169 Riesman Mar. 3l, 1931 2,073,150 Ludwig Mar. 9, 1937 FOREIGN PATENTS 10,433 Denmark Ian. l0,

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