US2234024A - Refill fuse plug - Google Patents

Description

March 4, 1941. J, CREE ETAL 2,234,024

REFILL FUSE PLUG Filed Ag. 1o, 1939 ZOMV 55.1. |:1f-E- 36 35 1"113635 FMI-r. El. 29

|4- InUEnLuI'S J. CREE: Il. H WRME Patented Mar. 4, 1941 PATENT OFFICE REFILL FUSE PLUG John Cree and David Anthony Worme, Hamilton Ontario, Canada Application August 10, 1939, Serial No. 289,442

7 Claims.

Our invention relates to improvements in rell fuse plugs and an object of the invention is to devise a plug adapted to contain a plurality of separate fuse elements wherein any selected fuse element of the plurality may be thrown into circuit without removing the plug from the socket or holder when one of the fuse elements which has previously been in circuit is fused by an overload.

A further object is to devise a rell fuse plug in which the plurality of fuse elements may be inserted and removed from the plug as a unit instead of separately.

A still further object is to provide an im- F proved fuse element of bi-metallic construction particularly adapted for use with our plug wherein the ends are constructedv of a metal insusceptible to fusing under ordinary overloads, whereas the body is composed of the orthodox fuse metal capable of fusing upon being subjected to current greater than for which it is designed.

With the above and other objects in View w which will hereinafter appear as our specication proceeds, our invention consists, in its preferred construction, of the construction and are rangement all as hereinafter more particularly described and illustrated in the accompanying drawing in which:

Fig. 1 represents a vertical section through a fuse holder or socket of the screw shell type showing our refill fuse plug (in elevation) screwed thereinto.

Fig. 2 is a vertical section of our plug taken on the line 2-2 (Fig. 4)

Fig. 3 is a vertical section thereof taken on the line 3-3 (Fig. 4), the capsule being shown in elevation.

Fig. 4 is a top plan View of our plug.

Fig. 5 is a side view of the insulating body of our plug.

Fig. 6 isV an inverted plan view thereof.

Fig. 'l is a top plan View of the capsule showing the plurality of fuse elements mounted thereon.

Fig. 8 is an inverted plan View thereof partly in section.

Fig. 9 is an elevational detail of a manually operable rotatable contact for throwing any sen lecterl fuse element into circuit.

Fig. 10 is a detail in plan showing the means for mounting the fuse elements whereby they may be inserted into and removed from the capsule as a unit, and

Figs. 1l and 12 are respectively plan and edge views of one of our bi-metallic fuse elements.

Like characters of reference indicate corresponding parts in the different views of the drawing.

Our rell fuse plug comprises an exteriorly threaded cylindrical insulating body I preferably composed of heat resisting glass with a peripheral flange 2 (by means of which the plug is screwed into and unscrewed from the screw shell 3 of the holder 4) in the vicinity of its closed end 5. The other end of the body I is open and provided with a plurality of spaced apart notches 6.

The capsule 1 of insulating material such as porcelain is generally cylindrical in shape and hollow and has a circumferential flange 8 therearound intermediately of its length with a plurality of spaced apart` lugs 9 on the upper face of such flange adapted to be inserted into the notches 6 when the capsule 'I is inserted into the body I with its flange 8 resting on the lip of the open end of the body. The interior of the capsule has a central contact receiving bore I0 of reduced diameter at its lower end and the upper lip of the capsule is provided with diametrical extending grooves II. The wall of the upper part I2 of the capsule is` provided with a plurality of vertical spaced apart fuse element receiving grooves I3 with their inner surfaces concave in longitudinal section, said grooves being located on the capsule between the lugs 9 on its flange 8.

The plurality of fuse elements each comprises a strip of fuse metal I4 forming the body of the fuse element ond end strips I5 of normally non-fusible metal such as copper, sweated or otherwise securedto the strip I4. The upper end strips I5 are hooked around the periphery of an insulating disc I B and through spaced apart slots Il in the Vicinity of its periphery located in radial grooves I8 in the top of the disc, the lower end strips I5 being hooked about the flange 8 of the capsule 'I also in spaced relation so that the fuse element portions Ill lie in the vertical grooves I3 in the capsule wall leaving air spaces between the portions I4 and the inner surfaces of such grooves.

The insulating disc I having a central orifice I9 therethrough is detachably mounted on the upper end of the capsule 'I with pimples 2t) inserted into the diametrical grooves il for preventing it rotating relatively to the capsule, and is held on such capsule by the lower ends I5 of fuse elements being hooked over the flange 8 as above referred to.

A metallic screw shell 2| having an inturned flange 22 at its outer end defining a central circular opening to receive the lower part 23 of the capsule is threaded onto the body I until its flange 22 abuts the flange 8 of the capsule and makes electrical contact with the lower ends I5 of the fuse elements. An upwardly extending resilient lug 24 formed on the upper end of the screw shell 2I is adapted to be inserted into an indentation 25 in the body I for positively locking the screw shell 2| to the body against relative rotation when the plug is screwed into the holder 4.

When the plug is disconnected from the holder the lug 24 does not lock the screw shell 2| to the body as the lug is not then located in the indentation 25 having, due to its resiliency, di=- engaged itself therefrom.

Prior to the application of the screw shell 2l to the body I a spindle 26 carrying the central contact 21 at its lower end is inserted into the capsule with the contact 21 extending through the bore Il) and protruding therefrom. The contact 21 is provided with an air vent 21d in the form of a vertical slit in its periphery. The upper end of the spindle extends freely through an orifice 28 in the upper end 5 of the body I and has a squared extremity 29 protruding exteriorly thereof to which is cemented or otherwise secured the actuating knob 3D.

A boss 3| is provided on the spindle 2B intermediately of its length from which extends a radial finger contact 32 adapted to make contact with the respective upper ends I5 of the fuse elements. A leaf spring 33 having a central orifice 34 is provided on the spindle 2E between the boss 3l and the upper end 5 of the body I.

Radial fuse indicating notches 35 are located on the flange 2 of the body I in register with the grooves I3 in the capsule and therefore with the fuse elements therein, and similar notches or serrations 36 may be provided on the knob 30.

When the plug is once screwed into the holder it is unnecessary to remove it until all the fuses are burnt out. The finger contact 32 is initially set by rotating the spindle by means of the knob 30 so that such nger contacts with the upper end I5 of any one fuse element. When such fuse element due to overload is burnt out, it is only necessary to pull out the knob a limited extent against the action of the spring 33 and rotate the spindle until the linger contact enters the next radial slot I8 wherein the finger makes Contact with the upper end I5 of the next fuse element.

The provision of the vent 21a and the radial grooves II as well as the concave surfaces in the grooves I3 enables the gases resulting from the fusing of the fuse elements to be adequately vented.

When all the fuse elements attached to the disc have been burnt out the plug may be removed and the screw shell 2| unscrewed from the body. The capsule may then be removed, leaving the spindle 26 in position, and the unfused portions of the fuse elements may then be detached from the capsule flange and disc and replaced by a fresh supply of fuse elements when the plug may be then reassembled. Alternatively, if desired, the refill instead of consisting of new fuse elements alone may consist of a new disc as well with the new fuse elements already assembled thereon.

What I claim as my invention is:

1. A fuse plug comprising an externally threaded hollow body of insulating material open at one end, a hollow fuse element carrying capsule of insulating material having a peripheral outwardly directed flange extending therearound intermediately of its length, said flange adapted to seat on the lip of the open end of the body, a plurality of independent fuse elements entirely mounted on the side and one end of the exterior of the capsule, a metallic screw shell adapted to be screwed on the threaded body and make electrical contact with the corresponding end of each fuse element located on the side of the exterior of the capsule, and means in the body including operable means disposed exteriorly thereof for selectively making electrical contact with the other ends of the fuse elements on the end of the capsule.

2. The invention claimed in claim 1 wherein a member of insulating material is superimposed On the inner end of the capsule and the ends of the fuse elements adapted to make contact with the contact means in the body are attached to such member, and such contact means in the body is rotatable axially therein and includes an outwardly extending contact adapted to make electrical contact selectively with the respective ends of the fuse elements attached to the member of insulating material.

3. The invention claimed in claim l wherein a disc of insulating material having a plurality of radial grooves in a face thereof with slots in such grooves in the vicinity of its periphery is mounted on the capsule, and the ends of the fuse elements adapted to make contact with the contact means in the body are hooked through the slots and extend into the grooves, said contact means in the body being axially rotatable therein, and an outwardly extending contact on the ccntact means in the body adapted to make electrical contact selectively with the respective ends of the fuse elements extending into the grooves in the disc.

4. The invention claimed in claim 1 wherein a disc of insulating material having a plurality of radial grooves in a face thereof with slots in such grooves in the vicinity of its periphery is mounted on the capsule, and the ends of the fuse elements adapted to make contact with the contact means in the body are hooked through the slots and extend into the grooves, said contact means comprising a longitudinally movable and rotatable metallic spindle extending axially and freely through the body, disc and capsule and including a Contact protruding from the outer end ofthe capsule and an outwardly extending contact located intermediately of the length of the spindle for selectively making electrical contact with the respective ends of the fuse elements extending into the grooves in the disc.

5. The invention claimed in claim 1 wherein a disc of insulating material having a plurality of radial grooves in a face thereof with slots in such grooves in the vicinity of its periphery is mounted on the capsule, and the ends of the fuse elements adapted to make contact with the Contact means in trie body are hooked through the slots and extend into the grooves, said contact means comprising a longitudinally movable and rotatable metallic spindle extending axially and freely through the body, disc and capsule and including a contact protruding from the outer end of the capsule and an outwardly extending contact located intermediately of the length of the spindle for selectively making electrical contact with the respective ends of the fuse elements extending into the grooves in the disc, said spindle protruding exteriorly of the body, and a knob of insulating material on such protruding end.

6. The invention claimed in claim 1 wherein a plurality of spaced apart longitudinal grooves are provided on the exterior of the capsule and the fuse elements are receivable therento, the inner surfaces of such grooves being concave in longitudinal section to space the fuse elements dism posed therein from such inner surfaces.

7. In a fuse plug, a removable capsule of insulatng material having a peripheral flange eX- tending therearound intermedately of its height, a member of insulating material superimposed on the capsule, and a pluralit7 of independent fuse elements attached in spaced relation at their upper ends to the member and extending down the exterior of the capsule, and hook-shaped lower ends on the fuse elements adapted to be hooked over the peripheral edge of the ange.

JOHN CREE.

DAVD ANTHONY WORME.

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