US2766353A - Refillable fuse plug - Google Patents

Description

Oct. 9, 1956 J. I. DURHAM ETAL REFILLABLE FUSE PLUG Filed May 17, 1955 FIG.2

FIG. 3

FIG.6

FIGQS I llllll 5 m t n e v n FIG.8

JOHN A. CRE

JAMES DURHAM United States Patent O REFILLABLE FUSE PLUG James Irvine Durham and John A. Cree, Hamilton, Ontario, Canada Application May 17, 1955, Serial No. 509,019

3 Claims. (Cl. 200-130) This invention relates to improvements in refillable fuse plugs of the type wherein the plug contains a ribbon fuse and is threaded for insertion into an electrical socket, and the object of the invention is to devise a plug which may be very readily taken apart for the replacement of a burned out fuse.

In carrying out the object of the invention we provide a very practical and simple plug arrangement consisting of three quickly separable portions which are normally locked in assembly by a manually releasable pawl-like spring clip carried by an outer threaded metal sleeve to engage a notched face on the fuse carrying portion of the plug, such portion being contained within an insulator cup upon which the metal sleeve is threaded.

Another object of the invention is to releasably secure the ribbon fuse to a contact post contained within the fuse carrying portion and to so form the fuse that its outer end length is clamped between the side face of the insulator cup and the metal sleeve threaded thereunto.

With the foregoing and other objects in view, as shall appear, the invention consists of a refillable fuse plug formed and arranged all as hereinafter more particularly described and illustrated in the accompanying drawing in which:

Figs. 1, 2 and 3 are perspective views of the three separable portions forming the plug.

Fig. 4 is an inverted plan view of the fuse carrying portion shown in Fig. 2.

Fig. is a side view of the assembled fuse plug.

Fig. 6 is a vertical cross-sectional view through the assembled fuse plug.

Fig. 7 is a transverse cross-sectional view through the assembled fuse plug.

Fig. 8 is an inverted plan view of the assembled fuse plug.

Fig. 1 illustrates the fuse containing cup 2 which is generally molded of insulating material, such as glass, and having a clear face 3 in its top through which the fuse may be seen. Threads 4 are forme on the side of the cup together with a groove 5 for receiving the outer end length of a ribbon fuse, as shall be hereinafter explained.

Fig. 2 illustrates the fuse carrying portion 6 which is also formed of insulating material and dimensioned to fit within the cup 2 with its lower end 7 projecting therefrom, the portion having a flange 8 upon which the cup rests. A metal contact post 9 in the form of a strip is contained within a recess 10 in one side of the portion 6 and constitutes an electrical connection between a contact face 11 in the bottom face of the lower end 7 and a fuse anchoring terminal screw 20 threaded into the upper end of the post. The lower or exposed face of the flange is formed with a series of radial serrations or notches 12 for engagement by the assembly locking spring clip, as shall be explained.

Fig. 3 illustrates a metal sleeve 13 having threads 14 formed in its wall, the sleeve being arranged to be threaded into a fuse plug receiving electrical socket. The lower 2,766,353 Patented Oct. 9, 1956 end of the sleeve is formed with an inturned flange 15 which rests against the serrated face of the flange 8 when the plug is assembled, as shown in Fig. 6. A pawllike spring clip 16 is secured at one end to the outer face of the flange 15 and is inturned at the other end to freely project through an orifice 17 in the flange and to engage one of the serrations in the flange 8 when the sleeve is threaded home upon the cup 2.

The serration engaging free end of the clip extends in the opposite direction to the direction in which the sleeve is turned in being threaded home upon the cup, whereby in the final turning and tightening movement the free end of the clip clicks over the serrations in a pawl-like manner, but prevents the sleeve from unthreading from the cup until the end of the clip is manually moved outwardly from serration engagement. To retain the fuse carrying portion 6 against rotation in the cup 2 the inside face of the cup is formed with a chord flat 18 engageable by the edges of the recess 10.

The ribbon fuse is pre-shaped for placement within the fuse plug and comprises a bridge piece 19 adapted to extend across the top of the portion 6, being downturned and pierced at one end for reception of the terminal screw 20 and formed at the other end with a U-shaped outer end length 21 adapted to have its inner leg contained within a groove 22 in the portion 6 and which is opposite to the groove 18 and its outer leg contained within the groove 5 in the outer face of the cup 2, such leg being corrugated in registering configuration with the cup threads 14, and by means of which electrical contact is established when the sleeve 13 is threaded upon the cup.

When assembled and positioned within a socket, current flows through the fuse which forms a bridge between the contact face 11 and the metal sleeve 13, as in standard practice. Should the fuse burn out it is only necessary to remove the plug from the socket, slightly pull the free end of the clip 16 from out of contact with the serration it is engaging and unscrew the sleeve 13 from off the cup 2 to take the plug apart for replacement of a burned out fuse.

From the foregoing description it will be seen that due to the spring clip lock between the sleeve and the portion 6 within the cup that the plug cannot come apart when being unthreaded from a socket, and that by easing the clip outwardly by a slight pull, the plug may be instantly taken apart for fuse replacement.

What we claim as our invention is:

1. In a fuse plug, a cup-like body part of insulating material exteriorly threaded, a fuse carrying member fitted into said part and including a flange serrated upon its exposed face and adapted to seat against the rim of the cup part and a fuse receiving groove extending from the flange to the inner end of said member, a sleeve of conducting material threaded unto said cup part to retain the fuse carrying member within the part and having a lower portion overlying the serrated face of the flange, a manually releasable pawl-like element carried by the sleeve to engage the serrated face of the flange to normally retain the sleeve against unthreading turning from off the cup part, a contact post contained within the fuse carrying member and extending from its exposed face to the vicinity of its inner end, and a fuse extending from the inner end of the contact post to the conducting material sleeve.

2. A fuse plug as defined in claim 1, wherein the fuse is in the form of a ribbon extending across the inner end of the fuse carrying member and down the groove in said member and across the rim of the cup part to be sandwiched between the outer face of said part and the conducting material sleeve carried thereby.

3. A fuse plug as defined in claim 1 wherein the fuse is in the form of a ribbon extending across the inner end of the fuse carrying member and down the side of said member and across the rim of the cup part to be sandwiched between the outer face of said part and the conducting material sleeve carried thereby.

References Cited in the file of this patent UNITED STATES PATENTS 904,832 Bradley Nov. 24, 1908 4 Brown Oct. 3, 1933 Dalcher Feb. 15, 1938 Cree et a1. June 24, 1941 Brus Aug. 15, 1944 Larson May 19, 1953

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