US2109901A - Renewable fuse plug - Google Patents

Description

March 1, 1938. s. DERDZINSKI 2,109,901

RENEWABLE FUSE PLUG Filed May 10, 1935 IZ'g- Patented Mar. 1, 1938 UNITED STATES PATENT OFFICE 1Claim.

My invention refers to renewable fuse plugs, and it has for its primary object to provide a removable eiement for such plugs capable of being readily slipped into place for renewal by those 5 unskilled in the art, the same comprising a onepiece ductile element, having spade ends connected by a narrow looped strip, to thus permit ready adjustment into contact clips, and to also permit expansion and contraction between the contact spade ends, which expansion is necessary in a practical device, dueto thermal changes.

Obviously the invention is particularly designed to permit ready renewal of old plugs, whereby the cost of entire new structures is eliminated, which is true under existing normal conditions after a plug fuse has burned out. In other words, it is not necessary to even remove the fuse plug from the fuse box, but upon observation of a blowout, a new element is readily adjusted into position after the closure cap of the plug is removed.

With the above and other minor objects in view, the invention consists in certain peculiarities in construction andarrang ement of parts, as will be hereinafter more particularly set forth with reference to the accompanying drawing:

Figure 1 represents asectional elevation of the plug embodying the features of my invention, the view being upon a magnified scale, the section line being indicated by line l-l of Figure 2.

Figure 2 is a plan view of the plug.

Figure 3 is a detailed sectional elevation of one of the terminals showing the coupling jaw and element therein, the element being in section as indicated by line 3-3 of Figure 1.

36 Figure 4 is a face view of the fuse element.

Referring by characters to the drawing, A represents a standard screw plug having a removable apertured cap B and a mica closure disc 0. The plug is provided with the usual metallic ter- 40 minals l andi, their upper ends I being folded upon themselves to form spring jaws adapted to receive a one-piece element or fuse strip, which strip comprises a pair of spade ends 4-4 connected by a narrow strip 5, which strip portion is ductile and intermediately bowed to form a loop 5. By this construction of fuse elements, it will be observed that the spade ends can be readily inserted into the contact jaws 33, whereby a positive and ample contact is effected 5 between the terminals l and 2. Furthermore, due to the fact that the strip is ductile, the spade element can be adjusted longitudinally, whereby perfect contact is effected, and thereafter the narrow strip 5 will assume a loop, as shown, to permit ready expansion and contraction, and also to provide the desired length of fuse element.

From the foregoing description, it will be observed that when the fuse strip blows out, across the narrow strip portion, this blow-out can be readily observed by an inspection of the plug, and thereafter to renew the entire plug apparatus the operator will simply remove the cap and mica disc, whereby access is had to the hollow shell portion into which -is nested the jaw elements. A new strip is then inserted, and the broken line is immediately renewed at a comparatively nominal expense.

While I have shown and specifically described a standard fuse plug to illustrate my invention, it is obvious that the structural features may be varied within the scope of the claim.

I claim:

In a renewable fuse plug, a body of insulation, 3 a metallic shell on the outer face of said body, a pair of flat conductor strips arranged in spaced parallel relation in said body, the inner end of one strip being electrically connected to the shell, the inner end of the other strip being extended through the inner end of the body to form a central contact, the outer ends of both of said strips being bifurcated forming legs, said legs being twisted at right-angles to the body portions of the strips and back upon themselves in facing 40 relation-to form spring terminals, and a fuse link detachably fitted between said facing bent back spring terminals.

STANLEY DERDZINSKI.

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