US2115592A

US2115592A - Electric fuse device

Info

Publication number: US2115592A
Application number: US47768A
Authority: US
Inventors: Sidney R Smith
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1935-11-01
Filing date: 1935-11-01
Publication date: 1938-04-26
Anticipated expiration: 1955-04-26

Description

S. R. SMITH ELECTRIC FUSE DEVICE April 26, 1938.

Filed Nov. 1, 1935 2 Sheets-Sheet l Inventor: Sidney R. 5mit h,

Fig. (3.

6? SW is Attorney.

' April 26, 1938. s. R. SMITH ELECTRIC FUSE DEVICE Invent or:

Sidneg Filed Nov. 1

mmu

His Attorn eg- Patented Apr. 26, 1938 UNITED STATES PATENT OFFICE eral Electric Company,

York

a corporation of New Application November 1, 1935, Serial No. 47,768

20 Claims.

The present invention relates to fuse devices and has for a principal object the provision of improvements in the construction of fuse devices particularly adapted to be mounted directly on 5 the overhead line wires of a secondary electrical distribution system.

Other important objects of the invention are the provision of improved fuse devices of the type above referred to having low initial cost 10 .and low upkeep cost and which provide protection of the fuse link and other operating parts from the weather to thereby reduce maintenance care and insure efficiency and reliability of operation under all conditions; which give positive and 15 clearly observable indication of fuse operation; which are safe and easily accessible for re-fusing with provision for automatic protection of the lineman whose duty it is to service the line equipment, and which permit ready and quick installa- 20 tion thereof in almost any kind of secondary distribution system and facilitate the safe interconnecting of transformer secondaries in electrical networks.

Other objects of the invention and the manner 25 in which the invention is carried out will become apparent from the fo1l0wing..description taken in conjunction with the accompanying drawings in which Fig.'l is a sectional elevation of one form of fuse device, constructed in accordance with the ,present invention, showing the parts in the positions they assume when the fusible element is intact; Fig. 2 is aside elevation of the' device showing the parts after rupture of the fusible element, and Fig. 3 is a front elevation 35 of the device; Figs. 4 and 5 illustrate details of an improved form of fuse contact clamping device;

Fig. 6 shows in detail the parts of an improved clamping device for securing a fuse device to an electrical line conductor;

Fig. '7 illustrates diagrammatically the manner of mounting the device of Fig. 1 on a line conductor;

45 Fig. 8 shows a second form of fuse device, constructed in accordance with the present invention, with the parts thereof in the positions they assume when the fusible element is intact; Fig. 9 is a view partially cut away and partially in section of the same device showing the parts after rupture of the fusible element; Fig. 10 illustrates a section taken along the line Ill-l0 of Fig. 9, and Fig. 11 illustrates a section taken along the line H-Il of Fig. 9;

55 Fig. 12 illustrates diagrammatically the manner of mounting the device of Fig. 8 upon an electric line conductor;

Fig. 13 is a sectional elevation of a third form of fuse device, constructed in accordance with the present invention, and Fig. 14 is a partially 5 cut away view of the device showing the parts after rupture of the fusible element; Fig. 15 shows the dtails of an improved form of clamping means for securing the fuse device of Fig. 13 to a line conductor, and Fig. 16 illustrates diagrammatically the manner of mounting the device of Fig. 13 on a line conductor, while Fig. 1'7 illustrates a modified form of clamping device for securing the fuse device of Fig. 8 on a line conductor. 15

Referring to Fig. 1 of the drawings, 20 design'ates a block or box of suitable insulating material formed in two parts 2| and 22 which parts are formed with recesses cooperating to provide an explosion chamber 23 within the interior of 20 the block. The two parts of the block are secured in assembled relation in any suitable manner as, for example, by means of bolts 24 passing through aligned openings in the parts and fastened in place by means of nuts 25. The block is provided 25 with aligned passages 26 and 26' extending outwardly through the component parts thereof from the explosion chamber 23 to the opposite faces of the block.

The opposite faces of the block are provided with

recesses

21 and 21 in the upper portions of which are secured, by means of screws 2 ;the mounting plates 29 and 29' which are so fo' ed as ,to project outwardly from the recesses as illustrated and to turn up substantially parallel with the opposite faces of the block to provide flanges 30 and 30'. Also disposed one in each of the recesses 21 and 21' are plate members 3| and 3| respectively which are hingedly mounted on the mounting plates 29 and 29' as indicated at 32 and 32. These plates are arranged to abut tightly against the bottoms of the recesses and are biased outwardly to the positions shown in Fig. 2 by means of

springs

33 and 33 each of which has one end secured to its corresponding hinged plate and its other end secured to its corresponding mounting plate as shown.

On the hinged plates 3| and 3| are mounted improved fuse contact clamping devices designated generally in Fig. 1 by the numeral 34. The details of. one of these devices are shown in Figs. 4 and 5. It is to be understood that the two devices are the same in construction and hence the same numerals will be used hereinafter to designate like parts of each. Each of these clamping devices comprises a cylindrical boss 35 fixedly mounted in an opening 36 in the plate 3|, or 3| as the case may be, in any suitable manner as by means of the riveted connection indicated at 31, and an annular member 38, which is mounted on the boss 35 for coaxial rotation thereabout. Boss 35 is provided with a longitudinal opening 39 eccentric of the axis of the boss and is provided also with an annular recess 40 adjacent the point of connection of the boss to the plate 3 l. Member 38 has an internally projecting flange 4| arranged to move in the recess 49, the inner rim of the flange being eccentric to the axis of rotation of member 38, with portions of the rim, such as those designated 42, having a greater radial distance than other portions such as that designated at 43. The recess 48 is soformed over a portion of the extent thereof that it intersects or opens into the passage 39 and hence the eccentric rim 4| of member 38 projects into the passage 39 to varying degrees in accordance with the distance of the rim portion from the axis of rotation. Plate 3! and the riveted over portion 31 of the boss 35 have an opening 44 formed therein in substantial alignment with the passage 39.

In order to clamp a wire or like tubular element to the plate 3i by means of the clamping device 34, member 38 is turned to such position that the rim portion 42 thereof is in proximity with the opening 44. This rim portion, which has the greater radius, does not project into the passage 39 and the wire may therefore be inserted into the opening 44 and the passage 39 without obstruction being offered thereto. The member 38 is then rotated on the boss 35 to cause the lesser radius flange portion 43 to project into the passage 39 and the wire isclamped thereby between the rim of the flanged portion and. the opposite wall of the passage 39. In order to effect an even more efiicient clamping connection, the rim of the flange may be slightly sharpened to enhance its grip upon the surface of the wire.

With the apparatus previously described, the mounting of the common types of fuse link in the block 20 becomes a very simple matter. The fuse link is inserted through one of the passages 26 or 26' and is so located that its fusible portion 45 is disposed within the explosion chamber 23.

The fuse link may or may not be provided with a strain wire 46 as found desirable. The connection shanks or contacts 41 of the fuse link protrude outwardly through the passages 26 and 26' for engagement by the clamping devices 34 carried by the plates 3| and 3|. Members 38, which preferably are knurled, of the clamping devices, are turned as previously described to such positions that when the hinged plates are pressed into abutting engagement with the faces of the block 20. the shanks 47 project through the openings 44 into the passages 39 of the clamping devices; Members 38 then are rotated to bring the rim portions 43 thereof into engagement with the shanks to thereby effect a secure clamping engagement thereof.

It will be seen that with the arrangement just described the fusible portion 45 and the end shanks or contacts 41' of the fuse link are substantially completely enclosed within the chamber 23 and the passages 26 so that they are effectively protected from all weather conditions, the inner surfaces of the plates 3| and 3| serving to eifectively close the outer ends of the passages 26 and 26 respectively. The tensioned fuse link acts in opposition to the biasing force Of the springs 33 and 33' to maintain the plates 3| and 3| in their innermost positions.

In order to mount the fuse device upon an electric line conductor, an improved removable clamping means is provided which is designated generally in Fig. 1 by the numeral 48, the details of the clamping means being shown in the ex ploded view of Fig. 6. As will be seen from Fig. 6, the clamping means consists essentially of a supporting plate 50, a resilient plate 5|, a clamping plate 52, guide means for maintaining the three plates in proper assembled relation and screw means for drawing the clamping plate and the supporting plate together. Supporting plate '59 is provided with openings 53 for receiving screws 54 which serve to fasten the plate firmly to the flange 30' of the mounting plate 29 secured to the block 29. Plate 52 is formed with a. bent over flange or U-shaped portion 55 which is arranged to fit over the edge 56 of a curved portion 57 of the supporting plate 50 to thereby provide a hinged connection Plate 5| is formed to flt between the

plates

50 and 52 and is provided with a bent over flange portion similar to that of plate 52 and having a projection 58 adapted to extend between the curved portion 51 of plate 50 and the plate 52 and having also projections 59 which extend between the curved portion 51 and the downwardly projecting portion of the bent over flange 55. This resilient plate 5| acts to swing the plate 52 outwardly away from the plate 50 about the hinged connection. An eyebolt 69 is provided for drawing the

plates

59 and 52 together in opposition to the action of the resilient plate 5|. This bolt has a bearing flange 6|, which abuts against the outer face of plate 52, and a threaded portion 62 which extends through openings in the two

plates

50 and 52 into engagement with a screw threaded nut 63 secured in any suitable manner to the outer face of plate 50. The two

plates

50 and 52 are provided with

depressions

84 and 65 respectively which cooperate to receive a wire as shown in Fig. 1, and plate 52 is provided with a portion 66 which is bent outwardly to aid in guiding the wire into the

recesses

64 and 65. Plate 52 is provided with two projecting pins 61 and 68 which are arranged to extend into

openings

69 and 10 respectively provided in the between the two plates.

plate 50 to thereby maintain the plates in properly assembled relation. The clamping means just described serves not only as a supporting means for the fuse device but also provides electrical connection between the wire engaged thereby and the flange 30' of plate 29' conductive relation with the fuse contact clamping device 34.

Other clamping means are mounted on the block 20 for securing an electric lead Wire or line conductor thereto in conductive relation with the other fuse contact clamping device 34, and comprise a U-shaped member H the two legs of which are adapted to be fastened onto the block 20, one disposed on each side of the flange 30 of the supporting plate 29, and to be held in place by means of screw 12 and lock washers 13. A screw 14 in threaded engagement with an opening in the U-shaped member serves to rigidly clamp a. feed wire or line conductor within the closed portion of the U-shaped member as shown.

In an electrical distribution system the fuse device previously described is adapted to be mounted upon a line conductor and either connected across a strain insulator or used with or without an insulator in conjunction with a rack which is in electrical or cross arm assembly. Fig. '1 shows, for example, the manner in which the device may be connected across a strain insulator, designated by the numeral 16, to which are connected the line conductors 11 and 18. Before the fuse device is mounted upon the line conductor, a fuse link is installed therein in the manner illustrated in Fig. l with the clamping devices 34 securely engaging the ends of the link so that plates 3| and 3! are held in their inward positions. Also, eyebolt 60 of the clamping means 48 is screwed outwardly so that the clamping means may be slipped easily over a bared section 18' of the line conductor 18, the curved portion 66 of the clamping plate 52 serving as previously outlined to guide the conductor into the

recesses

64 and 65 of the

plates

50 and 52 respectively. During the mounting operation the fuse device may be supported in any suitable manner as by means of a switch stick the end of which is inserted through the eyelet of eyebolt 60. When the fuse device has been mounted upon the line conductor, bolt 60 is turned to draw the

plates

50 and 52 together and thereby effect a rigid and non-movable engagement of the clamping means with the. bared section 18 of the line conductor, one end of the fuse link thus being electrically connected to the supporting line conductor 18 through the right hand (as viewed in Fig. 1) clamping device 34, hinged plate 3|, mounting plate 29', and supporting plate 50. As a final operation, the end 11', previously bared, of the line conductor 11 is inserted through the opening in the U-shaped member 1| and tightly clamped in position by means of screw 14 thus providing electrical connection from line conductor 11 through clamping member 1|, mounting plate 29, hinged plate 3|, and the left hand clamping device 84 to the other end of the fuse link. The sequential mounting operation just outlined is made possible by the improved arrangement of the parts of the fuse device and mounting means therefor and is an important safety feature giving added protection to a lineman either installing the device for the first time or re-fusing the device after operation thereof.

In operation, blowing of the fuse link results in the formation of an arc and the production of gases in the explosion chamber 23 which creates a pressure in the chamber tending to blow the gases outwardly through the passages 28 and 26. The result is that the plates or doors 3| and iii are blown outwardly to effect separation of the fuse shanks or contacts 41.

Springs

33 and 33 aid in this outward movement of the doors and also serve to maintain the doors in their outward positions after rupture of the fuse link to give a positive and clearly observable indication of the operation of the device. Collection of ice, sleet and other undesirable foreign matter upon the working parts of the fuse device in a manner to impair the emciency and dependability of operation thereof is prevented by the substantially complete enclosure of the fuse link within the chamber 23 and the passages 26 and 26', by the closing of the ends of the passages by means of the plates 3| and BI and by the mounting of the plates in such manner that they normally repose in the bottoms of the recesses 21' and 21' respectively in the opposite faces of the block or casing 20. Furthermore, the two

clamping devices

48 and 1| provide under all weather conditions effective means for electrically connecting the fuse contacts to the respective line conductors.

As will be understood from the preceding description, re-fusing of the device may be accomplished readily and quickly by first removing the lead wire or bared conductor end 11' from the clamp 1i and then unscrewing the clamping means 48 whereupon the fuse device may be lifted from the supporting line conductor and may be conveniently re-fused without danger to the lineman.

The second embodiment of improved fuse device illustrated in Figs. 8 to 11 inclusive consists essentially of a short fuse tube of suitable insulation material having a two-part terminal cap 8| mounted on the upper end thereof and a combination electric lead and fuse terminal clamping cap 82 connected to the other end thereof by means of an insulating tube or casing 83. The lower end of the tube 80 is telescoped within and longitudinally slidable with respect to the upper end of the casing 83 as more clearly shown in Fig. 9. A coil spring 84, surrounding the tube 80 and having its lower end seated in a recess 85 of the casing 83 and its upper end in abutting engagement with the lower surface of the terminal cap 8|, serves to bias the two tubes apart into extended positions while pins or screws 86, mounted on the outer surface of the tube 80 and movable in slots 81 formed in the inner surface of the tubular casing 83, serve to limit the relative movement between the telescoped tubes. These screws 86 and cooperating slots 81 also serve to prevent relative rotation of the tubes about their common axis.

Terminal cap 8| serves not only as a fuse contact but also as a means for supporting the fuse device on an electric line conductor. To this end, it is provided with an inner cap 90 screwed onto the upper end of the tube 80 and having an outer screw threaded portion for removable connection to an inner screw threaded portion of a supporting cap 9|. A lock washer 92 is provided for insuring a tight connection between the inner cap 80 and the end of the fuse tube 80 while the cap 90 has a centrally disposed opening for the accommodation of the shank 93 of a button head type fuse link, the button head 94 of which is clamped between the caps 90 and Hi. It is to be understood that, with slight modification well within the range of mechanical skill, the fuse device may be adapted for other well known forms of fuse links.

On the upper end mounted a clamping device for securing the fuse device to a line conductor. A preferred form of such clamping device is illustrated in Figs. 8 and 9 and comprises a stud member 95 extending upwardly from the cap SI and having a transverse slot 96 for the reception of an electrical conductor as illustrated. In order to hold the conductor in the slot 96, the outer surface of the stud is provided with a screw threaded portion for engagement with a clamping nut 98 which upon being screwed downwardly presses against the metal clip 99 and effects a tight clamping engagement upon the conductor.

An alternative form of clamping means is illus trated in Fig. 1'7. In this case the outer supporting cap I80 cf the two-part terminal cap mounted on the end of tube 88 is formed with an arm IOI extending outwardly at one side thereof substantially at right angles to the tube and a downwardly curved guide portion I02 extending outwardly at the other side thereof. This guide portion curves inwardly to a depression I03 which is provided adjacent the button cap 94 of the fuse link for the accommodation of a line conductor in engagement with the button cap. At the outer end of the arm IN is hingedly mounted a clamping arm I04 arranged to extend in substantially parallel relation with the arm IM and having a recess I05 for cooperation with the recess I03 of the cap I00 to clamp the conductor therebetween and having also an upwardly curved portion I06 for cooperation with the curved portion I102 to guide the conductor into the recesses. In order to securely clamp a conductor, such as that indicated at ill, in the recesses I03 and I05, an internally threaded wing nut I 01 is rotatably mounted in an opening I00 in theclamping arm I04 and is arranged to engage a screw threaded element I09 pivotally mounted on the arm IOI as indicated at H0.

Tubular casing 83, of the device illustrated in Figs. 8 and 9, has formed thereon an annular flange or skirt ill for preventing electrical creepage and has mounted on the lower end' thereof the clamping terminal cap 82 which is secured in place by means of screws H2 which extend through openings in the terminal cap and into openings provided in the wall of the casing 83 as clearly illustrated in Fig. 10. This lower terminal cap has a centrally located opening II3 in alignment with the passages in the tubes 00 and 83 for the reception of an extension H4 of a fuse link extending through the telescoped tubes. When the fusible portion H5, and the strain wire II6 if such be provided, of the fuse link are intact and the tubes and 83 are in contracted telescoped relationship, the extension II4 of the fuse link extends into the opening H3 where it is securely fastened by means of clamping screw II! which is mounted in a screw threaded opening H8 extending through the sides of the cap 82 as shown in Fig. 11. An observation opening H9 also is formed in the terminal cap at right angles to the opening H8 to facilitate the clamping of the fuse extension. The terminal cap has also exhaust ports I20 in communication with the interior of the casing 83 for the release of gases therefrom upon the blowing of the fusible element.

A clamping stud member I 2I, similar to that provided on the upper supporting cap 9|, is

formed on the lower cap 82 and has a transverse slot I22 for the reception of a wire conductor and a metallic clip I24. The stud is externally screw threaded to provide for the screwing thereon of a clamping nut I25.

The installation of the fuse device illustrated in Figs. 8 and 9 is similar to that of the first embodiment-previously described and similarly it may be either connected across a strain insulator or mounted with or without an insulator 'in a rack or crossarm assembly in a distribution system. In the mounting of the device in the manner illustrated in Fig. 12, the supporting cap 9| -or the supporting cap I00, as the case may be, is first unscrewed from the terminal cap 80 and is then secured to the bared portion I26 of a line conductor I26 which is fastened at its end to a strain insulator I21. It will be seen that the clamping means illustrated in Figs. 9 and 17 both are effective when properly clamped to prevent rotation of their associated supporting caps about their longitudinal axes. If desired, however, the clamping means may be made rotatable with respect to the supporting cap, but the rigid construction is usually to be preferred. A fuse link, which may be of any suitable form and which is illustrated as being of the button cap type. is inserted into the fuse tube 80 through the opening provided in the terminal cap 80 and, with the

tubes

80 and 83 compressed, the lower end or extension H4 of the fuse link is clamped in the central opening H3 of the lower terminal cap 82 by means of the clamping screw II'I so that the tubes are maintained in contracted telescoped relationship in opposition to the biasing force of the coil spring 84. The fuse device is then ready to be connected to the supporting cap Si or I00, as the case may be, by screwing the cap into the supporting cap as previously outlined. The bared end I28 of the other line conductor I28 is then inserted into the slot I22 of the lower cap 82 and securely clamped in place by means of the metal clip I24 and the clamping nut I25. An important feature of this last described device is that, due to the prevention of relative rotation between the tubes 00 and 83 and due to the slotted construction of the stud i2I, it is impossible to screw the upper terminal cap 00 of the fuse tube 80 into the supporting cap mounted on the supporting line conductor if the other line conductor has previously been clamped to the lower terminal cap 82. Added safety to the lineman installing the fuse device is thereby insured in that the final act of the installing operation is necessarily the simple insertion of the lead wire or conductor end I28 into the lower terminal clamping means and the danger of coming in contact with both of the terminals of a live fuse element is thereby avoided.

The advantages of the fuse device just denection with the embodiment first described in that the fuse link is at all times enclosed within a chamber formed in the interior of the telescoped tubular members and is therefore protected from all sorts of weather conditions. Furthermore, danger of non-operation of the fuse device due to formation of ice or sleet coating on the operative parts is guarded against by the abutting engagement of the upper terminal cap BI with the upper end of the casing 83 when the fuse link is intact, which engagement insures substantially complete enclosure of the inner slidable fuse tube 80 and the biasing spring 84. A positive indication is also given upon rupture of the fuse link by the springing apart of the telescoped tubes into their extended relationship. If desired, the outer surface I29 of the fuse tube 80, which is exposed upon operation of the fuse device, may be painted red or some other bright color to accentuate and make more readily observable from the ground the indication of the fuse rupture. Efiicient operation of the fuse device is insured in that the explosive force of the gases given off in the interior of the tube and the forcing apart of the fuse terminals by the spring facilitates the quenching of the arc formed upon rupture of the fuse element, and the exhaust ports I20 in the lower terminal cap serve to relieve the pressure within vent rupture thereof.

A third form of improved fuse device embodying the present invention is illustrated in Figs. 13

and 14 and comprises a fuse tube I30, of suitablethe tubes and preclamping screw I33 extending through a threaded opening in the side wall of the terminal member is provided for clamping the end of the fuse link against the inner side wall of the terminal member. The outer end of the terminal member is formed to permit a plug and sleeve connection to an electric lead wire and to that end has a central bore I34 for the accommodation of a bifurcated plug I35, which plug has a bore I36 in the end thereof for the accommodation of a line conductor or electric lead wire. The plug is secured to the terminal memberby means of a screw I31 extending through an opening in the side wall of thcbore I34 and into engagement with the plug while the conductor or lead wire is secured in the bore I36 of the plug by means of screws I38.

The other end of the fuse tube I30 is provided with a terminal cap I40 having a central bore I for the accommodation of the other end I42 of the fuse link and has a clamping screw I43 extending through an opening in the wall of the bore for clamping the end of the fuse link therein. Terminal cap I40 has also an annular flange portion I44 which fits over the end of the tube I30 and cooperates with the body of the terminal'cap for substantially closing the end of the fuse tube, the bore I4I being restricted by the end of the fuse link and the end of the clamping screw projecting thereinto.

Referring to Fig. supporting member, the legs of which are provided with inner facing concave portions I46 and I41 which cooperate to engage the outer surface of the fuse tube I30. These curved portions are clamped tightly upon the fuse tube by means of a bolt I48 extending through openings in the ends of the legs of the U-shaped member and having a clamping nut I40 threadedly engaging the end thereof. One or both of the curved portions I46 and I41 may be provided, if desired, with an internal projection I50 which engages a depression formed in the outer surface of the fuse tube to thereby prevent rotation of the fuse tube in the supporting member.

Slidably mounted on the outer end of the supporting member I45 is a U-shaped clamp Il having one leg I52 thereof, which is longer than the other leg I53, held in slidable engagement with the supporting member I45 by means of a guide ring I54 surrounding the leg I52 and a portion of the member I45. A wing screw I55 extending through aligned openings I56 and I51 in the ends of the U-shaped members I5I and I45 respectively, engages a clamping nut I50 disposed interiorly of the member I45, and serves to clamp an electric conductor between the ends of the two U-shaped members as shown.

Rigidly clamped between the end of the member I45 and the clamping nut I50 supported thereby are the ends of a metallic spring strip I60 and a metallic conducting strip I6I the other ends of which strips are secured to theterminal cap I40 as indicated in Fig. 13. Spring strip I60 is operative to bias the terminal cap from its closing position shown in Fig. 13 to its outward position shown in Fig. 14 and conducting strip I6I serves to electrically connect the terminal cap I40 with the supporting clamping means and the line conductor.

In Fig. 16 is illustrated diagrammatically the manner of connecting the fuse device last described across a strain insulator I62 to which are connected the line conductors I63 and I64 of an overhead distribution system. In order to carry 15, I45 designates a U-shaped.

out the mounting operation, a fuse link is inserted into the open end of the fuse tube I30, the plug I35 having been previously removed from the bore I34 of the terminal I3I and the terminal cap I40 being in the position illustrated in Fig. 14. The lower end I32 of the fuse link is securely clamped in the central bore of the terminal I3I by means of the clamping screw I33. Terminal cap I40 is then bent downwardly into closing relation with the end of the tube I30 and the other end I42 of the fuse link is secured in the terminal cap by means of clamping screw I43. The assembled fuse device can then be mounted upon the line conductor I63 with the bared portion I63 of the line conductor extending between the U-shaped supporting member I45 and the U-shaped clamping member I5I, the wing screw I55 being turned until the conductor is securely clamped between the U-shaped members. Connection plug I35 withthe bared end I64 of the other line conductor I64 connected thereto is then inserted into the socket or bore I34 of the terminal member I3I and the fuse device is in condition for service. Upon rupture of the fuse element the combined action of the spring strip I60 and the gases generated within the tube I30 causes the terminal cap I40 to move rapidly outwardly to the position shown in Fig. 14 to thereby increase the distance between the fuse terminals and facilitates the extinguishing of the arc therebetween.

The advantages of the last described fuse device construction are similar to those attendant upon the use of the two previously described embodiments ,in that the device is simple and easy to manufacture, may be installed and serviced with ease and safety, is eflicient and reliable in operation under all weather conditions due to substantially complete enclosure of'the fuse link within the enclosed chamber, and gives a positive indication clearly observable from the ground of fuse operation.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. A fuse device of the enclosed type adapted to be suspended from an electric line conductor and including in combination an, insulating casing having a passage extending therethrough and a pair of terminal members one at each end of the passage for supporting a fuse element in the passage, one of said members being arranged to substantially close the end of the passage adjacent thereto and having mounting means including a resilient element operative to move said one element outwardly to an indicating position -upon rupture of said fuse element, means for electrically connecting said terminal members respectively to said line conductor and to a second electrical conductor and means for mounting the casing on the line conductor including a clamping device removably engageable with the line conductor.

2. A fuse device adapted to be supported by an electric line wire and including in combination an insulating casing formed to substantially completely enclose a fuse element with the ends of the element projecting outwardly through openings in opposite sides of the casing, a pair of outwardly biased spring actuated fuse contact clamping devices hingedly mounted one on each of said opposite sides of the casing and each arranged to engage a protruding end of said fuse element, means carried by said casing for removably mounting the casing on an electric line wire and for providing electric connection between the line wire and one of said contact members, and other means carried by said casing for engaging an electric lead wire and for providing electrical connection between said lead wire and the other one of said contact devices.

3. A fuse device adapted to be suspended from an electric line wire including in combination a block of insulation material having a recess in the interior thereof to provide an explosion chamber and having passages extending outwardly from said chamber to two opposite faces of the block, a pair of outwardly biased spring actuated metallic plate members hingedly mounted one on each of.

said opposite faces of the block and each arranged when in inward position to substantially close the outer end of one of said passages, fuse contact clamping means carried by each of said plates for engaging an end of a fuse link disposed in said chamber with its ends projecting outwardly through said passages, means for supporting said block on an electric line wire including a clamping device removably engageable with the line wire and mounted on the block in conductive relation to one of said plates, and other clamping means mounted on said block in conductive relation to the other of said plates for electrically connecting a second electrical conducting wire thereto.

4. In a clamping device for engaging a wire or like tubular element, a pair of members mounted in substantially abutting relation and relatively rotatable about a common axis, each of said members having an opening therein eccentric with respect to said axis and said openings being so disposed with relation to each other that when said members are in certain relative positions the openings provide a passage for the loose accommodation of said aforementioned tubular element and that when said members are in certain other relative positions portions of the rims of the openings cooperate to clamp said tubular element tightly therebetween.

5. In a clamping device for engaging a wire or like tubular element, a substantially cylindrical member having a passage extending longitudinally therethrough eccentric with respect to the axis of the member, said member having also an annular recess formed in the outer surface thereof with the recess for a portion of the extent thereof opening into said passage, and an annular member mounted on said first member for rotation thereabout and having an inwardly projecting flange movable in said recess, the inner rim of said flange being eccentric with respect to the axis of said members and being arranged when said second member is rotated into predetermined positions with respect to said first member to project into said passage to cooperate with the wall of the passage for tightly clamping such aforementioned tubular element therein.

6. Means for removably mounting an electric device on a line wire or the like comprising a pair of substantially fiat plates arranged in side by side relationship with one of the plates hingedly connected along one of its edges to the corresponding edge of the other of the plates, said plates having formed therein at a distance from the said hingedly connected edges thereof jaw portions arranged to engage a line wire or the like, at least one of said plates having formed on the edge thereof opposite to its hingedly mounted edge a curved portion for guiding a line wire or the like into engagement with said jaw portions, a resilient element disposed between the plates tending to force the same apart, a clamp- ,arranged to fit over said edge portion to provide a hinge connection between the plates when they are disposed in side by side relationship, said plates having cooperating guide means for maintaining them in properly assembled side by side relationship and having also cooperating jaw portions for engaging a supporting member, a resilient member formed to fit over the said edge portion of said first plate and beneath the bent over flanged portion of said second plate and operative to swing said second plate away from said first plate about said hinged connection and screw means operatively engaging said plates for adjustably drawing the same together to clamp said supporting member therebetween.

8. A fuse -device including in combination a pair of tubular members at least partially telescoped one within the other and longitudinally slidable with respect to each other, a pair of terminals carried one by each of said members, each of the terminals having means for anchoring one end of a fuse link which extends through said members and serves to maintain the members in contracted telescoped relationship by the tension of the fuse link, means for effecting longitudinally outward movement of at least one of said members with respect to the other upon rupture of a fuse link extending between said terminals, a clamping device secured to one of said members in electrical conductive relation with the terminal carried by the last mentioned member and arranged to engage an electric line wire for supporting the fuse device thereon, and means carried by the other of said members for securing a second conductor in electrical conductive relation with the terminal carried by the said other of the members.

9. A fuse device including in combination a pair of tubular members at least partially telescoped one within the other and longitudinally slidable with respect to each other, a pair of terminal caps mounted one on the outer end of each of said members and each having means for anchoring one end of a fuse link extending through said members, means operative upon rupture of said fuse link for effecting relative movement between said members to give indication of the rupture of the link, a supporting device connected to one of said members in electrical conductive relation with the terminal cap mounted thereon and having clamping means for engaging an electric line wire, and clamping means carried by the other of said caps for securing an electric lead wire thereto.

10. A fuse device including in combination a fuse tube having a terminal cap on one end thereof, a tubular casing having one end slidably telescoped over the end of said tube opposite to said cap and having a second terminal cap mounted on the outer end thereof, means carried by said caps for engaging the ends of a fuse maintain the tube and casing in telescoped relationship, means operative to force the tube and easing apart upon rupture of said fuse element, means for limiting the relative movement of the tube and casing, a supporting member removably secured to one of said caps and having means for fastening onto an electric conductor, and clamping means carried by the other of said caps for engaging a second electric conductor.

11. A fuse device including in combination, a pair of tubular members at least partially telescoped one within the other and slidable longitudinally outward with respect to each other, a pair of terminal caps secured one to the outer end of each of said members and each having means for anchoring one end of a fuse link extending through said members, means operative upon rupture of said fuse link for effecting relative movement between said members, clamping means carried by one of said terminal caps for effecting engagement with an electric lead wire, and means for mounting the fuse device on an electric line wire including the other of said terminal caps and a supporting member removably fastened to the last mentioned cap and having a clamping device for removably engaging the electric line wire.

12. In a fuse device, the combination of a fuse tube having a two-part terminal cap, the parts of said cap having cooperating threaded portions for removable connection thereof, one of said parts being fixed to one end of said tube and having means for supporting one end of a fuse link disposed in thetube and the other of said parts having means for fastening the same to an electric conductor, a second tube disposed telescopically about and longitudinally slidable with respect to said first fuse, means for preventing relative rotation of said tubes about their common axis, and a second terminal cap mounted on the end of said second tube opposite to said first terminal cap and having means for effecting clamping engagement with the other end of said fuse link and with a second electric conductor.

13. In a fuse device, the combination of a fuse housing, a terminal cap adapted to be secured to one end of the housing, said cap and said one end of the housing having cooperating screwthreaded portions for the removable connection of the housing to the cap by rotation of the housing relative to the cap about the axis of said screw-threaded portions, said cap having means for clamping'the same on an overhead line wire or the like and for preventing rotation of the cap on the line wine or the like about the axis of said screw-threaded portions,'and clamping means for securing a conductor to the other end of said housing with the conductor extending transversely with respect to the axis of said screw-threaded portions, thereby to render extremely difficult the rotation of the housing to connect the said one end thereof to said cap when the cap is clamped on an overhead line wire or the like and a conductor is secured to the said other end of the housing by said second-mentioned clamping means.

14. In a fuse device, the combination of a fuse housing having means at opposite ends thereof for anchoring the respective opposite ends of a fuse link extending through the housing, a terminal cap on one end of said housing arranged to prevent access to the said anchoring means at said one end of the housing, said cap and said one end of the housing having cooperating screwthreaded portions for the removable securing of the cap to the housing by relative rotation of the cap and housing about the axis of said screwthreaded portions, and clamping means carried respectively by said terminal cap and by the other end of said housing for securing thereto respectively a pair of conductors with the conductors extending transversely with respect to the axis of said screw-threaded portions, thereby to necessitate disconnection of a conductor from at least one of said clamping means in order to permit rotation and removal of said cap from said one end of the housing for installation or removal of a fuse link.

15. In a fuse device of the type adapted to be suspended from an electric line conductor, the combination of a fuse tube having a bore for the accommodation therein of a fuse link, a terminal cap mounted on one an opening in alignment with the bore in said tube for the passage therethrough of a fuse link, the rim of said opening being adapted to support the button-head terminal of a button-head type fuse link, and a clamping device carried by said cap arranged to engage a line conductor for supporting said fuse tube on the line conductor, said clamping device having means for maintaining the supporting line conductor in firm engagement with a fuse link button-head terminal resting on the rim of said opening.

16. A terminal device adapted to be mounted on the end of a fuse tube including in combination a pair of cap members one tightly secured to the end of the fuse tube and having means for anchoring one end of a fuse link disposed in the tube and the second of said cap members being removably secured to said first cap member, said cap members having also registering openings.

for the outward projection therethrough of said one end of said fuse link and said second cap member having a depression adjacent the opening therein for accommodating a wire conductor in conducting engagement with the projecting end of said fuse link, a clamping arm hingedly mounted on said second member to swing into engagement with said wire conductor, cooperating guide means on said arm and said second member for guiding said wire conductor into said depression, and adjustable means for forcing said clamping arm into engagement with said wire conductor to clamp the said conductor in said depression.

17. A fuse device including in combination, a fuse tube having terminal members disposed at opposite ends thereof for supporting a fuse element extending through the tube, one of said members having means providing for the quick detachable connection of an electric lead wire thereto and the other of said members being removable from the end of the tube, means carried by said tube for removably mounting the tube on an electric line wire and for electrically connecting said removable terminal member to the line wire, and spring means operative to effect movement of said removable terminal outwardly from the end of the tube to an indicating position upon rupture of said fuse element.

18. A fuse device including in combination a fuse tube having a pair of terminal members mounted one at each end of the tube for supporting a fuse element in the tube, at least one of said terminal members being movable with respect to the end of the tube adjacent thereto and the other of said terminals having means for connecting an electric lead wire thereto,

end of said tube and having s means for mounting said movable terminal member including a metallic spring strip operative to eiTect outward movement of the movable member to an indicating position upon rupture of said fuse element, and means for supporting said tube and terminals on an electric line wire including a clamping device detachably engageable with the line wire and, connected to said tube and to said. spring strip.

19. In combination, a fuse tube having a terminal at one end thereof provided with means for engaging one end of a fuse element extending through the tube, means for detachably securing said tube to an electric line wire and for electrically connecting said terminal to the line wire, a terminal member secured to the other end of said tube and having a longitudinal bore in communication and substantially axial alignment with the interior of said tube, means for clamping the other end of said fuse element in said bore, and means for efiecting quick detachable connection of a wire conductor to said terminal member including a hollow sleeve formed on the outer end of said terminal member and than the other leg thereof, means for mounting said second U-shaped member on said first Ushaped member with the closed end of the second member exteriorly of and substantially parallel with the closed end of the first member, and with the longer leg of said second member in substantially parallel slidable engagement with one of the legs of said first member, and adjustable screw means interconnecting said members for drawing the closed ends thereof together to clamp said line wire therebetween.

SHENEY B. SMITH.