US2226838A - Fuse construction - Google Patents

Description

Dec. 3l

, 1940. H. A. TRIPLl-:TT 2,226,838

FUSE CONSTRUCTION 4 Sheets-Sheet 1 Filed Aug. 5, 1938 Dec. 31, 1940. H A, TRlPLElpT 2,226,838

FUSE CONSTRUCTION Filed Aug. 5, 1938 4 sheets-sheet 2 Dec. 31, 1940. A TRlPLETT 2,226,838

FUSE CONSTRUCTION Filed Aug. 5, 1958 4 sheets-'sheet s (nfl. W www liever?? @f1 @fyi 27. Z772?) Ze Dep. 31, 1940.`

H. A. TRIPLETT FUSE CONSTRUCTION Filed Aug. 5, 1938 4 Sheets-Sheet 4 Patented Dec. 31, 1940 l UNiTED STATES PATENT OFFICE FUSE CONSTRUCTION Hugh A. Triplett, Wilmette, Ill., assignor to Schweitzer & Conrad, Inc., Chicago, Ill., a. corporation of Delaware Application lAugust 5, 1938, Serial No. 223,175 39 Claims. (Cl. ZOO-117) My invention relates, generally, to circuit intermovable contact engaging portions of the lower rupters and it has particular relation to expulsion contact assembly of a hinged type of fuse dropfuse devices of the dropout type. out and at the same time provide a relatively 'I'he present invention constitutes an improvehigh degree of contact pressure between it and ment over the dropout fuse construction shown the lower terminal of the fuse tube. 5 in the copending application of Allan Ramsey, The fuse link shown in said copending appli- Serial No. 740,057, filed August 16, 1934, and ascation is provided with a iiber tube that is sesigned to the assignee of this application. It also cured to a terminal which, in turn, is connected provides a fuse construction that has a greater to a tension spring in the fuse tube. When the range of current interrupting capacity and is fusible element in the fuse link blows, the ter- 10 adapted for use on higher system voltages, i. e., minal and the fiber sleeve of the fuse link are up to 46,000 volts. However, this figure is not drawn into the fuse tube by the spring. In some intended to represent the limit of system voltage cases the arc is first formed within the sleeve to which the invention may be applied but is of the fuse link and then is drawn into the bore l5 merely illustrative of its range of application. of the fuse tube which is of considerably larger 15 lIn this copending application of Ramsey a fuse diameter. Under certain operating conditions tube is provided that is hinged on a lower stadifficulties may be encountered in quickly extionary terminal and is latched at the top to tinguishing the arc. It is an object of my inanother stationary terminal. Ihe stationary vention to hold the sleeve of a fuse link or fuse terminals, are, of course, connected to the circuit cartridge with its lining of arc extinguishing 20 to be protected. The fuse tube is of the expulmaterial stationary relative to the fuse tube when sion type and has positioned therein a fuse link the fusible element blows. It is also an object containing a fusible element that blows under of my invention to open a circuit by drawing an predetermined conditions of overload on the cirarc in a bore of substantially uniform diameter cuit. As long as the fuse link remains intact, in a lling of arc extinguishing material to ex- 25 the fuse tube is held in position because of the tinguish the same and subsequently automatically latch at the upper end. On blowing of the fuse providing an air gap in the circuit in addition link, the latch is released and the tube is perto that formed as a result of extinguishing the are. mitted to rotate about its lower end to an open The fuse link in said copending application is Circuit position. thereby placing an air gap in provided with a flexible leed that extends outside 30 the circuit in addition to that formed by blowing 0f the fuse tube and is arranged t0 be secured of the fusible element- The upper terminal aS- to the lower terminal of the fuse tube. In re- SeInblY iS DIOVded With a pail Of Contact ngers fusing the fuse tube, the flexible lead is drawn that are rigidly secured t0 the upper Stationary to a predetermined position where its wedge terterminal and are iiared outwardly and upwardly minal can be inserted in a pair of jaws. An ob- 35 at their outer ends for Contact engagement with ject of my invention is to automatically latch a OPDOSte Sides 0f the Upper terminal 0f the fllSe fuse cartridge or fuse link in place in a dropout tube. This construction requires that there be type 0f fuse tube on its being drawn to a prefairly CIOSe alignment between the fllSe tube Or determined position therein. Still another object its lower support and the upper contact assembly. of my invention is to latch the fuse cartridge or' 40 One of the objects of my invention is to provide fuse link having a flexible lead in a fuse tube in for receiving the upper terminal of the fuse tube such manner that there is no tension stress apof a hinged type of dropout in order to accomplied to the flexible lead. A still further object modate a fairly wide range of misalignment beof my'invention is to provide for manually re tween the upper contact assembly and the fuse leasing the latch so as to permit removal of the 45 tube support. fuse cartridge or fuse link either before or after The lower contact assembly shown in said coit has blown. pending application is provided with a contact Other objects of my invention will, in part, be linger that is backed up by a spring and is arobvious and in part appear hereinafter.

ranged to engage a contact arm carried by the Accordingly, my invention is disclosed in the 50 lower terminal of the fuse tube. The arrangeembodiment thereof shown in the accompanying ment is such that this contact iinger may be drawings and it comprises the features of conbent out of shape or otherwise distorted by accistruction, combination of elements and arrangedental engagement by a switch stick or the like. ment of parts which will be exemplied in the It is an object of my invention to protect the construction hereinafter set forth and the scope 55 of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of my invention, reference may be had to the following detailed description, taken in connection with the accompanying drawings in which:

Figure 1 is a view, in side elevation, of a dropout fuse device of the expulsion type constructed in accordance with my invention;

Figure 2 is a view, in front elevation, of the fuse device shown in Figure l;

Figure 3 is a view, in side elevation, of the lower contact assembly for the fuse device shown in Figure 1;

Figure 4 is a view, in front elevation, of the contact assembly shown in Figure 3;

Figure 5 is a. view, partly in side elevation and partly in section, of the upper contact assem-A bly for the fuse device shown in Figure 1;

Figure 6 is a view, in bottom plan, of the contact assembly shown in Figure 5;

Figures '7A and 7B, taken together, show the construction of the dropout fuse tube and associated parts, certain portions being broken away in order to more clearly illustrate the details of construction;

Figure 8 is a detail sectional view of the lower end of the fuse tube shown in Figures 7A and 7B in order to illustrate more clearly the construction of the clamping mechanism for the fuse cartridge shown in Figure 10, the fuse cartridge being shown in the latched position;

Figure'9 is a view similar to Figure 8 but showing the fuse cartridge inthe unlatched position;

Figure 10 is a longitudinal sectional view of a replaceable fuse cartridge or fuse link that is employed in the fuse tube shownl in Figures 7A and 7B; and

Figure 11 is a view showing an alternate form of terminal construction for the fuse cartridge shown in Figure 10.

Referring now particularly to Figures 1 and 2 of the drawings, it will be observed that the reference character II designates, generally, a dropout expulsion type fuse having a channel base I2 on which are mounted insulators I3 and I4. Upper and lower contact assemblies I5 and I6 are mounted on the insulators I3 and Il and they are provided, respectively, `with circuit terminal members I1 and I3 to permit clamping thereto of the line conductors. A fuse tube, shown generally at 20, is provided with upper and lower terminal assemblies 2l and 22. The upper terminal assembly 2I is arranged to have contact engagement with the upper stationary contact assembly I5 While the lower terminal `assembly 22 is arranged not only to have contact engagement with the lower contact assembly I6 but is also hingedly mounted thereon. When a fuse link or fuse cartridge within the fuse tube blows, as will be describedY hereinafter, the upper terminal assembly 2| is no longer held in the position shown in Figures 1 and 2 of the drawings but is released therefrom to permit the fuse 20 to rotate to the alternate position shown by the broken lines. This provides an air gap'between the circuit terminals formed by the contact assemblies I5 and I6 in addition to that which is provided by blowing of the fuse link or fuse cartridge itself.

In Figures 5 and 6 oi! the drawings the details of construction of the upper contact assembly I5 are more clearly shown. The upper contact assembly I5 is provided with a frame member 25 that is arranged to be suitably mounted on the insulator I3. It has integrally formed therewith-a sleet hood 25 which serves to protect the mechanism underneath including the upper terminal assembly 2I of the fuse tube 20 from the elements. Guide clips 21 are secured, as illustrated, to the opposite side walls of the sleet hood 28 for guiding the fuse tube 2l to the circuit closed position.

Flexible and resilient contact fingers 23 are provided with out and upwardly turned end portions 23 for contact engagement with the spaced apart contact surfaces on contact bosses 35, Figure 7A, forming a part of the upper terminal of the fuse tube 20. As will hereinafter appear, a portion of this upper terminal assembly 2| moves upwardly when the device is called upon to interrupt the circuit and, therefore, the outer ends 29 of the contact fingers 23 and the contact surfaces of the contact bosses 3|! are shaped as described to facilitate this movement. At their inner ends the contact lingers 23 are secured,

as by rivets, 3I, to the depending sides 32 oi' a backing member, shown generally at 33. A hinge pin 34 extending through the depending sides 32 of the backing member 33 and into the depending side Walls of the sleet hood 28 serves to rockably mount the backing member 33 and the parts carried thereby. A limited degree of freedom oi vertical movement in the contact nngers 28 is thereby provided which is not present in the construction referred to hereinbefore in the copending application of Ramsey in which the contact flngers are secured directly to the depending walls of the sleet hood. It will be observed that the outer end portions 35 of the sides 32 of the backing member 33 are turned outwardly and upwardly to correspond to the outer end portions 29 of the contact iingers 28. Coil compression springs 38 arev provided therebetween for, biasing the end portions 23 into contact engagement with the contact surfaces of the contact bosses 30, Figure 7A, of the upper terminal assembly 2l.

It will now be apparent that the contact iingers 2B have two degrees of freedom. Because of their being rockably mounted on the pin 3l, they are movable in a vertical plane. The inherent resiliency of the contact fingers 23 and the springs 36 permitrnovement in a horizontal plane. As a result close alignment is not required to be maintained between the fuse tube 20 or its mounting in the lower contact assembly I6 and the upper contact assembly I5. This is of considerable advantage not only from a manufacturing but also from an operating standpoint. It is not necessary to provide for mounting the lower terminal assembly 22 of the fuse tube 20 in the lower contact assembly I5 with close tolerances. In the field it is unnecessary to hold the insulators I3 and Il within close limits of tolerance nor must a great deal o! care be exercised in operatingthe fuse tube 23 to the circuit closed position. When it is recalled that fuse devices of the type disclosed herein are mounted overhead and are intended to be operated by means of switch hooks from a considerable distance, the advantages oi these features will be readily apparent.

It is desirable to automatically align the contact fingers 23 with the contact bosses 30, Figure 7A. For this purpose a centering arm 33 is integrally formed with one of the sides 32 of the backing member 33 and is provided with a slotted opening 40, the outer ends of which are flared outwardly, as illustrated in Figure 5, for receiving a guide pin 4|, Figure 7A, that is carried by a guide arm 42 forming a part of the upper terminal assembly 2| of the fuse tube 20. When the fuse tube 20 is operated toward the closed circuit position, the guide pin 4| first enters the flared out end portion of the slot 40 and then enters the slot 40 itself to lift the backing member 33 to the extent that may possibly be required. Since there is a definite relationship between the positions of the guide pin 4| and the contact bosses 30 and also between the slot 40 and the contact fingers 28, it will be readily apparent that proper contact engagement will be made between the outer end portions 29 of the contact fingers 28 and the contact surfaces of the contact bosses 30 despite the fact that they might otherwise be considerably out of alignment.

With a view to holding the fuse tube 20 in the circuit clo'sed position, a latch arm 43 is provided, Figure. 5, that is secured at its rearend by rivets v44 to a. bridging member 45 between the sides 32 of the backing member 33. The forward end of the latch arm 43 is split and the two portions thereof are turned at right angles t the remainder of the latch arm 43 as indicated at 46 for receiving therebetween a roller 41. A spring strip 48, secured in position by the rivets 44 which also hold the latch arm 43, serves to bias the roller 41 upwardly, its upward movement being limited by a stop 49 formed by a depending flange of the backing member 33. It will be understood that the roller 41 is adapted to be engaged by a latch hook 50, Figure 7A, forming a part of the upper terminal assembly 2| of the fuse tube 20. Since the latch arm 43 and the roller 41 carried thereby move with the backing member 33, the roller 41 is automatically centered with the latch hook 50 when the guide pin 4| enters the slot 40 in the centering arm 39.

In order to provide a good electrical connection between the backing member 33 and the frame 25 a flexible shunt 5| is provided comprising several layers of flexible copper strips. The flexible shunt is secured at one end by rivets 52 to a bridging member 53 between the sides 32 of the backing member 33. At its other end it is secured to the frame 25 by rivets 54.

The downward movement of the backing member 33 and the parts carried thereby about the hinge pin 34 is limited by a stop 55. It will be noted that the stop 55 is provided by a lug that may be cast integrally with one of the side walls of the sleet hood 2B.

In Figures 3 and 4 of the drawings the details of construction of the lower contact and hinge assembly I6 are illustrated. 'I'he assembly comprises a housing 60 that is open at the front and has a wall 6| closing the top and side walls 62 depending therefrom. A rear wall 63 joins Vthe walls 60 and 62, as shown. The assembly I6 serves not only to rockably mount the fuse tube 20 but also to conduct current to the lower terminal assembly 22.

In order to rockably mount the fuse tube 20, the side walls 62 are provided with slotted openings 64 for receiving therein trunnions, one of which is shown at 65 in Figure 7B of the drawings as forming a part of the lower terminal assembly 22. When the fuse link or cartridge within the fuse tube 20 blows, the fuse tube 20 is unlatched at its upper end, as previously described, and rotates dcwnwardly with the trunnions 65 turning in the bottoms of the slots 64. A rubber bumper 66 is provided for cushioning the inward swing ofthe fuse tube 28. Disengagement between the fuse tube 2U and the hinge and contact assembly i6 is prevented by interfittlng flanges 61 and 68. 'I'he flanges 61 are formed integrally with the side walls 62 and project inwardiy therefrom while the flanges 69, one of which is shown in Figure 7B, are integrally formed with the lower terminal assembly 22. it will be understood that, when the fuse tube 2U is in the circuit-closed position, the flanges 61 and 68 overlap, thereby preventing the recoil resulting from the blowing of the fuse link or cartridge causing the fuse tube 20 to move upwardly and possibly carry the trunnlons 65 out of the slots 64. It is only when the fuse tube 20 has rotated to the broken line position shown in Figure 1 that it is possible to lift it out of the slots 64. Likewise, it can only be inserted therein by being initially placed substantially in this position.

Contact engagement with the lower terminal assembly 22 is provided by an inverted U-shaped contact finger 69 that may be secured by rivets to the rear wall 63 of the housing 60, which pass through one leg thereof. As shown, the outer end of the other leg of the U-shaped contact finger 69 is turned back on itself as indicated at 1| to provide a curved surface for contact engagement with a contact shoe 12, Figure 7B, that is part of a contact arm 13 which extends from the lower terminal assembly 22 into the housing 60 when the fuse tube 20 is in the circuit closed position. An inverted U-shaped spring strip 14, conforming generally to the shape of the contact finger 69 and having one leg com- -monly secured to the rear wall 63 therewith by the rivets 10, is provided for biasing the other leg of the contact finger 69 outwardly into contact engagement with the contact shoe 12. While the contact finger 69 itself is resilient, the added resiliency of the spring strip 14 serves to bias the portion 1| into high pressure contact engagement with the contact shoe 12.

While it is desirable to bias the Contact finger 69 into high pressure contact engagement with the contact shoe 12, it is desirable that there be little movement of the turned back portion 1| required for effecting this high pressure contact engagement. Therefore, a pin 16 is provided through the turned back portion 1| its ends being secured in the side walls 62. The contact finger 69 and the spring strip 14 are then held in a prestressed condition when the contact shoe 12 is out of engagement therewith. In order to obtain the full biasing effect of the contact finger 69 and of the spring strip 14, it is only necessary for the contact shoe 12 to move the turned back portion 1| out of engagement with the pin 16. Despite the fact that only a slight movement of the contact finger 69 takes place, yet, as soon as it is moved away from the pin 16, the full biasing force of the contact finger 69 and of the spring strip 14 is available for providing the desired high pressure contact engagement. With a view to increasing the flexibility of the contact nger 69 and of the spring strip 14 they are split as indicated at 11 in Figure 4 of the drawings.

In Figures '7A and 7B of the drawings the details of construction of the fuse tube 2D are shown. It will be observed that it comprises an outer sleeve 80 and a lining or inner sleeve 8|. Preferably, the outer sleeve 80 is formed of a weather resisting material, such as phenolic condensation product, while the liner or inner sleeve 8| is formed of fiber for reasons now well known to those skilled in the art. If desired, the liner or inner sleeve 9| may be omitted and the outer sleeve 88 alone used. A replaceable fuse cartridge, shown generally at 82, and described in detail hereinafter, is provided at the lower end of the fuse tube 28 and connection thereto is provided by a exible cable 83. A coil tension spring 84 is provided for. tensioning the fuse cartridge 82 and withdrawing-a terminal therefrom as will presently appear.

At their upper ends the ilexible cable 83 and lthe spring 88 are secured to a cable and spring fastener having a ilanged head 85, the under surface of which engages a flange 88 of a sleeve 81 that is slidably mounted on a ferruie 88. A cap 89 is threaded on the sleeve, as shown, for clamping the flanged head 85 to the sleeve 81 for securing good electrical contact engagement therebetween. A spring 98, around the upper end of the fuse tube 28 and interposed between the sleeve 81 and the ferrule 88 serves to bias the former upwardly.

It will be noted that the contact bosses 38 and the latch hook 58 are formed integrally with the sleeve 81. As long as the fuse cartridge 82 remains intact, the sleeve 81 is prevented from moving upwardly under the influence of the coil spring 98. However, as soon as the fuse cartridge 82 blows, the sleeve 81 is no longer restrained but moves upwardly carrying with it the latch hook 58. As previously described, when it moves out o! engagement with the roller 41,

' Figure 6, the fuse tu-be 28 is then free to swing downwardly to the circuit open position. The upward movement of the sleeve 81 relative to the ferrule 88 is limited by screws 9| which project into suitable slots, not shown, in the ferrule 88.' The ferrule 88 is fastened on to the upper end of the fuse tube 28 so that it is rigid therewith. For this purpose transverse pins, one of which is shown at 94, are provided on opposite sides. Thus the guide arm d2, which is integrally formed with the ferrule 88, and the guide pin 4l are rigid with the fuse tube 28'.

In order to lift the latch hook 58 from engagement with the roller 41 for the purpose of manually removing the fuse tube 28, a pair of arms are provided, one of which is shown at 95, on opposite sides of the ferrule 88 as a part of an operating lever 96 which is pivoted on a pin 91 that extends through a portion of the ferrule 88, as shown. An eye 98 is formed integrally with the operating arm 9B and is adapted to be en gaged by the prong of a switch hook, as will be readily understood. A stop 99, forming a part of the eye 98, on engaging a flange |88 extending from the sleeve 81, serves to prevent upward movement of the latter when the fuse tube 28 is moved to the closed circuit position.

In Figures 1B and 8 the details of construction of the lower terminal assembly 22 are more clearly illustrated. This terminal assembly includes a ferrule |83 that is fixedly secured to the lower end of the fuse tube 28 by transversely extending pins, such as the pin |84 located near the top and on opposite sides. An eye |85 is integrally formed with the ferrule |83 to receive the prong of a switch hook for placing the fuse 28 in position with the trunnions 65 in the slots 64. It will be understood that the fuse tube is iirst positioned as shown by the broken lines in Figure l. The prong of the switch stick is then removed from 82. As illustrated in Figure 10, the sleeve |89 is of-substantial thickness and the peripheral groove |88 is formed adjacent its lower end. Preferably the sleeve |89 is formed of a phenolic condensa tion product. If desired, the sleeve |89 may be provided with a ber lining. Its lower end I8 is tapered in order to facilitate insertion through the garter spring |81. When the fuse cartridge 82 is positioned in the fuse tube 28, as shown in Figure 8 of the drawings, it is latched in position by the garterspring |81 interfltting in the peripheral groove |88 and reacting against the inclined surface |86. l

Withl a view to returning the garter spring |81 in operative position when the cartridge 82 is .not in position and at the same time permitting expansion of the garter spring |81 to receive the fuse cartridge 82, a sleeve I I is slidably mounted in the lower enlarged opening in the ferrule |83 below the inclined surface |88. The sleeve as shown, is provided with an linwardly extending flange i2 that bears against the underside of the garter spring |81.

A coil spring i I3 reacting between the underside of the flange |2 and the upper surface of a closure ring H4 serves to bias the sleeve Il upwardly. Radially extending pins H5, Figure 7B, serve to hold the closure ring I i4 in position in the lower end of the ferrule |83.

When the fuse cartridge 82 is drawn through the ferrule |83, the tapered end portion ||8 first engages the garter spring |81 and causes it to expand radially, Because of the inclined surface |86, it moves downwardly at the same timeand carries with it the sleeve Hi, at the same time compressing the spring H3. Since the convolutions of the garter spring |81 are spaced substantially uniformly about the sleeve |89 ot the fuse cartridge 82 and further since they bear uniformly against the upper surface of the flange H2, there is no likelihood of the latching mechanism binding at any point and preventing proper operation. It will be understood that the fuse cartridge 82 is drawn through the ferrule |83 until it reaches a position where the garter spring |81 can snap into the peripheral groove |88 in the sleeve |89. This it does by virtue of its own resiliency and also under the biasing influence of the coil spring H3 which tends to move the garter spring |81 upwardly, this upward movement having a radial complement because of the inclined surface |86.

At its lower end the fuse cartridge 82 is provided with a relatively iniusible metal terminal H8 that has an initially tubular shaped lower end portion ||9 which is collapsed, as shown, on to the two ends of a length of ilexible cable |28. After the fuse cartridge 82 has been latched in position, as shown in Figure 8, the looped end of the flexible cable |28 is positioned over the threaded stud l2l extending from the ferrule |83 and is clamped in position by the knurled nut |22. Since the sleeve |09 of the fuse cartridge 82 is latched in position by the garter spring |01, as previously described, the coil tension spring 84 does not apply any tension stress to the flexible cable |20. This simplifies the installation of the fuse cartridge 82 since it is unnecessary to hold the flexible cable against the tension force of the spring 84 and at the same time clamp it in position. Further, since the 4flexible cable |20 is comparatively slack inthe installed position, the terminal ||8 does not have applied to it any oblique stresses. It then remains centered with respect to the sleeve |09 of the fuse cartridge 82. At the same time the connection to the flexible cable |20 is positioned entirely away from the lower end of the sleeve |09 and out of the path of the products of the arc that are formed when the fusible element blows.

In order to remove the fuse cartridge 82 from its latched position in the lower ferrule |03, a release ring |24 is slidably and rotatably mounted in the ferrule |03, as illustrated. 'I'he release ring |24 is provided with a flanged head |25 and is biased upwardly by means of a coil compression spring |26 that reacts between the undersurface of the flanged head and the upper surfacel21 of a shoulder formed in the sleeve |03. The lower end of the release ring |24 is arranged to engage the garter spring |01, as will presently appear, and is normally held out of engagement therewith by the spring |26. A release operating ring |28 is provided externally of the lower ferrule |03 and is adapted to be grasped by the hand of the lineman. 'I'he release operating ring |28is both slidably and rotatably mounted exteriorly of the lower ferrule |03. Radial pins |29, extending through helical slots |30 in the wall of the ferrule |03 serve to mechanically interconnect the release ring |24 with the release operating ring |28. On rotation of the release operating ring |28 in the direction indicated by the arrow |3|, Figure 7B, it will be understood that the relase ring |24 is rotated therewith. At the'same time, because of the interaction between the pins -|29 and the helical slots |30, both of these rings are moved downwardly, compressing the spring |26. The lower end of the release ring |24 engages the garter spring |01 and moves it out of the peripheral groove |08 as is illustrated more clearly in Figure 9 of the drawings. The fuse cartridge 82 is then withdrawn by the spring 84, if the fuse cartridge is still intact, or, if it has blown, it will drop out of position when the fuse tube 20 is inverted. On release of the release operating ring |28 by the operator, it snaps back into the position shown in Figure 8 ofthe drawings.

If desired, one end of the spring |26 may be fastened to the under surface of the flanged head |25 and the other end may be fastened into the shoulder against whose surface |21 it reacts. This arrangement not only serves to bias the rings |25 and |28 upwardly but also biases them for rotation back to the normal position.

In Figure l0 of the drawings the details of construction of the refill unit or fuse cartridge 82 are more clearly shown. As previously described, the cartridge 82 is provided with a sleeve |09 having the peripheral groove |08 for interfitting with the garter spring |01. The sleeve |09 has a lining |35 formed by a filling of arc extinguishing material, such as boric acid. The filling of arc extinguishing material may either be continuous or in sections, as illustrated. The filling of arc extinguishing material |35 is provided with a central bore |36 of uniform diameter through which a rod-like terminal 31 may be withdrawn. At its upper end the rod-like terminal |31 is threaded, as indicated at |38, for engagement with a spring and cable fastener |39, Figure 7B, to which the lower ends of the flexible cable 83 and the tension spring 84 are also connected. 'I'he upper end of the sleeve |09 is transversely slotted, as shown at |40, for receiving the ends of a transverse pin |4| that extends through the rod-like terminal |31. This arrangement prevents rotation of the terminal rod |31 relative to the sleeve 09.

Initially the lower end of the terminal rod |31 is provided with an axially extending recess that is collapsed, as shown at |42, on to the ends of fusible and strain elements |43 and |44, respectively. 'I'he other ends of the fusible and strain elements have collapsed thereon the end portion |45 of the terminal ||8. As indicated at |48 and |41, the terminal end portions |42 and |45 are provided with prick punch marks for further deforming the metal thereof about the ends of the fusible and strain elements |43 and |44.

A fiber retaining ring |48 is provided at the lower end of the sleeve |09 and is secured thereto by transverse pins |49, as shown, The retaining ring |48 is flared outwardly to form an ring|48 is preferably formed of ber in order arcing chamber. As indicated, the retaining ring |48 is preferably formed of ber in order to withstand the heat that may be radiated from the fusible element 43 under normal operating conditions.

The lower end of the retaining ring |48 is slotted as indicated at |50 for receiving the ends of a pin |5| that extends transversely through the terminal ||8. The terminal ||8 is, therefore, prevented from rotating relative to the sleeve |09. It is then possible to grasp the fuse cartridge 82 at the terminal ||8 and thread it into the spring and cable holder |39, Figure 7B, without twisting the fusible ory strain elements |43 and |44. This is important, as will be readily understood, since such twisting action might injure or even break one or `both of these elements or might alter the time-current characteristics thereof.

The sleeve |09 is lled with as many sections of the arc extinguishing material |35 as is desired. One or more spacers |52 are then inserted at the upper end to ll the remaining o space underneath a retaining ring |53 which is held in position by transverse pins |54, as shown.

For` installation purposes, a pull-up cord |55 is looped about the flexible cable |20 and is provided at its end with a suitable Weight |56. It will be understood that the pull-up cord |55 is removed once the fuse 'cartridge 82 has been installed.

Under predetermined overload conditions the fusible and strain elements |43 and |44 will be fused and an arc will be formed between the terminal ||8 andthe rod-like terminal 31. Since the rod-like terminal |31 is no longer restrained, it will move upwardly through the bore |36 in the filling of arc extinguishing material |35 under the influence of the tension spring 84. The heat of the arc will cause water vapor to be evolved from the wall of the bore |38 which forms a highly efficient arc extinguishing medium. The terminal ||8 will be blown out of the lower end of the fuse cartridge 82 but is prevented from falling by the flexible cable |20. The lower end of the sleeve |09 and the retaining ring |48 is open, however, to permit free egress of the products of the arc. Since the sleeve |09 is held latched to the lower ferrule |08 by the garter spring |01, the filling of arc extinguishing material |35 is held stationary while the rod-like terminal |31 is moved upwardly therethrough. The length of the rod-like terminal |31 is such that it is not withdrawn from the bore |36 when the tension spring 84 is fully collapsed.

As previously described, when the fuse cartridge 82 blows, the sleeve 81 of the upper terminal assembly 2| is no longer restrained. It then moves upwardly under the influence of the spring 80 to lift the latch hook 50 ofi of the roller 41 to permit the fuse tube 20 to swing downwardly to the broken line position shown in Figure 1 of the drawings. The movement 'of the fuse tube 20 to the open circuit position not only provides an air gap in the circuit in addition to that provided by the blowing of the fusible and strain elements |43 and |44 but it also serves to indicate that the circuit has been interrupted and that the cartridge 82 should be replaced by a new one.

Accordingly, the lineman inserts the prong of his hook stick in the eye |05 and removes the fuse tube 20 fromthe lower contact assembly I8, Figure 1. He then removes the cap 89, Figure 7A, and withdraws the spring and cable assembly including the flexible cable 83 and the spring 84, also carrying with it the rod-like tex'- minal |31. He then inverts the fuse tube 20 and rotates the release operating ring |28 in the direction indicated by the arrow |3I, Figure 7B, and the remaining portions of the fuse cartridge 82 drop out. The knurled nut |22 is then loosened and the flexible cable |20 is removed.

After unscrewing the rod-like terminal |31 from the spring and cable fastener |39, a new fuse cartridge 82 is screwed into place. The pull-up cordl with the weight |58 are then attached to the flexible cable loop |20 and the entire assembly is dropped through the fuse tube 20 from the upper end and the cap 89 is replaced. The weight |58 carries the pull-up cord |55 out of the lower end of the fuse tube 20 where it can be grasped by the hand of the lineman. He then pulls it through the fuse tube 20 until the cartridge 82 is moved to such position that the garter spring engages the peripheral groove |08 to latch the same in position. He then removes the pull-up cord |55 and clamps the end of the flexible cable loop |20 in position by the knurled nut |22. The fuse tube 20 is now ready to be connected in the circuit, as previously described.

As shown in Figure 11 of the drawings, the flexible lead |20 may be provided With a lug or terminal 60 to facilitate attachment to the lower ferrule |03 on being placed over the stud |2| and clamped in position by the nut 22. The lug or terminal |60 may comprise a metal sleeve flattened onto the looped lower end of the ilexible lead |20.

In the copending application of Ramsey, referred to hereinbefore, three fuse tubes are provided which are arranged to be repeatedly connected into the circuit. That is, on the blowing of the fuse tube that is connected in the circuit, it drops out, as described, and in so doing closes a transfer switch which connects the next fuse tube into the circuit.

When the second fuse blows, it drops out and operates a transfer switch to connect the last fuse tube into the circuit. When the last fuse tube drops out, the circuit is not again reclosed.

It will be understood that the present invention may be employed in connection with a repeating fuse structure, as disclosed in this copending application of Ramsey, merely by the provision of two or more units with transfer switches arranged as required for completing the circuit through the next fuse when the preceding fuse blows.

Since certain further changes may be made in the foregoing construction and different embodiments o! the invention may be made without departing from the scope thereof, it is intended that all matter shown in the accompanying drawings or described hereinbefore shall be interpreted as illustrative and not in a limiting sense.`

I claim as my invention:

1. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, a replaceable circuit interrupting device insertable through one end of said housing and including a fuse cartridge attached to a spring having means at its free end cooperating with said one end of said housing for holding the same thereat, means at the other end of said housing automatically intertting with said fuse cartridge when it is drawn to a predetermined position through said housing for latchlng the same thereat, and manually operable means shiftable through a relatively short arc for releasing said automatic interlocking means.

2. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, a replaceable circuit interrupting device insertable through one end of said housing, means automatically interlocking with said replaceable circuit interrupting device at the other end of -said housing on its being moved to a predetermined position in said housing for holding the same thereat, and means located at said other end of said housing and manually shiftable through a relatively short arc for releasing the automatic interlocking means to permit removal of said replaceable circuit interrupting device.

3. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, a replaceable circuit interrupting device insertable through one end of said housing and including a fuse cartridge attached to a spring having means at its free end cooperating with said one end of said housing for holding the same thereat, means at the other 'end of said housing automatically intertting with said fuse cartridge when it is drawn to a predetermined position through said housing for latching the same thereat, and means adapted to be manually shifted through a relatively short arc for releasing the automatic latching means to permit removal of said fuse cartridge from said housing.

4. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, tubular terminals at the ends of said housing, a replaceable circuit interrupting device insertable through one ofl said tubular terminals including a fuse cartridge attached to a tension spring having means at its free end cooperating with said one terminal for holding it thereat, and means carried by the other tubular terminal on the portion thereof adjacent said housing for automatically interlocking with said fuse cartridge when sit is drawn therepast to hold the same in a predetermined position in said housing.

5. A renewable' circuit interrupter comprising, in combination, a tubular insulating housing, tubular terminals at the ends of said housing, a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge attached to a tension spring having means at its free end cooperating with said one terminal for holding it thereat, means carried by the other tubular terminal for automatically interlocking with said fuse cartridge when it is drawn therepast to hold the same in a predetermined position in said housing, and manually operable rotatable means disposed externally of said other tubular terminal on the end thereof adjacent said housing'for releasing the automatic interlocking'means to permit removal of said fuse cartridge from said housing.

6. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, a replaceable circuit interrupting device insertable through one end of said housing, means automatically interlocking with said replaceable circuit interrupting device at the other end of said housing on its being moved to a predetermined position in said housing for holding the same thereat, and a flexible lead forming part of said replaceable circuit interrupting device and extending outside of said other end of said housing to permit external connection thereto.

7. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, a replaceable circuit interrupting device insertable through one end of said housing and including a fuse cartridge attached to a spring having means at its free end cooperating with said one end of said housing for holding the same thereaty means at the other end of said housing automatically intertting with said fuse cartridge when it is drawn to a predetermined position through said housing for latching the same thereat, means adapted to be manually operated for releasing the automatic latching means to permit removal of said fuse cartridge from said housing, and a flexible lead connected to said fuse cartridge and extending outside of said other end of said housing to permit external connection thereto, said flexible lead being unstressed by said spring when said fuse cartridge is latched in operative position.

8. A renewable circuit interrupter comprising, in combination, a tubular insulating housing, tubular terminals 'at the ends of said housing, a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge attached to a tension spring having means at its free end cooperating with said one terminal for holding it thereat, meansv carried by the other tubular terminal for automatically interlocking with said fuse cartridge when it is drawn therepast to hold the same in a predetermined position in said housing, and a flexible lead interconnecting said fuse cartridge and said other tubular terminal, said flexible lead being unstressed by said tension spring when said fuse cartridge is latched in operative position.

9. A renewable circuit interrupter comprasing, in combination, a tubular-insulating horsing, tubular terminals at the ends of said hcusing, a replaceable circuit interxupting device insertable through one of said tubular terminals including a fuse cartridge attached to a tension spring having means at its free end cooperating with said one terminal for holding it thereat, means carried by the other tubular1 terminal for automatically interlocking with said fuse cartridge when it is drawn therepast to hold the same in a predetermined position in said housing, manually operable means disposed externally of said other tubular terminal for releasing the automatic interlocking means to permit removal of said fuse cartridge from said housing, clamp means carried by said other tubular terminal, and a flexible lead extending from said fuse cartridge and secured to said other tubular terminal by said clamp means, said flexible lead being unstressed by said tension spring when said fuse cartridge is latched in operative position.

10. A renewable circuit interrupter comprising, in combination; a tubular insulating housing; tubular terminals at the ends of said housing; a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge, a tension spring connected to said fuse cartridge at one end of said sleeve, and means at the free end of said spring cooperating with said one tubular terminal for holding it thereat, and means carried by the other tubular terminal for automatically interlocking with said sleeve of insulating material when said fuse cartridge is drawn to a predetermined position in said housing.

11. A renewable circuit interrupter comprising, in combination; a tubular insulating housing; tubular terminals at the ends of said housing; a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge, a tension spring connected to said fuse cartridge at one end of said sleeve, means at the free end of said spring cooperating with said one tubular terminal for holding it thereat, and a flexible lead connected to said fuse cartridge and extending from the other end of said sleeve, means carried by the other tubular terminal for automatically interlocking with said sleeve of insulating material when said fuse cartridge is termined position in said housing; and means carried by said other tubular terminal for receiving said flexible lead for connection thereto, said flexible lead being unstressed by said tension spring.

12. A renewable circuit interrupter comprising, in combination; a tubular insulating housing; tubular terminals at the ends of said housing; a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge, a tension spring connected to said fuse cartridge at one end of said sleeve, and means at the free end of said spring cooperating with said one tubular terminal for holding it thereat; means carried by the other tubular terminal for automatically interlock'ng with said sleeve of insulating material when said fuse cartridge is drawn to a predetermined position in said housing; and manually operable means operatively interconnecting said other tubular terminal and said automatic interlocking means for releasing the latter from said sleeve by rotation of the manual means relative to the other tubular terminal.

13. A renewable circuit interrupter comprising, in combination; a tubular insulating housing; tubular terminals at the ends of said housing, a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge, a tension spring connected to said fuse cartridge at one end of said sleeve, means at the free end of said spring cooperating with said one tubular terminal for holding it thereat, and a flexible lead connected to said fuse cartridge and extending from the other end of said sleeve; means carried by the other tubular terminal for automatically interlocking with said sleeve of insulating material when said fuse cartridge is drawn to a predetermined position in said housing; and manually operable means operatively interconnecting said other tubular terminal and said automatic interlocking means for releasing the latter from said sleeve by rotation of the manual means relative to the other tubular terminal.

14. A renewable circuit interrupter comprising, in combination; a tubular insulating housing; tubular terminals at the ends of said housing; a replaceable circuit interrupting device insertable through one oi said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge having' an external peripheral groove adjacent one end, a tension spring connected to said fuse cartridge at the other end of said sleeve, means at the free end of said spring cooperatingv with said one tubular terminal for holding it thereat, and a iiexible lead connected to said fuse cartridge and extending from said one end of said sleeve; means interacting between said other tubular terminal and said peripheral groove in said sleeve for automatically latching said fuse cartridge in a predetermined position in said housing when it is drawn thereto; and means carried by said other tubular terminal for receiving said ilexible lead for connection thereto, said flexible lead being unstressed by said tension spring.

15. A renewable circuit interrupter comprisling, in combination; a tubular insulating housing; tubular terminals at the ends of said housing; a replaceable circuit interrupting device insertable through one of said tubular terminals including a fuse cartridge, a sleeve of insulating material for said fuse cartridge having an external peripheral groove ladjacent one end, a tension spring connected to said fuse cartridge at the other end of said sleeve, means at the free end of said spring cooperating with said one tubular terminal for holding it thereat, and a ilexible lead connected to said fuse cartridge and extending from said one end of said sleeve; means interacting between said other tubular terminal and said peripheral groove in said sleeve for automatically latching said fuse cartridge in a predetermined position in said housing when it is drawn thereto; means carried by said other tubular terminal for receiving said flexible lead for connection thereto, said iiexible lead being unstressed by said tension spring; and manually operable means operatively interconnecting said other tubular terminal and said automatic interlocking means for releasing the latter from the groove in said sleeve by rotation of the manual means relative to the other tubular terminal.

16. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove, of means for securing the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing, and resilient means disposed internally of said tubular terminal and adapted to interfit with said peripheral groove in said fuse cartridge.

17. 'I'he combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove,

of means for securing the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing, resilient means disposed internally of said tubular terminalI and adapted to interiit with said peripheral groove in said fuse cartridge, and externally operable manual release means carried by said tubular terminal for moving said resilient means out of said peripheral groove to permit removal of said fuse cartridge from said housing.

18. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove, of means for securing the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing, a garter spring inside said tubular terminal for interfltting with said peripheral groove in said fuse cartridge, and resilient means biasing said garter spring into operative position, said resilient means being arranged and adapted to `permit said garter spring to be expanded on insertion of said fuse cartridge into said tubular terminal.

19. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove, of means for securing the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing, a garter spring inside said tubular terminal for intertting with said peripheral groove in said fuse cartridge, resilient means biasing said garter spring into operative position, said resilient means being arranged and adapted to permit said garter spring to be expanded on insertion of said fuse cartridge into said tubular terminal, and externally operable manual release means carried by said tubular terminal for moving said garter spring out of said peripheral groove to permit removal of said fuse cartridge from said housing.

20. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove adjacent one end, of latch means for latching the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing having an inclined shoulder portion intermediateits ends, a garter spring interfltting between said peripheral groove and said inclined shoulder portion, and lost motion means cooperating with said garter spring for holding the same in operative position and permitting expansion thereof on insertion of said fuse cartridge.

21. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove adjacent one end, of latch means for latching the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing having an inclined shoulder portion intermediate its ends, a garter spring interfitting between said peripheral groove and said inclined shoulder portion, a sleeve member slidable in said tubular terminal and having a shoulder portion engaging said garter spring; and spring means biasing said sleeve member toward said garter spring for holding the same in operative position and permitting expansion thereof on insertion of said fuse cartridge,

22. The combination, with'a tubular insulatving housing and a renewable fuse cartridge therefor having an external peripheral groove adjacent one end, of latch means for latching the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing having an inclined shoulder portion intermediate its ends, a garter spring interfitting between said peripheral groove and said inclined shoulder portion, lost motion means cooperating with said garter spring for holding the same in operative position and permitting expansion thereof on insertion of said fuse cartridge, a release ring slidable and rotatable in said tubular terminal for operatively engaging said garter spring, spring means biasing said release ring away from said garter spring, a release operating` ring manually rotatable externally of and slidable with respect to said tubular terminal, said tubular terminal having helical grooves coextensive withl said release operating ring, and pin means operatively interconnecting said release and operating rings through said helical grooves in such manner that rotation of said operating ring causes said release ring to engage said garter spring and move the same out of said peripheral groove to permit removal of said fuse cartridge from said housing.

23. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external peripheral groove adjacent one end, of latch means for latching the fuse cartridge in a predetermined position in said housing comprising, a tubular terminal at one end of said housing having an inclined shoulder portion intermediate its ends, a garter spring interfitting between said peripheral groove and said inclined shoulder portion, a sleeve member slidable in said tubular terminal and having a shoulder portion engaging said garter spring, spring means biasing said sleeve member toward said garter spring for holding the same in operative position and permitting expansion thereof on insertion of said fuse cartridge, a release ring slidable and rotatable in said tubular terminal for operatively engaging said garter spring, spring means biasing said release ring away from said garter spring, a release operating ring manually rotatable externally of and slidable with respect to said tubular terminal, said tubular terminal having helical grooves coextensive with said release operating ring, and pin means operatively interconnecting said release and operating rings through said helical grooves in such manner that rotation of said operating ring causes said release ring to engage said garter spring and move the same out of said peripheral groove to permit removal of said fuse cartridge fromsald housing.

24. A renewable cartridge comprising, in combination, a tubular insulating member, a lling of solid arc extinguishing material in said tubular member having a bore extending longitudinally therethrough, a. rod-like terminal substantially filling said bore and adapted to be withdrawn through one end thereof, a relatively infusible terminal at the other end of said bore, fusible means interconnecting said terminals, flexible lead means connected to the last named terminal to permit external connection thereto, and means carried by said cartridge for cooperating with latching means carried by a fuse tube for holding the cartridge in a predetermined position with re- 9 spect to said fuse tube independently of said flexible lead means.

25. A renewable cartridge comprising, in combination, a tubular insulating member, a iiliing of solid are extinguishing material in said tubular member having a bore extending longitudinally therethrough, a rod-like terminal substantially lling said bore and adapted to be withdrawn through one end thereof, a relatively infusible terminal at the other end of said bore, fusible means interconnecting said terminals, exible lead means connected to the last-named terminal to permit external connection thereto, and means preventing rotation of both said terminals relative -to said tubular insulating member.

26. A renewable cartridge comprising, in combination, a tubular insulating member having a peripheral groove adjacent one end for cooperating with automatic latching means in an expulsion fuse tube, a filling of solid arc extinguishing material in said tubular member having a bore extending longitudinally therethrough, a rod-like terminal substantially filling said bore and adapted to be withdrawn through one end thereof, a relatively infusible terminal at the other end of said bore, fusible means interconnecting said terminals, and flexible lead means connected to the last-named terminal to permit external connection thereto.

27. A high tension circuit interrupter for completing a circuit between a pair of circuit terminals comprising, in combination; a tubular fuse housing; a fuse tube terminal at the upper end of said fuse housing for contact engagement with one of said circuit terminals; means within said fuse housing for connecting said fuse tube terminal to the other oi' said circuit terminals including fusible means, a iilling of solid arc extinguishing material having a longitudinal bore of substantially uniform diameter and a rod-like terminal adapted to draw the arc formed on blowing of said fusiblemeans within said bore for extinguishing the same; and means for releasing said fuse tube terminal from its circuit terminal on blowing of said fusible means to interpose an air gap between said circuit terminals in addition to the gap formed by blowing o1' said fusible means.

28. A high tension circuit interrupter for completing a circuit between a pair oi' circuit terminals comprising, in combination; a tubular fuse housing; a fuse tube terminal at the upper end of said fuse housing for contact engagement with one of said circuit terminals; means within said fuse housing for connecting said fuse tube terminal to the other of said circuit terminals including fusible means, a filling of solid arc extinguishing material having a longitudinal bore of substantially uniform diameter and a rod-like terminal adapted to draw the arc formed on blowing oi' said fusible means within said bore for extinguishing the same; a flexible lead interconnecting said fusible means and the other circuit predetermined position therein for holding the same thereat, and externally manually operable release means at said other end of said housing adapted to be moved through a relatively short distance and to cooperate with said automatic interlocking means for releasing said device.

30. A renewable cartridge for an expulsion type fuse comprising, in combination, a tubular insulating member of uniform external diameter having a peripheral groovel adjacent one end for cooperating with automatic latching means in a fuse tube, a lling of solid arc extinguishing material in said tubular member having a bore extending longitudinally therethrough, a rod-like terminal substantially filling said bore and adapted to be Withdrawn through one end thereof, a relatively infusible terminal at the other end of said bore, and fusible means interconnecting said terminals.

31. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having an external circumferential groove, of means for securing the fuse cartridge in a pref` determined position in the housing comprising, a tubular terminal at one end of said housing, and spring biased means within said tubular terminal adapted to interiit with said groove of said fuse cartridge.

32. The combination, with a tubular insulating housing and a renewable fuse cartridge therefor having a circumferential groove, of means for securing the fuse cartridge in a predetermined position in the housing comprising, a tubular terminal at one end of said housing, spring biased means within said tubular terminal adapted to interiit with said groove of said fuse cartridge, and externally operable manual release means cooperating with said spring biased means for releasing the same from engagement with said fuse cartridge.

33. A circuit interrupter comprising, in combiy nation, a pair of line terminals and means for mounting the same in insulated spaced relation, a fuse tube having terminals at its ends for engaging said line terminals andl open at one end, latching means for releasably holding said fuse tube in operative position, a mass of solid arc extinguishing material adjacent said one end of said fuse tube having a bore extending longitudinally therethrough, and conductor means extending through said longitudinal bore for interconnecting said terminals on said fuse tube and controlling said latching means; said conductor means including a relatively infusible terminal .connected to the fuse tube terminal at said one end of said fuse tube, a rod-like terminal substantially filling said longitudinal bore and connected to the other fuse tube terminal, and fusible means interconnecting said infusible and rod-like terminals, said latching means being released on blowing of said fusible means whereupon said fuse tube moves from said operative position and an air gap is provided between at least one of said line terminals and its associated fuse tube terminal.

34. A circuit interrupter comprising, in combination, a pair of line terminals and means for mounting the same in insulated spaced relation, a fuse tube having terminals at its ends for engaging said line terminals and open at one end, latching means for releasably holding said fuse tube in operative position, a mass of solid arc extinguishing material adjacent said one end of said fuse tube having a bore extending longitudinally therethrough, conductor means extending through said longitudinal bore for interconnecting said terminals on said fuse tube and controlling said latching means; said conductor means including a. relatively inusible terminal connected to the fuse tube terminal at said one end of said tues tube, a rod-like terminal substantially filling said longitudinal bore and connected to the other fuse tube terminal, and fusible means interconnecting said iniusible and rodlike terminals, said latching means being released on blowing of said fusible means whereupon said fuse tube moves from said operative position and an air gap is provided between at least one of said line terminals and its associated fuse tube terminal, and spring means restrained by said fusible means and released on blowing thereof for effecting relative movement between said rod-like terminal and said longitudinal bore and operating said latching means to unlatching position.

35. Circuit interrupting apparatus comprising, in combination, solid arc extinguishing material having a bore from the inner wall of which a relatively large quantity of water vapor is evolved due to the heat of an arc, terminals adapted to be moved relatively apart and to draw an arc therebetween within said bore, one of said terminals being rod-like in character and disposed within said bore and movable relative thereto, and disconnecting means operable as a result of relative movement apart of said terminals for providing an air gap in the circuit in addition to the gap provided therein between said terminals after the arc is extinguished.

36. Circuit interrupting apparatus comprising, in combination, solid arc extinguishing material having a bore from the inner wall of which a relatively large quantity of water vapor is evolved due to the heat of an arc, terminals adapted to be moved relatively apart and to draw an arc therebetween within said bore, one of said terminals being rod-like in character and disposed within said bore and movable relative thereto, and means operable as a result of relative movement apart oi' said terminals for bodily moving said solid arc extinguishing material to an alter nate position to provide an air gap in the circuit in addition to the gap provided therein between a said terminals after the arc is extinguished.

37. Circuit interrupting apparatus comprising, in combination, solid arc extinguishing material having a bore from the inner wall of which a relatively large quantity of water vapor is evolved due to the heat of an arc, terminals adapted to be moved relatively apart and to draw an arc therebetween within said bore, one of said terminals being rod-like in character and disposed within said bore and movable relative thereto, spring means acting to bias said terminals apart, fusible means interconnecting said terminals and restraining movement thereof apart, and disconnecting means operable as a result of relative movement apart of said terminals for providing an air gap in the circuit in addition to the gap provided therein between said terminals after the arc is extinguished.

38. In a circuit interrupter, in combination, a fuse tube, a mass of solid arc extinguishing material adjacent one end of said fuse tube having a bore extending longitudinally therethrough, a relatively infusible terminal at said one end of said fuse tube, a rod-like terminal substantially filling said longitudinal bore, means biasing said rod-like terminal for movement relative to said bore, fusible means interconnecting said terminals and restraining said rod-like terminal from movement under the iniiuence of said biasing means, and a member connected to said rod-like terminal and movable endwise of said fuse tube externally thereof as a result of blowing of said fusible means.

39. A high tension circuit interrupter for completing a circuit between upper and lower circuit terminals comprising, in combination; a tubular fuse housing and means pivotally mounting the same relative to said lower circuit terminal, a fuse tube terminal at the upper end of said fuse housing for contact engagement with said upper circuit terminal; means within said fuse housing for connecting said fuse tube terminal to said lower line terminal including fusible means, a lling of solid arc extinguishing material having a longitudinal bore of substantially uniform diameter and a rod-like terminal adapted to draw the arc formed on blowing of said fusible means within said bore for extinguishing the same; latching means for maintaining said contact engagement between said fuse tube terminal and said upper circuit terminal and holding said fuse housing in operative position; and means for releasing said latching means on blowing of said fusible means whereby said fuse housing is permitting to swing to an inoperative position and an air gap is interposed between said fuse tube terminal and said upper circuit terminal.

HUGH A. TRIPLETT.

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