US2119269A

US2119269A - Refill fuse plug

Info

Publication number: US2119269A
Application number: US90404A
Authority: US
Inventors: Cree John; Corlett Frank
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-13
Filing date: 1936-07-13
Publication date: 1938-05-31
Anticipated expiration: 1955-05-31

Description

May 31, 1938. J, CREE ET AL 2,119,269

REFILL FUSE PLUG Filed July l5, 1936 ATTORNEYS Patented May 31, 1938 UNITED STATES PATENT OFFICE REFILL FUSE PLUG Application July 13,

2 Claims.

Our invention relates to improvements in fuse plugs for use in electrical circuits and the primary objective sought is the provision of an inexpensive, durable plug of this character of few parts which may be readily disassembled and the fuse element thereof easily and quickly replaced.

Another object is to provide a plug of the character and for the purpose above'set forth provided with a sight glass protected by a replaceable element against being burnt, and thereby clouded, when the fuse element is burnt or blown out whereby the plug may be kept in a condition in which the interior thereof is visible through said sight glass.

To the accomplishment of the above, and subordinate objects presently appearing, a preferred embodiment of our invention has been illustrated in the accompanying drawing, set forth in detail in the following description, and defined in the claims appended hereto.

In said drawing:-

Figure 1 is a view in end elevation of our improved fuse plug looking at the outer end thereof.

Figure 2 is a view in side elevation.

Figure 3 is a view in longitudinal section taken on the line 3-3 of Figure 2, looking in the direction indicated by the arrows.

Figure 4 is a View in side elevation of the body part of the fuse plug.

Figure 5 is a similar view of a capsule adapted to be tted in the body part.

Figure 6 is a view in end elevation of the inner end of the capsule, and,

Figure 7 is a view in plan of the fuse element.

Referring to the drawing by numerals, the plug of our invention in its illustrated embodiment, comprises a sleeve-like cylindrical body part I, preferably of glass, and including an exteriorly threaded shank part 2, a flanged outer end 3, and a cylindrical bore 4.

The outer end 3 is formed with a raised, thin, central portion 5 providing a sight glass 6 through which the interior of the body part is visible. On its inside the head is formed with an outwardly flaring central socket 'I directly behind the sight glass 6 in which a mica disc 8 is fitted with a press fit for the purpose of protecting the sight glass 6 against becoming smoked and blurred when the fuse element, presently described, is burnt or blown out.

Fitted into the bore 4, from the inner end thereof is a substantially cylindrical sleeve-like capsule 9 having a radial iiange I0 intermediate its ends adapted to fit against the inner end of the shank part 2, a tapered outer end II extending out- 1936, Serial No. 90,404

(Cl. 20G-130) wardly of said flange I0, a flat side I2 extending from the flange I0 toward the inner end of the capsule and terminating at the inner edge of the latter in a squared aperture I3, and a slot I4 extending from the inner end of the capsule 9 to a. point adjacent to ange II) and diametrieally opposed to the recess I3. The purpose of the recess I3 and the slot I4 will presently be explained.

The capsule 9 is formed of glass or other suitable insulating material and is secured in the bore 4 by means of a threaded shell I5 of brass or other conducting material, and having an apertured end I6 tting over the end I I of the capsule 9 and bearing against flange IIB. The shell I5 is threaded onto the shank part 2 and retained` thereon against turning by pressing the edge thereof into a kerf II provided in the shank part 2. The capsule 9 1s locked to the shank part 2 against relative turning movement by means of a squared boss I0 on the shank side of the flange I0, aligned with the flat side I2 and fitting into a correspondingly shaped recess 2 formed in the inner end of the shank part 2.

A contact post I8 is fitted into a counter bore I9 in the capsule 9, said post having a disc-like outer contact part 20 fitting against the outer end of the capsule 9 and being split longitudinally to provide a part 2|, for interlocking engagement with the capsule 9 to anchor the post in the latter, and a fuse carrying part 22 having a squared end 23 extending into said capsule along side the slot I4 in the latter for a purpose presently clear. The interlocking engagement between the post I8 and the capsule 9 is effected by bending the part 2| over against a curved ledge 23 provided at the inner end of said counter bore I9.

The fuse element 24 comprises a strip of flexible conducting material of any suitable character having inwardly extending

slots

25 and 26 in its opposite ends, respectively, and an intermediate portion 2'I of reduced width. The fuse element 24 is secured at one end to the square part 23 of the post I8, bent at right angles to extend across the inside of the capsule 9, through the recess I3, and downwardly along side the flat side I2 of said capsule. The other end of the fuse strip 24 is inserted through a slot 28 in the boss IIJ' and flange I0 and is turned outwardly against the outside of said flange as shown in Figure 3. The first mentioned end of said element 24 is secured to the squared part 23 by means of a screw 28 passing through the slot 2S in said end of the element. The other end of said element 24 is secured to the fiange I0 by means of a squared key block 29 seating in a correspondingly shaped recess 30 formed in the outer side of said flange I0 and boss I0 and to which block said end of the element 24 is secured by means of a screw 3I. The head of the screw 3| engages the shell I5 to establish a circuit through the post I 8, element 24 and said shell I5. The reduced portion 2l of the fuse element 24, as will be understood, provides a weakened portion in said element to be burnt or blown out in the event of an over-load in the circuit. The arrangement of the fuse element 24 is such that the weakened portion 21 is parallel with the sight glass 6 and thereby plainly visible through the latter.

By forcibly unscrewing the shell I5 and forcing the detent therein out of the kerf I'I, the capsule 9 together with the fuse element 24 may be easily and quickly removed from the body part I of the plug and the key block 29 and corresponding end of the element 24 detached from the flange IQ. The screws 28 and 3l may then be removed and the burnt or blown out fuse replaced. The slot I4 in the capsule 9 facilitates the insertion of a screw driver against the screw 28 and the latter in the post and provides for visibility in positioning the slotted end of the fuse element over said screw. The recess i3, flat side I2, and key block 29 provide a simple arrange` ment of parts functioning in conjunction with the bore 4 to securely hold the fuse element 24 in proper position. When the mica disc 8 becomes smoked, or otherwise clouded, it may be readily pried out of the socket l and replaced with a new one.

The foregoing description will, it is believed, suffice to impart a clear understanding of our invention together with the advantages thereof.

It is to be understood that the present disclosure is illustrative of preferred embodiment of our invention, only, and that right is herein reserved to modications in details described falling within the scope of the appended claims.

What we claim iszl. In a fuse plug, a cylindrical sleeve-like body part of insulating material exteriorly threaded,

a cylindrical sleeve-like capsule fitted into said part and including an intermediate radial flange adapted to seat against one end of said part and a flat outer side extending from said flange toward the inner end of the capsule and terminating in a recess in said end of the latter, a cylindrical cup-like shell of conducting material threaded onto said part and iitting over said capsule against said ange to retain the capsule in the body part, a contact post extending into said capsule from one end thereof, and means for detachably securing said other end to said flange comprising a squared key block, said ilange having a correspondingly shaped recess therein receiving said block.

2. In a fuse plug, a cylindrical sleeve-like body part of insulating material exteriorly threaded, a cylindrical sleeve-like capsule fitted into said part .and including an intermediate radial flange adapted to seat against one end of said part, and g a flat outer side extending from said flange to ward the inner end of the capsule and terminat ing in the recess in said end of the latter, said capsule having a longitudinally extending slot therein opposite said recess, a cylindrical cupn like shell of conducting material threaded onto said body part and fitting over said capsule against said flange to retain the capsule in said part, a contact post extending into said capsule along side said slot, a strip-like fuse element having slotted ends and extending from said post across said capsule through the recess therein and along side said at face and through said iiange, a screw passing through the slot in one end of said Velement to secure the latter to the post, the I key block, and a screw passing through. the slot and into said block said flange having a recess therein receiving said block.

JOHN CREE. FRANK CORLETT.