US2200496A - Fuse cut-out - Google Patents

Description

May 14, 1940. Q FOX FUSE CUT-OUT Filed Dec. 6, 195':

2 Sheets-Sheet 1 5 ATTUE/YE Y May 14, 1940. I c, ox 2,200,496

FUSE CUT-OUT Filed Dec. 6, 193'? 2 Sheets-Sheet 2 ,4 TTOE/YEY Patented Why 14, 1940 PATENT OFFICE.

FUSE CUT-OUT Charles Adin Fox, St. Louis, Mo., assignor to James R. Kearney Corporation, St. Louis, Mo., a corporation of Missouri Application December 6, 1937, Serial No. 178,329

7 Claims.

This invention relates generally to electrical fuse cut-outs and more specifically to a fuse cutout of the type generally described in the electrical industry as a hang-on switch, the pre- .5 dominant object of the invention being toprovide a device of this type which is of unique and improved construction and is capable of performing its intended function in a highly efficient manner.

l Hang-on switches are so designated because they are clamped or otherwise secured directly to power transmission lines, and ordinarily these switches are employed in association with transformers and other electrical devices so as to prevent passage to such electrical devices of abnormal current. Briefly stated the improved cut out disclosed herein comprises two related parts one of which is clamped or otherwise secured to a power transmission line, and the other of 20 which is suitably attached toa flexible lead associated with the transformer or other electrical device it is desired to protect from abnormal current. The related parts of the improved cutout are connected mechanically and electrically 25 by a fuse link which is adapted to be blown by passage of abnormal current therethrough, and when this occurs in the use of the improved cutout the flexible lead freed from the restraint normally imposed thereon by an unblown fuse 30 link, swings downwardly from its normal elevated position to a lowered position thereby drawing apart the ruptured ends of the fusible element of the blown fuse link.

Fig. 1 is a side elevation of the improved cut- 35 out shown as it appears when in use in association with a power transmission line and a transformer or other electrical device, the power transmission line and a portion of the fuse link of the cut-out being shown in section and the 40 lead to the electrical device being broken away to conserve space.

Fig. 2 is an edge elevation of the part of the cut-out which is secured to the power transmission line, a portion of the fuse link being asso- 45 ciated with said cut-out part.

Fig. 3 is a section taken on line 3-3 of Fig. 1 illustrating the part of the cut-out that is associated directly with the lead of the electrical device and a portion of the fuse link.

50 Fig. 4 is a section taken on line 4- -4 of Fig. 1.

Fig. 5 is a fragmentary view illustrating the manner in which the fragment of a ruptured fuse link is detached from the part of the cutout that is associated directly with the lead of II the electrical device.

Fig. 6 illustrates a modified form of the invention wherein the part of the cut-out that is directly associated with the power transmission line is of a slightly different form and is attached to the power transmission line in a diffe'r- 5 cut manner.

Fig. 7 is a view similar to Fig. 1 but illustrating a modified form of the invention.

In the drawings, wherein are shown for thepurpose of illustration, merely, several embodi- 10 ments of the invention, A designates a transformer or other electrical device with which is associated a lead B in the form of a flexible electrical conductor. Electrical energy is normally conducted to the electrical device A from a power transmission line C through the improved cutout, which is designated generally by the reference character D, said cut-out being interposed between the power transmission line C and the lead B of the electrical device A in a manner to be hereinafter described in detail.

The cut-out D includes a terminal element l which preferably is formed from a length of heavy wire or the like. This length of wire is bent double upon itself so as to provide a pair of parallel portions 2 of substantial length, the curved bridge portion 3 which joints said parallel portions being located at the upper end of the terminal element as this part of the cut-out is illustrated in Fig. 1. In order to hold the portions 2 in their proper parallel relation a sleeve 4 is provided which embraces said portions at a point intermediate the upper and lower ends thereof. At the lower end of the terminal element I the opposite end portions of the length of wire of which this part is formed are bent back against adjacent lower portions of the parallel portions 2 to provide fuse link gripping portions 5 as shown in Fig. 1, and the upper end portions of said gripping portions 5 are bent outwardly to provide guides B that aid in the introduction of portions of the fuse link of the cut-out into engagement with the gripping portions 5. If desired the guides 6 may be provided at their outer ends with knobs 1 to give the ends of the guides a finished appearance. So as to prevent excessive outward movement of gripping portions 5 with respect to the adjacent portions of the parallel portions 2 of the terminal element l and otherwise to hold said terminal in its proper formation the lower end portion of said terminal element is provided with a cap 8 which embraces the lower end portions of said parallel portions and said gripping portions, said cap being caused to frictionally engage said parallel portions and said gripping portions so as to be maintained in place thereon.

The terminal element is attached to a wire clamp E that includes a body portion 9 provided with an outwardly extended web I II and having a suitably shaped, fixed wire-engaging jaw II. The wire clamp includes, also, an extension |2 provided with a screwthreaded opening formed therethrough through which is extended a screwthreaded wire-clamping element I3 having an eye M at its lower end. The wire clamp E includes additionally, an upper eye l5 forming a part of the body portion of the clamp which is adapted to receive a part of a clamp stick employed in elevating the clamp into engagement with the power transmission line C.

In order to secure the terminal element l to the wire clamp E the Web ID of said clamp is provided with an opening l6 which is shaped as shown to the best advantage in Figs. 1 and 4. Extended through this opening is a bolt I! which is provided with an eye portion 18, a portion of the opening being so shaped as to receive therein a portion of the eye portion of the bolt as shown in Fig. 4. The bolt has a nut 19 mounted on the screwthreaded shank thereof and said nut contacts with a face of the web of the wire clamp. To secure the terminal element I to the wire clamp E the upper portion of said terminal element is extended through the eye portion l8 of the bolt IT. The nut is then turned to draw the eye portion of the bolt inwardly of the opening I6 in the web of the wire clamp E with the result that said upper portion of the terminal element will be clamped between the face 10' of the web of the wire clamp and a portion of the inner face of the eye portion of the bolt H (see Fig. 4).

The improved cut-out includes a second terminal element'ZU which is secured to the flexible lead B associated with the electrical device A. The terminal element 20, like the terminal element I, is preferably formed from a single length of heavy wire, said length of wire being shaped to provide a pair of elongated, parallel portions 2| which are joined at one end of the terminal element by a loop 22 of substantial diameter. As shown to the best advantage in Figs. 1 and 5 the loop 22 is extended at an acute angle with re spect to the parallel portions 2| of the terminal element 20. At the end of the terminal element 20 opposite to the end thereof at which the loop 22 is located the opposite end portions of the length of wire of which the terminal element is formed are bent back against the parallel portions 2| to provide gripping portions 23 similar to the gripping portions 5 of the terminal element I. Also the gripping portions 23 of the terminal element 20 are flared outwardly at ends thereof to provide guides 24 for guiding portions of a fuse link into positions where they may be gripped by the gripping portions 23. As in the case of the guides 6 of the terminal element I the guides 24 of the terminal element 20 may be provided at their outer ends with knobs 25. The terminal element 20 is secured to an end of the flexible lead B of the electrical device A from which the insulation has been stripped as shown at B in Fig. 1, a connector F of the well known split-bolt type being shown in the drawing as the instrumentality for electrically and mechanically connecting together said flexible lead and said terminal element 20.

When in its normal operative condition the improved cut-out includes a fuse link 26 which inconductors 21 are cludes an opposed pair of electrical conductors 21 which are provided at their outer ends with eyes 28, said electrical conductors 21 having mounted thereon buttons 29 which are located immediately adjacent to the inner sides of the eyes and serve to hold said eyes in their looped condition. The inner end portions of the electrical conductors 21 are spaced apart to provide a gap and located in this gap in electrical con nection with the electrical conductors 21 is a fusible element 30. The fusible element 30 and the adjacent innerend portions of the electrical enclosed within a tube 3|, preferably formed of horn fiber or equivalent material that is characterized by the ability to give off gas in the presence of the heat of an electric are which aids in extinguishing such electric are. If desired the fuse link 26 may be provided with an expansible coil spring 32 which surrounds one of the conductors 21 and is interposed between an end of the tube 3| and an abutment 33 fixed to said conductor. The coil spring 32, which is under compression when the fuse link is in an un-- blown condition, is adapted to expand when the fusible element 30 of the fuse link is ruptured and thereby aid in the quick extinguishment of the electric are by quickly pulling the ruptured ends of the fusible element 30 apart. This coil spring 32 also draws the parts of the fuse link located Within the tube 30 taut so that looseness of said parts is prevented.

In the use of the improved cut-out disclosed herein a portion of one of the opposed electrical conductors 21 of the fuse link 26 is drawn into position between one of the gripping portions 23 of the terminal element 20 and one of the parallel portions 2i of said terminal element 20 with the aid of a suitable tool. For this purpose a switch stick of the type shown in Fig. 5 and designated by the reference character S and having a laterally extended finger S may be employed, the lateral finger of the switch stick being extended through the eye 28 of the conductor 21 being engaged by the terminal element 20 when the conductor is being pulled into gripped relation with respect to the terminal element. When the one end of the fuse link has been attached to the terminal element 20 as described, the eye 28 at the opposite end of the fuse link is engaged by the lateral finger of the switch stick and the electrical conductor 21 of which said opposite eye forms a part is drawninto gripped position between one of the gripping portions 5 of the terminal element I and one of the parallel portions 2 of said terminal element. When the fuse link is attached to the terminal element I as described the flexible lead B associated with the transformer or other electrical device A is drawn to and held in the elevated position in which it is shown by full lines in Fig. 1.

When, with the improved cut-out arranged in its normal operative position as described and as illustrated in Fig. l, a fault occurs in the electrical circuit of which the cut-out forms a part, the fusible element 30 of the fuse link will be ruptured. This will permit the flexible lead B to swing downwardly to the position Ba as shown by dotted lines in Fig. 1, said flexible lead carrying with it the terminal element 20 and the conductor 21 of the fuse link which is attached to said terminal element 20. When the flexible lead B swings downwardly as described on blowing of thefuse link the ruptured ends of the fusible element 30 of the fuse link will be pulled apart and this, together with the arc extinguishing properties possessed by thehorn fiber tube 3|, will 75 ment is accelerated by the quick expansion of the released coil spring.

In order to disengage the fragment of the fuse link from the terminal element 20 after the fuse link has blown and when the terminal element 20 is energized, the head portion of a switch stick S is extended through the loop 22 as shown in Fig. 5 so that the finger S of said switch stick extends through the eye 28 of the fragment of the fuse link. Then by pressing the head of the switch stick S downwardly into close contact with the curvature of the loop 22 and simultaneously rotating the switch stick about its axis as indicated by arrows in Fig. 5, the fragment of the fuse link may be pried upwardly out of grip-- ping relation with respect to said terminal element 2D. In the case of the terminal element I the fragment of the blown fuse link may be removed from said terminal element by merely passing the finger S' of the switch stick S through the eye 28 of the fuse link fragment and moving the switch stick upwardly to draw the fuse link fragment out of gripped relation with sai dterminal element. This is so because the terminal, element l is rigidly supported and not fixed to a flexible support as is the terminal element 20.

Instead of securing the terminal element l to the-power transmission line C with the aid ofbe secured to the power transmission line with.

the aid of electrical connectors 38 of the well known split-bolt type.

In Fig. '7 is illustrated a form of the invention which includes a terminal element 40 that is mechanically connected directly to a transformer T by means of a nut 4|. The outer, extended portion of the terminal element 40 is constructed and arranged as is the terminal element 20 previously described herein, but the opposite end portion of said terminal element extends at an angle to the outer portion thereof. Also the inner portion of the terminal element 40 is provided with an opening through which a screwthreaded stud 42 on the transformer passes, and the previously mentioned nut 41 mechanically secures said terminal element in place on said stud and provides good electrical connection between the terminal element and the transformer part to which it is attached. The fuse link 43 shown in Fig. '7 is longer than the' fuse link illustrated in Fig. 1.

Aside from the differences noted the cut-outtached to a power transmission line, a second terminal element adapted to be electrically and mechanically attached to a flexible conductor, and a fuse link electrically and mechanically connected to the first and second mentioned terl minal elements, said fuse link serving as the sole means for holding said second terminal ele ment and the flexible conductor to which said second terminal element is mechanically and electrically connected in an elevated position from which elevated position said second terminal element and the flexible conductor to which it is connected swing when the fuse link is ruptured to separate the ruptured sections of the fuse link, said fuse link being provided with eye portions at its opposite ends which are adapted to receive a tool employed to attach the fuse link to the first mentioned and the second mentioned terminal elements, and said fuse link including a tubular element formed of horn fiber which encloses the portion of the fuse link at which the rupture occurs and is adapted to give off gas when subjected to the heat of an electrical are which aids in extinguishing an electric are produced between the ruptured ends of the fuse link.

2. A cut-out comprising a terminal element adapted to be electrically and mechanically attached toa power transmission line, a second terminal element adapted to be electrically and mechanically connected to a flexible conductor, the first and second mentioned terminal elements being provided with fuse link clamping portions at the opposite sides of each thereof, and a fuse link electrically and mechanically engaged by the clamping portions of said first and second mentioned terminal elements, said fuse link servirig as the'sole means for holding said second terminal element and the flexible conductor to which said second terminal element is mechanically and electrically connected in an elevated position from which elevated position said second mentioned terminal element and the flexible conductor to which it is connected swing when the fuse link is ruptured to separate the ruptured sections of the fuse link.

3. A cut-out comprising a terminal element adapted to be electrically and mechanically attached to a power transmission line, a second terminal element adapted to be electrically and the first and second mentioned terminal elements being provided with fuse link clamping portions, and a fuse link electrically and me-- chanically engaged by the clamping portions of said first and second mentioned terminal elements, said fuse link being adapted normally to hold said second mentioned terminal element in an elevated position from which elevated position said second mentioned terminal element swings when the fuse link is ruptured to separate the ruptured sections of the fuse link, said second mentioned terminal element being provided with a portion adapted to receive and support a tool employed to remove a fragment of the ruptured fuse link from the fuse link clamping portion of said second mentioned terminal element.

4. A cut-out comprising a terminal element adapted to be electrically and mechanically attached to a power transmission line, a second terminal element adapted to be electrically and mechanically connected to a flexible conductor, the first and second mentioned terminal elements being provided with fuse link clamping portions, and a fuse link electrically and mechanically engaged by the clamping portions of said first and second mentioned terminal elements, said fuse link being adapted normally to hold said second mentioned terminal elementin an eletured fuse link from the fuse link clamping 'tioned terminal element being provided with a loop portion adapted to receive and support a tool employed to remove a fragment of the rupportion of said second mentioned terminal element.

5. A cut-out comprising a terminal element adapted to be electrically and mechanically attached to a power transmission line, a second terminal element adapted to be electrically connected to an article of electrical equipment, said first-mentioned and second-mentioned terminals including gripping portions, a fuse link mechanically and electrically engaged by the gripping portions of said first-mentioned and said second-mentioned terminals, said fuse link normally serving as a conductor for current passing between said first-mentioned and said secondmentioned terminals and adapted to be ruptured by passage of abnormal current therethrough, and tool-receiving portions forming parts of said fuse link and adapted for the reception of a tool employed in engaging said fuse link with the grippin portions of said first-mentioned and said second-mentioned terminals.

6. A cut-out comprising a terminal element adapted to be electrically and mechanically attached to a power transmission line, a second terminal element adapted to be electrically con nected to an article of electrical equipment, said first-mentioned and second-mentioned terminals including gripping portions, a fuse link mechanically and electrically engaged by the gripping portions of said first-mentioned and said second-mentioned terminals, said fuse link normally serving as a conductor for current passing between said first-mentioned and said secondmentioned terminals and adapted to be ruptured by passage of abnormal current therethrough, and tool-receiving portions forming parts of said fuse link and adapted for the reception of a tool employed in engaging said fuse link with the gripping portions of said first-mentioned and said second-mentioned terminals, said tool-receiving portions comprising loops formed at the opposite ends of said fuse link.

7. A cut-out comprising a terminal element adapted to be electrically and mechanically attached to a power transmission line, a second terminal element adapted to be electrically connected to an article of electrical equipment, said first-mentioned and second-mentioned terminals including inherently resilient gripping portions, a fuse link mechanically and electrically engaged by the gripping portions of said first-mentioned and said second-mentioned terminals, said fuse link normally serving as a conductor for current passing between said first-mentioned and said second-mentioned terminals and adapted to be ruptured by passage of abnormal current therethrough, and tool-receiving portions forming parts of said fuse link and adapted for the reception of a tool employed in engaging said fuse link with the gripping portions of said first-mentioned and said second-mentioned terminals, said tool-receiving portions comprising loops formed at the opposite ends of said fuse link.

CHARLES ADIN FOX.

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