US2246841A

US2246841A - Refill fuse plug

Info

Publication number: US2246841A
Application number: US231240A
Authority: US
Inventors: Cree John; Corlett Frank
Original assignee: EARLE T BRADFIELD
Current assignee: EARLE T BRADFIELD
Priority date: 1938-09-22
Filing date: 1938-09-22
Publication date: 1941-06-24
Anticipated expiration: 1958-06-24

Description

June 24, 1941.

J. CREE ET AL.

REFILL FUSE PLUG Filed Sept. 22, 1938 GOGGOOG- InUEnt. Errr E J. CREE E DRL-ETT Patented June 24, 1941 REFILL FUSE PLUG John Cree, Hamilton, Ontario, and Frank Corlett,

Crowland, Ontario, Canada, assignors of onethird to Earle T. Bradlield, Hamilton, Ontario,

Canada Application September 22, 1938, Serial No. 231,240

6 Claims.

A still further object is to provide a lock for n the metallic screw shell of the plug so that the latter will not become disengaged from the screw of the insulating body of the plug during the unscrewing of the plug from the metallic screw shell .I

of the fuse block or holder.

With the above and other objects in view which will hereinafter appear as the specification proceeds, our invention consists in its preferred embodiment, of the construction and arrangement all a-s hereinafter more particularly described and illustrated in the accompanying drawing in which- Fig. 1 represents a vertical section through a fuse holder of the screw shell type showing our refill fuse plug screwed thereinto.

Fig. 2 is a side view of our plug taken at right angles to Fig. 1.

Fig. 3 is a vertical section of our plug taken on the line 3-3 (Fig. l), the plug being removed from the fuse holder.

Fig. 4 is a vertical section taken on the line 4 4 (Fig. 2).

Fig. 5 is an inverted plan view of our plug.

Figs. 6 and 7 are respectively side and inverted plan views of the insulating body of the plug.

Figs. 8, 9, and 10 are respectively side, plan and inverted plan views of the capsule inserted into the body of the plug and supporting the fuse element, and

Fig. 11 is a plan View of the fuse element.

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

Our refill fuse plug comprises an exterorly screw threaded cylindrical 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 fuse holder) at its closed end which is of reduced thickness to constitute a window 3 for the inspection of the fuse element. 'Ihe other end of the cylindrical body is open and its lip is provided with a notch 4.

The capsule 5 of insulating material such as porcelain is generally cylindrical in shape and has a circumferential flange 6 therearound intermediately of its length with a lug I formed on the upper face of such flange and adapted to be received into the notch 4 when the capsule is inserted into the interior of the body I with the iiange 6 resting on the lip thereof. The upper part 8 of the capsule wall has a flat external groove 9 at one side registering at its lower end with a slot I0 extending through the flange 6, and at the other side a vertical slot II extending down from the upper end of the upper part of the capsule to the vicinity of the ange.

The lower part I2 of the capsule has a flat face I3 at one side bevelled off at its free end and a central electrical contact I4 extends axially through the lower end of the lower part of the capsule and is riveted to the offset lower end I5 of a conducting post I6 which extends up into the slot I I and supports one end of the fuse element I 'l which is forked and straddles a set screw I3 in the upper extremity of the post I6. The fuse element II extends from the post I6 diarnetrically across the upper end of the capsule, through a notch I9 and down in the groove 9, through the slot It in the flange 6, its other end 20 being turned over outwardly to abut the lower face of the flange 6.

The metallic screw shell 2l having an inturned flange 22 at its outer end dening a central circular opening to receive the lower part of the capsule is threaded onto the body I until its flange 22 abuts the flange of the capsule and makes electrical contact with the end 20 of the fuse element I'I, a slight protuberance 23 being formed on the upper face of the flange 22 to make better contact between flange 22 and fuse element end 20.

In order to prevent the metallic screw shell 2l from unscrewing itself from the body I when the plug is unsorew`ed from the metallic screw shell 24 of the fuse block or holder 25, a lock plate 26 adapted to lie on the flange 22 of the screw shell 2I and pivoted at one end thereto has its inner edge straight abutting the flat face I3 of the lower part of the capsule and its outer edge arcuate `so as to register with the peripheral edge of the screw shell 2|. So long as the screw shell 2I is disposed in the screw shell 24 of the fuse block or holder 25, the latter shell will retain the lock plate 26 in engagement with the flat face I3 on the lower part of the capsule and consequently the screw shell 2| will be prevented from turning relatively to the body I. However, upon the plug being removed from the fuse block or holder, the lock plate will be ineffective to hold the screw shell 2 I in position and it may be unscrewed from the body I, the capsule 5 then being removed and the blown fuse replaced by a new one.

In replacing the fuse element it is only necessary to attach the forked end of the new fuse element to the post by the set screw I8, then bend the fuse element diametrically across the top of the capsule into the notch I9 and down into the groove 9 pushing the free end 20 through the against the lower face of the capsule flange 6 wherein it contacts the flange 22 of the screw shell 2| when the capsule has been inserted into the body I and the screw shell 2| has been threaded thereover. The lock plate 26 is then swung inwardly until its straight inner edge abuts the flat face I3 on the lower part of the capsule when the plug is ready for insertion into the fuse block or holder.

The bevel on the flat face I3 on the lower part I2 of the capsule 5 facilitates the bending over of the end 20 of the fuse element II by permitting the insertion of a finger nail or thin instrument between such flat surface I3 and the inner face ofthe Yend 20 of the'fuse element.

What I claim as my invention is:

1. A refill fuse plug comprising an externally threaded hollow body of insulating material open at one end, a hollow fuse element carrying capsule of insulating material open at one end and having a peripheral flange extending therearound intermediatelyV of its length with a `fuse element receiving slot therethrough in proximity to the outer wall of the capsule, the open ended portion ofthe capsule being inserted into the body with the flange abutting the open end thereof, a contact post extending longitudinally in the interior of the capsule, a central contact extending through the outer end of the capsule and secured to one end of the contact post, a continuous integral fuse element detachably secured at oneend to the other end of the contact post and extending diametrically across the open end of the capsule and downwardly along its outer wall with the other end of such continuous integral fuse element protruding through the'slot in 'the flange and bent outwardly against the lower surface of such flange, a screw threaded shell of conducting material with an inwardly turned flange dening a central opening receiving the outer portion of the capsule, said shell being screwed `onto the -screw threaded body with its flange in abutment with'the flange on the capsule and such screw threaded shell flange making electrical contact with but mechanically unsecured to the outwardly bent end of the fuse element lying against the flange of the capsule, and means for locking the screw threaded shell against rotation relatively to the body only when the plug is being unscrewed 'from `the screw threaded shell of a fuse block or holder.

2. A refill fuse plug `corruslrising an externally threaded vhollow body of insulating material open at-'one end, a hollow fuse element carrying capsule vof insulating material open at one end and having aperipheral ilange extending therearound intermediately of its Alength with a 'fuse element receiving slot therethrough ,in proximity to the outer wall of the capsule, the open ended pontion of the capsule being inserted into the body with the flange abutting the open end thereof, a contact'post extending longitudinally inthe interior of the capsule, a central contact extending through the outer end of Ythe capsule and secured to one end of the contact post, a continuous integral fuse element detachably secured at one-end to the other end of the contact post and ext-ending diametrcally across the open lend of Y the capsule and downwardly along its outer wall with the other end of such continuous integral 'fuse element protruding through the :slot inthe flange and bent outwardly against the lower surslot I0 in the flange and bending it outwardly face of such flange, a Screw threaded shell of conducting malterial with an inwardly turned flange defining a central opening receiving the outer portion of the capsule, said shell being screwed onto the screw threaded body with its llange in abutment with fthe flange on the capsule and such screw threaded shell flan-ge making electrical contact with but mechanically une secured to the outwardly bent end of the fuse elementlying against the ilange of the capsule, a flat side on the outer portion of the capsule, and a, swingable locking plalte mounted on the flange of the screw threaded shell and engageable with said at side of the outer portion of the capsule for locking the screw threaded shell against rotation relatively to the body whenthe plug is being unscrewed Vfrom the screw threaded shell of a fuse block or holder.

3. In a refill fuse plug, in combination, anexternally threaded hollow body of insulating material open at one end, a fuse element carrying capsule of insulating material inserted into such body with one end protruding therefrom, a screw threaded shell screwed onto the body for holding the capsule therein, and lmeans for locking 'the screw threaded shell against rotation relatively to the body-only when the plug is being unscrewed from the screw'threaded shell of a, fuse block or holder.

4. In a refill fuse plug, in combination, an externally threaded hollow body of insulating material open `at one end, a fuse element carrying capsule of insulating material inserted into such body with one end protruding therefrom, a screw threaded-shell screwed onto the body'for holding the capsule therein, a flat side on the protruding end of the capsule, and aswingable locking plate on the screw threaded shell engageable with lthe flat side of-the protruding end of the capsule for lockingthe screw threaded shell against rotation relatively to the-body when the plugis being unscrewed from the screw threaded shell of a fuse block or holder.

5. rThe invention claimed in claim 4 wherein the'screwthreaded shell has an inwardly turned flange defining a central opening through which the protruding end of the capsule extends, and such swingable locking plate is mounted on such flange.

`6. The combination with the screw threaded shell fof a fuse block or holder, of a refill fuse comprising an externally threaded body of insulating-material open `at one end, a fuse element `carrying capsule of insulating material inserted into such body with one end protruding therefrom, a -screw threaded lshell screwed onto the 'body for holding `the'capsule therein, said screw threaded shell having an inturned flange defining a central opening receiving the protruding end of the capsule, a flat side on the protruding end of the capsule, a swingable locking plate on the flange of the `screw threaded shell having a straight inner edge engageable `with the flat side on the protruding Vend of the capsule, and a curved `outer edge conforming with the peripheral curvature of the shell whereby the locking plate is-heldin engagement lwith the flat side of the protruding end of the capsule lwhen the plug is located in the screw threaded shell of the fuse block `or holder.

JOHN CREE. FRANK' CORLE'IT.