US2652466A - Combined fuse and indicator - Google Patents

Description

p 15, 1953 H. H. MOHRING 2,652,466

COMBINED FUSE AND INDICATOR Filed Feb. 29, 1952 m INVENTOR HERMAN H. Momzme Patented Sept. 15, 1953 U NIT ED STATE S PATENT OFFICE 2,652,466, COMBINED; FUSE AND INDICATOR Herman Hi Mohring, Omaha, Ncbr.

Application February 29, 1952, SerialNo. 274,133"

2 Claims. 1

This invention relates toan improved fuse plug assembly of the type which incorporates a lamp for indicating the condition of the fuse.

It is among the objects of the invention to provide an improved fuse plug assembly including a plug body, a replaceable fuse mounted in the body, and a glow lamp mounted in the body to be energized only when the fuse is absent or defective; which will fit into a socket provided for a conventional plug type fuse; which provides a replaceable fuse of less expensive construction than the usual plug type fuse and one which is easier'to replace; which is entirely safe and fireproof and which is simple and durable in construction, economical to manufacture, andpositive and effective in operation.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction C with the accompanying drawing wherein:

Figure 1' is a top plan view of a fuse plug assembly illustrative of the invention;

Figure 2 is across sectional view on the line 2-2 of Figure 1;

Figure 3 is a cross sectional View on the line 3-3 of Figure 2;

Figure 4 is a cross sectional view on the, line 4-4 of Figure 2; and

Figure 5 is a cross sectional view similar to Figure 2, but showing the parts in a different relative position from that illustrated in Figure 2.

With continued reference, to the drawing, the fuse assembly comprises a plug body It of electrically insulative material and of cylindrical shape having a bore or recess ll therein opening, through one end of thebody, the other end of the body being closed by an end wall I2" of partly conical shape. An outwardly projecting annular lateral flange I3 is provided around the open end of the body and the outer cylindrical'surface of the body between the flange l3, and the end wall I2 is provided with a screw thread formation M of substantially semicircular cross sectional shape. Athin walled shell I5 of cylindrical shape and of suitable electrically conductive sheet material, such as sheet brass, closely surrounds the body Ill between the flange [3' and the end wall It and is provided'with a screw thread formation lfireceiving the screw thread formation M on the shell and adapted to thread into a fuse plug receptacle of known construction.

A center contact lI-of electrically conductive material-extends through theend wall 2 of the body centrally ofthe end wall and has a flat head portion on its outer end overlying the ad'- jacen-tend portion: or! the end wall I2 of the:

body.

A first strip 18- of electrically conductive resilient material is connected at one end to the shell l5 at the end of the latter adjacent theconductive resilient material issecured at one end to the center contact H at the end of the latter within the body and extends along the side of the recess IT opposite the strip It and longitudinally of the body and ina direction fromthe end wall 12 towardthe flange 13 of the body.

As is particularly illustrated in Figure 3, the portion-of the recess ll receiving thestrips l8 and I9 is of elongated, rectangular cross sectionalshape and thestrips lfl-and- |9- are disposedalongthe opposed narrowersides of this portion of the recess. The recess includes a lateral extension of semicircular cross sectional shape extending from one of the wider sides of the portion ofrectangular cross sectional'shape for a purpose; to be presently disclosed.

'A- cover 20- of suitable material, such as thin sheet metal, is disposed on the open endof the body [0' and has acylindrical flange portion 2! closely surrounding the flange I3 of the body and an end wall'portion' 22' which overlies the open end of the body H)" in covering relationship to the open end'of the semi-circularextension of the recess Il' inthe body. This cover has an aperture 23 of elongated; rectangular shape registering with the rectangular shaped portion oi the recess II and a small hole 24 opening into the semi-circular extension of the recess II.

A glow lamp 25 is mounted in the extension of the recess I l and extends at its end remote from its base through the aperture 24 in the cover 20; so that the lamp is clearly visible from the exterior of the flanged end of the housing.

A conductor Isis connected at one end to the shell ['5 and atits-other endto the lamp 25 and holdsthe. lamp in positionprojecting through the aperture in the cover, and an electrical resistance element 29" of extremely high resistance isconnected at one end to the other side of the lamp 25 by aconductor 30' and connected at its other end to the strip It by a conductor 31.

The glow lamp 25 1s preferably agasflll'edlamp; a lamp filledwith neon gas being preferred, having spaced apart-electrodes therein; one of which is connected to the conductor 28 and the other to the conductor 30 whereby the lamp is caused to glow when supplied with electrical energy at suflicient voltage.

A plug 32 of elongated, rectangular cross sectional shape has a semi-circularly rounded end 33. Its other end is recessed to provide a groove 34 extending between the narrower sides thereof and a partly cylindrical recess 35 extending inwardly of the inner side of the groove 34 between the narrower sides of the plug. The plug is tapered in width from its rounded end to its recessed end and the portion of the recess ll of rectangular cross sectional shape is correspondingly tapered from its open end toward the closed end of the body, so that the plug 32 will fit tightly into the corresponding portion of the recess.

The plug 32 is provided with shallow grooves extending one along each of the narrower sides thereof from the recessed end of the plug to a location intermediate the length of the plug and terminating in inwardly extending notches, and a strip 35' of fuse material has its end portions offset and inserted in the notches in the narrower sides of the plug. This strip extends along the shallow grooves in the narrower sides of the plug and across the recessed end of the plug within the recess 34 and is of substantially U- shaped form, as is particularly illustrated in Figure 2. The bight portion of the fuse strip extending across the secured end of the fuse plug 32 is notched intermediate its length in a manner well known to the art to provide in this strip a portion of predetermined electrical resistance which will burn out if the fuse is subjected to a current overload of a predetermined value.

The plug 32 is insertable through the aperture 23 in the cover 20 into the rectangular portion of the recess ii and between the strips 58 and [9, so as to bring the portions of the fuse strip 36 extending along the narrower sides of the plug into firm, electrically conductive contact with the strips i8 and I9 as illustrated in Figure 3.

The cover 20 is provided at respectively opposite sides of the aperture 23 in the cover and substantially midway the length of the longer sides of this aperture with downwardly or inwardly extending apertured cars 38 and 39 received in grooves provided in the adjacent end of body it and a U-shaped bail 49, formed of suitable wire, has laterally outwardly oifset end portions pivotally received one in each of the ears 3B and 39, so that the bail extends over the rounded end portion of the plug 32. The plug 32 is provided at the mid-length location of the cylindrically rounded end surface thereof with a notch ll which receives the bight portion of the bail 60 when the plug is fully inserted into the body H] to firmly secure the fuse plug in operative position in the body with the fuse strip 35 in electrically conductive engagement with the contact strip i8 and [9.

As long as the plug is properly positioned in the body l and the fuse strip 36 is intact, the electric current will flow through the fuse strip and the lamp 25 will not glow because the resistance unit 29 will force so much of the current to flow through the fuse strip that insufficient voltage will be impressed on the lamp 25 to illuminate the lamp. However, if the fuse strip is ruptured, then the entire voltage will be impressed on the lamp 25 causing the lamp to glow and indicate that the fuse has blown. The lamp will also glow if the circuit is completed with the plug 32 removed, thereby enabling an electrician to determine the fuse to which a articular circuit is connected in a wiring system.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is:

1. In a fuse plug, an insulated body having a receptacle entering end and another end, said body being provided with a central recess opening through said other end of the body, said central recess being elongated in the direction of the receptacle entering end of the body and termimating in longitudinally spaced relation thereto, a center external contact on said entering end of the body having a portion extending through said entering end into said recess, conductive strips extending longitudinally along opposite sides of said recess, one of said strips being connected at one end to said portion of the center contact and having a free end, a conductive shell mounted around the exterior of said body, the other of said conductive strips having an end connected to said shell and another end unconnected with said center contact, said recess having a lateral extension at one side thereof and located between said conductive strips, said extension opening into said recess, a glow lamp supported in said extension, said glow lamp having one side thereof connected to said shell and another side connected to said other conductive strip, and a removable plug fitting said recess and disposed therein, said plug having a fuse element including side portions extending along opposite sides of said plug in engagement with said conductive strips and a bight portion extending between and connected to said side portions, the side of said plug exposed in the recess extension serving as a wall bounding the open side of the recess extension.

2. In a fuse plug, an insulated body having a receptacle entering end and another end, said body being provided with a central recess opening through said other end of the body, said central recess being elongated in the direction of the receptacle entering end of the body and terminating in longitudinally spaced relation thereto, a center external contact on said entering end of the body having a portion extending through said entering end into said recess, conductive strips extending longitudinally along opposite sides of said recess, one of said strips being connected at one end to said portion of the center contact and having a free end, a conductive shell mounted around the exterior of said body, the other of said conductive strips having an end connected to said shell and another end unconnected with said center contact, said recess having a lateral extension at one side thereof and located between said conductive strips, said extension opening into said recess, a glow lamp supported in said extension, said glow lamp having one side thereof connected to said shell and another side connected to said other conductive strip, and a removable plug fitting said recess and disposed therein, said plug having a fuse element including side portions extending along opposite sides of said plug in engagement with said conductive strips and a bight portion extending between and connected to said side portions, the side of said plug exposed in the 5 recess extension serving as a wall bounding the open side of the recess extension, a cover on said other end of said body, said cover having an opening registering with the open end of said recess and having a portion closing the open end 1 of the recess extension, and means mounting said References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 0 2,266,841 Altschule Dec. 23, 1941 2,416,494 Peterson Feb. 25, 1947

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