US2276703A

US2276703A - Fuse plug construction

Info

Publication number: US2276703A
Application number: US386403A
Authority: US
Inventors: Schmidt Lambert
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-04-02
Filing date: 1941-04-02
Publication date: 1942-03-17
Anticipated expiration: 1959-03-17

Description

March 17, 1942. L, sg 2,276,703

FUSE PLUG CONSTRUCTION Filed April 2, 1941 :WIWIII INVENT OR.

Patented Mar. 17, 1942 UNITED STATES EATENT OFFICE 7 Claims.

This invention relates to improvements in fuse plug constructions and more particularly to improvements in the manner in which fuse strips are secured in the center terminals of fuse plugs.

An object of the present invention is to provide a fuse plug construction wherein the fuse strip is secured to one of the terminals in an improved manner.

Another object of the invention is to provide a new type of connection between the fuse strip and one of the terminals of a fuse plug.

A further objectv of the invention is to provide a connection between a fuse: strip and one of the terminals of a fuse plug; which connection is of such character as to maintain good electrical contact between the parts. and to simplify the process of manufacture thereof.

A further object of the invention is to provide an. improved attachment, as before described, in which a fuse strip is held in a hollow terminal by means of a resilient spring member.

An additional object of the invention is to provide an arrangement whereby a fuse strip is held in a hollow terminal member by means of a substantially U-shaped spring retaining member.

A further object of the invention is to provide an arrangement as. before described, in which the terminal member has a hollow portion of substantially rectangular or square shape in cross section and in which the substantially U-shaped spring retaining member is made from flat stock.

A still further object of the invention is to provide anarrangement as described in which the terminal has a hollow portion of circular shape in cross section and in which the substantially U-shaped. member has curved leg portions to conform to the general shape of the hollow portion.

Incarrying out the foregoing and other objects of the invention, a. fuse plug is constructed in such fashion as to be. made up of a body portion hollowed out and having-a through aperture in the bottom, thereof. In addition, use is made of a shell part cooperating with the body part and secured thereto by an externally threaded metallic ferrule which servesas one terminal as the plug; one end olithe fuse strip being secured thereto in conventional fashion. The second terminal member used in this fuse plug construction is so shaped asto have a hollow part extending through the aperture in the body and having a flanged part, or disc, underlying the bottom edge or surface of the body. This hollow portion may be of any desired shape in cross section, such as. rectangular, square, round, polyg- 68 onal, hexagonal, or any other suitable shape. For convenience and brevity, two shapes are illustrated in the accompanying drawing, The terminal member, including the hollow portion, can be secured in the aperture in the body either by turning a part of the upper edge thereof over against the upper surface of the hollowed out part of the body or this terminal may be retained in the aperture by a frictional tight fit.

The hollow part is provided to receive one end of the fuse strip (the other end of which is secured to the outer ferrule) and the end within the central terminal is retained in place by a substantially U-shaped metallic spring member inserted into the terminal in such fashion that one leg of the spring bears against the strip within the terminal and the other leg bears against the wall of the terminal. This spring member can have serrated edges or surfaces if desired, to aid in retaining the same in assembly with the strip end and with the terminal.

Other features, objects and advantages of the invention will be apparent by reference to the following detailed description of the accompanying drawing, wherein Fig. 1 is a horizontal section of a part of a fuse plug embodying the invention, such section being taken substantially on the line I| of Fig. 2;

Fig. 2 is a side View partially in vertical section of the same device, taken substantially on the line 22 of Fig. 1;

Fig. 3 is a side elevation of a spring retaining member utilized in the invention;

Fig. 4 is a plan View of a body member plus a strip assembly of a modified form of the invention, and

Fig. 5 is a section taken substantially on the line 5--5 of Fig. 4.

Referring now to the drawing and particularly to Figs. 1 to 3 inclusive, l0 indicates a body for a fuse plug construction, such body being made of some suitable insulating material. The body as shown, has a depending portion II with a flat bottom 12, flange part l3 and an upstanding tubular part M. In conjunction with the base l0, use is made of a shell 15 of glass, or other conventional material, and a metallic ferruleit having a bottom flange IT. This metallic ferrule H3 is formed to provide a thread and preferably the shell l5 has its outer surface threaded so that the ferrule l6 can be screwed onto the shell IE to hold the parts in assembly with the flange ll underlying the flange l3. These parts are of conventional fashion and are shown in the drawing only to illustrate one type of generally known fuse plug construction. It is to be understood that other types of construction can be used in the present invention without departing from the spirit and scope thereof.

The body II) has a through central aperture 25 to receive a hollow part 2| of a terminal member. This hollowed out part 2I has a flared bottom edge portion 22 to which is secured a disc member 24, the edges of which are curled around the flared out part as shown in Fig. 2. In the arrangement illustrated in Figs. 1 and 2, the aperture 20 is of substantially square shape in cross section and consequently the hollow part 2| of the terminal is likewise of square shape in cross section. This hollow part is so dimensioned as to be insertable into the aperture 26) with a very tight frictional fit therein. For this reason the bottom part of the aperture wall is rounded out to facilitate introduction of the terminal into the recess. be sufiicient to retain the terminal in assembly with the base, but if desired, opposite parts 25 of the upper edge portion of the hollow part H can be spread outwardly over the upper surface of the material surrounding the aperture 28. This spreading action can be accomplished by a suitable tool.

A fuse strip 3!] of the usual type has one end thereof retained in the hollow part 2| of the central terminal in such fashion that good electric contact is maintained between the end of the strip and the terminal. For this purpose, use is made of a spring member 35 of substantially U-shape. The spring member like the terminal can be made of any suitable metal, such as copper, brass, spring bronze or any other desired suitable material. Likewise, the spring 35 may have serrations 36 on the surfaces of the leg portions thereof, which serrations are so disposed as to permit ready introduction of the spring into the terminal but as to resist withdrawal of the same therefrom.

The fuse strip 30 of the retaining member 35 can be assembled with the terminal either before or after the terminal has been assembled with the body I0. If desired, the terminal can be placed in a suitable support and the fuse strip and retaining member insertable thereinto either by hand or by proper mechanism. After such insertion has been accomplished, the strip and terminal may be introduced into the aperture 29 and then the terminal forced home into the position shown in Fig. 2. If the parts are so dimensioned as to provide a tight frictional fit, further clinching of the terminal may not be necessary, but as a safeguard against adventitious removal of the terminal, parts 25 thereof can be flared as shown. The spring retaining member 35, however, increases the friction between the hollow part of the terminal and the aperture 20, due to the tendency of the spring 35 to expand, and consequently the friction between the wall of the aperture and the wall of the hollow part of the terminal is accentuated. This arrangement therefore serves admirably to retain a fuse strip in assembly with the central terminal of a fuse plug.

While the assembly shown in Figs. 1 to 3 make use of a terminal having a hollow part of substantially square outline, it is evident that such hollow part may have any other suitable outline. The square outline shown is the preferred form since the fit between the terminal and the body is of such obvious character as to prevent rotation between these parts. Any shape other than In some cases this frictional fit will round likewise will produce the same results.

However, it may be desirable to use a terminal having a hollow part of circular shape in cross section and such an arrangement is shown in Figs. 4 and 5. In these figures the parts are substantially similar to those previously described and only the body member III] and terminal and fuse strip are shown. The body member III) has a depending part III, a flat bottom portion H2, a flange part H3, and a tubular part I I4. This body part likewise has a through aperture I but such aperture is of circular shape in cross section. In conjunction with this body, use can be made of a central terminal member having a hollow part I2I likewise of circular shape in cross section and flared outwardly as at I22. A disc I24 is secured to the hollow part in the manner previously described. Similarly, opposite parts I25 can be flared outwardly to retain the terminal in assembly with the body. A fuse strip I is retained in the terminal by means of a substantially U-shaped spring mem ber I35, which spring member however, has the leg portions thereof rounded slightly as shown at I40 so that these leg portions can conform to the shape of the hollow wall part I20 and cause the fuse strip to likewise assume a roiuided shape with such wall.

As in the case of the Figs. 1 and 2, embodiment of the invention, the terminal and fuse strip can either be preassembled before introcluction into the body of the plug or, if desired, the terminal can first be assembled with the body and then the fuse strip and spring retaining member introduced into the terminal after such attachment. The spring member I may have serrations on the outer surface of the leg parts thereof as in the case of the member 35 if desired, but it is to be understood that in any event, such serrations may be omitted if the same seems to be warranted.

From the foregoing it will be seen that the present invention provides new, simple and efficient arrangements for securing fuse strips to the center electrodes of fuse plugs, which arrangements materially reduce the cost of manufacture without sacrificing any advantages heretofore obtained by the use of solder or other expensive attaching devices. The spring retaining member assures that the fuse strip will be forced into such intimate contact with a part of the terminal as to assure good electrical contact between these parts. The invention can be modified beyond the illustrated embodiments and accordingly, any limitations imposed thereupon are to be only those set forth in the following claims.

What is claimed is:

1. In a fuse plug, a body, a terminal member secured in said body, said terminal member having a hollow portion, a fuse strip having one end inserted into said hollow portion, and a spring retaining member of electrical conducting material inserted into said hollow portion to bear against the wall of the hollow portion and against the end of said strip and force said end into contact with the wall of said hollow portion.

2. In a fuse plug, a body, a terminal member secured in said body, said terminal member having a hollow portion, a fuse strip having one end inserted into said hollow portion, and a substantially U-shaped resilient retaining member inserted into said hollow portion to have one leg bear against the wall of the hollow portion and the other leg to bear against the end of said strip and force it into contact with the wall of said hollow portion.

3. In a fuse plug, a body, a terminal member secured in said body, said terminal member having a hollow portion of substantially square shape in cross section, a fuse strip having one end inserted into said hollow portion, and a resilient retaining member inserted into said hollow portion to bear against the end of said strip and force it into contact with the wall of said hollow portion.

4. In a fuse plug, a body, a terminal secured in said body, said terminal having a hollow por-- tion communicating with the interior of said body, a fuse strip having one end inserted in said hollow portion and a retaining member of substantially U-shape, said retaining member being inserted into said hollow portion and resiliently locking the end of said strip therein.

5. In a fuse plug, a body having a through opening, a terminal member having a hollow portion fitting snugly in said through opening, a fuse strip having one end inserted in said hollow portion, a substantially U-shaped spring member inserted in said hollow portion to retain the end of said strip therein, the upper edge portions of said hollow portion being clinched to said body in opposite relation between the legs of said retaining member to prevent separation of the terminal from the body.

6. In a fuse plug, a body having a through opening of substantially square cross section, a terminal member having a hollow portion fitting snugly in said through opening, a fuse strip having one end inserted in said hollow portion, a substantially U-shaped spring member inserted in said hollow portion to retain the end of said strip therein, the opposite upper edges of said hollow portion between the legs of said retaining member being outturned over the upper edges of the through opening to prevent withdrawal of the terminal from the body.

7. In a fuse plug, a body having a through opening of substantially cross section, a terminal member having a hollow portion fitting snugly in said through opening, a fuse strip having one end inserted in said hollow portion, a substantially U-shaped spring member inserted in said hollow portion to retain the end of said strip therein, the upper edge portions of said hollow portion being clinched to said body in opposite relation between the legs of said retaining member.

LAMBERT SCHMIDT.