US2315678A - Circuit interrupter - Google Patents

Description

Patented Apr. 6, 1943 UNITED STATES PATENT QFFICE CIRCUIT INTERRUPTER Pennsylvania Application January 24, 1940, Serial No. 315,306

20 Claims.

This invention relates generally to circuit interrupters, and more particularly to interrupters of the type adapted to be automatically disconnected from their associated circuit in response to an interrupting operation.

Although my invention will be disclosed herein as embodied in a high voltage drop-out fuse wherein it has certain particular novel cooperation and utility, it should be understood at the outset that it is also applicable to other circuit interrupters of the type capable of automatically interrupting a circuit in response to the passage therethrough of currents greater than a predetermined value.

Circuit interrupters of the above type, and particularly high voltage fuses may be movably mounted adjacent one end thereof for movement into or out of engagement with respect to a resilient line contact, and a spring-biased latch may be provided to maintain the fuse in engagement with the resilient contact.

One object of my invention is to provide a circuit interrupter of the type described with novel means to enable the interrupter to automatically release itself from at least one of its associated line contacts in response to a circuit interrupting operation.

Another object of my invention is to provide an interrupter of the type described with novel means operable automatically in response to an interrupting operation for removing the support from a part of the interrupter which normally maintains the interrupter in its associated circuit.

Another object of my invention is to provide a circuit interrupter embodying relatively movable parts, together with novel means normally maintaining said parts in fixed relation.

A further object of my invention is to provide an interrupter enclosure of novel construction.

Still another object of my invention is to provide a high voltage fuse having embodied therewith novel means enabling the same to become released from its associated circuit so that it may drop-out to insert an air gap in the circuit.

Another object of my invention is to provide in a high voltage renewable fuse having an enclosure embodying relatively movable parts, nove1 means for normally maintaining said parts in substantially fixed relation, which means operate automatically to normal position incident to assembly of the fuse, and, in response to blowing of the fuse, permits relative movement of said parts.

Another object of my invention is to provide a novel high voltage fuse construction having a novel end cap construction which is relatively movable in response to blowing of said fuse.

These and other objects of my invention will become more apparent upon consideration of the following specification of preferred embodiments of my invention, taken in connection with the attached drawings, in which:

Figure 1 is a side elevational view showing a fuse constructed in accordance with my invention;

Fig. 2 is a longitudinal, sectional view of the fuse shown in Fig. l and showing a fragment of the top latch for the fuse;

Fig. 3 is a fragmentary, longitudinal, sectional view of the upper fuse terminal cap assembly taken at right angles to the section of Fig. 2;

Fig. 4 is a transverse, sectional view taken substantially on the line IV-IV of Fig. 3;

Fig. 5 is a perspective view of a supporting lever for the upper fuse terminal cap assembly;

Fig. 6 is a plan view of a supporting member in the fuse terminal cap assembly;

Fig. 7 is a front view of a slightly modified form of supporting element for the fuse terminal cap assembly;

Fig. 8 is a fragmentary, longitudinal, sectional view similar to Fig. 4 but showing a slightly modified form of construction;

Fig. 9 is a cross-sectional View of the upper fuse terminal cap assembly shown in Fig. 8 and taken substantially on the line IX--IX of Fig.

'8; and

Fig. 10 is a fragmentary, longitudinal, sectional view similar to Fig. 8 showing a further modified construction.

Referring to the drawings, I have shown in Fig. l, a channel supporting member 2 for supporting spaced upper and lower insulators 4 and 6, suitably secured thereto. The lower insulator 6 includes a metallic cap member 8 which may be of any suitable conducting material such as copper or the like. The insulator cap 8 has secured thereto a downwardly extending terminal portion ill for connection to a line conductor. Extending outwardly from the lower insulator cap 8 are spaced contact portions l2 adapted to pivotally support the lower end of a fuse H3. The fuse includes a lower terminal ferrule it having on opposite sides thereof outwardly projecting stop lugs I8 and trunnions 20, about which the fuse is adapted to pivot. Each contact leg 12 has its outer portion substantially U-shaped in form with a pair of indentations at each end of the bight portion thereof. The U-shaped outer portion of each contact leg I2 is provided with an upper arm 22 adapted to cooperate with the stop lug I8 and a lower guide arm 24- for guiding the trunnions into one of the indentations in the contact legs l2. A leaf spring member 25 is fixed to the lower cap 8 between the contact portions [2, by any suitable means such, for example, as by welding or the like, and has its upper end bent outwardly away from the insulator cap 8 to engage an upper portion of the fuse terminal ferrulelii, to normally urge the fuse in a clockwise direction about its trunnions From the foregoing, it is apparent that the fuse I4 is pivotally mounted on the lower contact arms !2 by the fuse trunnions 29, and when in a vertical position, as shown in Fig. 1, the fuse is urged by the spring 25 for pivotal'movement.

in a clockwise direction about its trunnions 20. It will be apparent that, if the fuse is moved in this direction, it will move until the stop lugs.

B engage with the outer end of the contact arms 24, to thereby stop such'movement of the fuse. In this position, the fuse may be lifted out from between the contact arms l2 for refusing-and thereafter may be inserted between the contact arms l2 and then pivotally moved in a counter clockwise direction to the position shown in Fig.

1. Obviously, if no means is provided'for maintaining the fuse in the position shown in Fig. 1, the fuse will necessarily move under the influence of spring 25 to the drop-out position in which its stop lugs l8 engage the contact arms 24.

The upper insulator 4 is also provided with a cap 26' similar to the cap 8 on the lower insulator,

and the cap 26 has secured thereto an upwardlyextending terminal portion 28 adapted to be con-' nected to a line conductor. Extending outwardly from the upper portion of the insulator cap 28 are a pair of pivot supporting arms 30 between which is pivotally mounted a latch 32, as by a pivot pin 34. A fixed stop -is provided slightlyspaced below the latch 32 and integral with the terminal portion 23 for limiting clockwise movement of the latch 32' about its pivot 34, for a purpose hereinafter to be described. A leaf spring 38 has I the inner end thereof fixed to the terminal portion 28 and the outer end thereof bearing upon latch 32 to normally urge the same downwardly into engagement with the fuse M, or with the stop 38 when the fuse is not in operative position. The outer end of the latch 32 is turned upwardly,

as shown at 4B, and is provided on its underside with a notch 42 for receiving a projection 44 on the top-of the upper fuse terminal cap assembly; 66, for maintaining the fuse in the position shown in Fig. l. The fuse terminal cap assembly 46 is provided with a pair of laterally extending spaced pivot supporting arms 43 for pivotally supporting a hook-eye operating member 5% which has an integral latch releasing extension 52 normally extending into proximity with the lower surface of the latch 32.

In the structure thus far described, it is apparent that, as shown in Fig. 1, the fuse I4 is latched in engagement with a pair of line contacts. The circuit through the fuse may be traced from the upper line terminal 28, latch 32, upper fuse terminal cap assembly 45, through the fuse to the lower terminal ferrule l6, contact spring 25. to the lower terminal lfl. To manually remove the fuse from the line contacts, it is mere- 13? necessary to insert a hook-stick or other operating member into the aperture in the hook-eye 5i] and exert a downward and outward pull on the same, to thereby rotate the hook-eye in a clockwise direction about its pivot, so that the extension 52 thereof engages the lower surface of the latch 32 to move the same upwardly out of engagement with the projection 44 on the upper terminal cap assembly, whereupon the fuse may be rotated in a clockwise direction about its trunnions, aided by the spring 25 on the lower terminal Hi, to the position wherein the fuse stop lugs l8 engage the contact arms 24. From this position, the fuse may be removed from the lower contact if desired. To re-insert the fuse in engagement with both line contacts, its trunnions 20 are first moved into engagement with the lowercontact arms I 2 and the fuse manually rotated ina counter-clockwise direction by means of the hook-eye 56, so that the projection 44 on the upper terminal fuse cap assembly engages the curved outer end 49 of the latch 32 to cam the latch upwardly, and permit the projection 44 to move under the latch to the position in which it registers with the notch 42, whereupon the latch falls downwardly into locking engagement with the projection 44 under influence of the leaf spring 38 aided by gravity.

The fuse proper includes an insulating fuse tube 54, which may be of fibre, porcelain, glass or the like, in the lower end of which is positioned a refill element which includes an outer insulating tube 56 of fibre, or the like, on the lower end of which is threadedly mounted a terminal ferrule 58 clamped in the lower fuse ferrule 16, as by the clamping ring 60, threadedly engaging the inner surface of the fuse ferrule HE. A liner 62 is provided in the refill fuse tube 58 of a material which is capable of evolving an arc extinguishing gas when in proximity to an electric arc. The liner 62 may be of boric acid, fibre, a synthetic resin, or the like. A fusible and strain means 64 is connected at one end, as by the screw 66, with the refill terminal ferrule 58, and is connected at its other end to an arcdrawing rod 68 positioned in the bore provided in the gas evolving material 62. The upper end of the are drawing rod 68 is detachably connected with a piston member 12 slidable in the fuse tube 54, and the piston is in turn connected to a conducting rod (4, conductively connected to the upper terminal cap assembly 46. The connection between the piston l2 and the conducting rod 14 is by way of flexible shunts l6 and further includes a coil tension spring 18 which, in the normal condition of the fuse, is maintained .inan extended position, as seen in Fig. 2. The particular construction of the refill element, including the structure of are drawing rod 68, plunger'l'l, shunts 16, and spring 18, and

the specific manner in which the refill is secured in the fuse tube and the specific construction of these parts is substantially the same as disclosed in the patent to H. L. Rawlins, No. 1,976,634, issued October 9, 1934, and the particular fusible and strain means is particularly disclosed and claimed in the patent to H. H. Fahnoe, 2,095,736, issued October 12, 1937, with both of these patents being assigned to the assignee of this invention. Accordingly, for a more detailed description of the exact construction of these parts and their method of assembly, reference is hereby made to the above-mentioned patents.

In brief, the operation of the fuse thus far described is as follows. Upon the passage of currents greater than a magnitude predetermined by the fusible means 64, the means 64 are melted to thereby allow the coil tension spring 18 to move the piston 72 and the arc drawing rod 68 upwardly within the fuse tube 54, to thereby elongate or draw out the'arc formed by fusion of the fusible and strain means 64, into intimate engagement with the gas-evolving material 62 to thereby increase the arc voltage and cool the arc to extinguish the same. A releasable closure I is mounted in the lower, open end of the refill element, and is adapted to be blown out of the lower end of the refill element upon the occurrence of a predetermined gas pressure within the fuse.

I have shown in detail in Figs. 2 to 6 the specific construction of the upper end of the fuse which enables the same to become automatically disengaged from the latch 32 in response to blowing of the fuse. The upper fuse terminal cap assembly 46, includes a sleeve portion 80 having a lower inwardly extending flange 82 for cooperation with an outwardly extending flange B4 on the upper end of the fuse tube 54 to limit outward movement of the fuse terminal cap assembly 46 with respect to the fuse tube 54. The sleeve 80 is freely slidably mounted on the fuse tube 54 and packing material 86 is provided between the sleeve flange 82 and the fuse tube flange 84 for a purpose to be hereinafter described. The packing material 86 is preferably a resilient material such, for example, as rubber or the like. A cover cap 88 carrying the latch engaging projection 44 is threadedly engaged with the upper end of the sleeve 80 and with the conducting rod I4. Threadedly engaged with internal threads provided on the sleeve 00 is a conductor rod support 90 provided with a central circular aperture 92 for receiving the conductor rod I4 (Fig. 6), and

also provided with an elongated slot 94 extending therethrough for receiving an integral pin 91 provided on the conductor rod I4. Above the slot 94, there is provided a notch in the upper surface of the support 90 which provides shoulders 96 and 08 on opposite sides of the slot 94. Upwardly extending projections 99 are provided at the inner edges of shoulders 06 and 98 adjacent the outer ends thereof for maintaining pin 91 in the dotted line position shown in Fig. 6. The central portion of the outer ends of the upper notch are cut slightly deeper as at I00 to provide notches for the reception of a tool for rotating the support 90 for threadedly engaging or disengaging the same from the sleeve 80. An operating sleeve member I02 having a central opening which is substan tially square in cross-section, as seen. in Figs. 3 and 4, to conform to the cross-section of rod I4 so as to be slidably but nonrotatably mounted on the squared depending portion of the conducting rod I4. The sliding movement of the operating member I02 is limited between the supporting member 90 and the stop I04 mounted on the lower end of the conducting rod I4. The operating sleeve I02 has secured to its lower end, the upper end of the coil tension spring I0, as for example, by the spring being tightly coiled in corresponding notches in the sleeve I02. Supporting levers I06 are pivotally mounted on the upper end of the fuse tube 54 for supporting the upper fuse terminal cap assembly 46 in an extended position normally, with respect to the fuse tube 54. As shown in Fig. 5, each supporting lever I06 includes a pivot aperture I08, an upwardly extending laterally curved supporting arm H0, a laterally extending actuating arm H2, and a stop lug H4 spaced from the pivot aperture I08. As shown in Figs. 2 to 4, these supporting levers I00 are pivotally mounted on pivot supporting lugs H6 provided integral with the upper end of the fuse tube and are provided with l spring H8 about 75 slot 04 provided in the supporting'member 00..

iii)

the outer end of each pivot .pin which coil springs normally urge the supporting levers in a direction to move the supporting arms I I0 thereof into a position in which they are parallel with the top of the fuse; or as viewed in Fig. 3, the coil spring I I8 tends to move the supporting lever I06 shown in Fig. 3 in a clockwise direction about its pivot aperture I08. The levers are normally prevented from moving by a flange I provided on the upper end of the operating sleeve I02 which engages the top surfaces of the actuating arms I I 2 of the supporting levers I06. Operating sleeve I02 is also provided with inwardly extending opposed notches on its periphery at I22 for a purpose to be hereinafter described.

In the position shown in Figs. 2 to 4, it is obvious that the tension on coil spring I8 maintains the operating sleeve I02 in the lower position as shown in Fig. 2, thereby maintaining the supporting levers I06 through the actuating arms I I2 thereof, in a vertical position or a position in which the supporting arms IIO are substantially vertical so that the upper terminal cap assembly is maintained in the extended position shown.

When the fuse blows, as previously described, the coil spring I8 operates to move the arc drawing rod 68 upwardly, and inasmuch as the spring I8 is no longer anchored at its lower end, it no longer is able to maintain the operating sleeve I02 in the position shown in Fig. 2, whereupon the coil springs I I8 mounted on the pivot pins for the supporting levers I06 are free to rotate their corresponding levers into a position where the supporting arms I I0 thereof no longer act to maintain the upper fuse terminal cap assembly I06 in the position shown in Fig. 2, whereupon the entire assembly 46 is free to slide downwardly on the fuse tube 54, which movement is given an initial impetus by the latch 32 under the influence of its spring 38, since the latch 32 is free to move downwardly a slight distance before it engages its stop 36. The compressed packing material 86, likewise is available to aid in initially moving the upper terminal assembly 46 downwardly and, under these initial forces, the assembly 46 is moved to the position shown in dotted lines in Fig. 1, aided, of course, by the force of gravity, so that the projection 4-4 on the cover 88 of the assembly 46 is moved to a position spaced below the latch 32 so that it is disengaged therefrom, and the leaf spring 25 on the lower insulator cap 8 is then free to move the fuse I4 in a clockwise direction about its trunnions 20 to an open position, such as previously described.

Having moved to such an open position. the fuse may then be removed and refused by removing the clamping plug and the refill from the bottom substantially in the same manner out lined in the previously mentioned Rawlins patent.

. The cover 88 for the upper terminal cap assembly 46 is then unscrewed from the sleeve and conductor rod I4. The conductor rod is kept from rotating by pin 9] which normally lies in the notch in the supporting member diagonally of the same, as shown in dotted lines, Fig. 6. The

This also causes operating sleeve I02 to rotate to bring itsperipheraI notches I22 into alignment with the operating arms H2 of the supporting levers I66, whereupon the entire spring and shunt assembly is free to move downwardly out of the lower end of the fuse tube 54. The reverse process is gone through after a new refill has been fastened to the spring and shunt piston I2. The conducting rod M is drawn upwardly through the fuse tube by any suitable operating rod which is adapted to be threadedly engaged with the threaded upper end of the conducting rod I4, until the flange I26 on the operating sleeve I62 lies above the actuating arms I I2 of the supporting levers I66. The conductor rod I4 is then rotated so as to bring the notches I22 in the operating sleeve flange I23 out of alignment with the actuating arms on the supporting levers and simultaneously move the supporting pin 97 on the conductor rod 14 to a position diagonally above the slot 54, in the supporting member 96; then when the rod M is released, spring I8 will operate to move the operating sleeve I212 downwardly into engagement with the actuating arms H2 of the supporting lever I66, to rotate these levers to a position in which the supporting arms H9 thereof are substantially vertical, thereby moving the entire upper terminal cap assembly 46 to an extended position, substantially as shown in Fig. 2. The coil tension spring I8 is, of course, stronger than the coil springs H8 so as to be able to move the supporting levers Hi6 against the bias of springs H8. In the event that the assembly 46 is not moved fully to the position shown in Fig. 2 by spring T8, the assembly may be manually grasped and moved outwardly to compress the packing material 86 and permit the supporting arms H of the actuating levers I06 to be moved to a fully vertical position, as shown in Figs. 2 to 4. The top cover 83 is then screwed into position and the fuse is ready to be reinserted in the circuit in the marmer already described. It should be noted that the packing material 66 serves the dual function of preventing the entrance of moisture or other contamination from the atmosphere into the fuse and also serves to aid the latch 32 in imparting an initial force to the movable terminal assembly 46 downwardly, after the fuse blows.

A slightly modified form of terminal assembly supporting lever is shown in Fig. 7, wherein the v numeral I24 designates a supporting lever much like the lever I96 shown in Fig. 5. The lever I24 includes a supporting arm I26 like the supporting arm Iill, a laterally extending actuating arm :28 and a stop lug I30. The lever I24 differs from the lever I06 in that the pivot aperture I 32'thereof is positioned eccentrically with respect to the supporting arm I26 of the lever so that the springs H8 for moving the levers IDS to a non-supporting position may be eliminated when a lever like the lever I24 is used in the structures shown in Figs. 1 to 4 and 6. It is believed that it will be obvious that when a lever similar to the lever I24 is provided in place of the lever I06 in a fuse structure such as that shown in Figs. 1 to 6, that it will be held in position by the actuating sleeve I82 in the same manner as levers I68 are held in place. However, when the upper terminal cap assembly 46 is urged to move downwardly following blowing of the fuse, the downward force on the upper end of the supporting arm I26 of the lever I24 will be exerted eccentrically with respect to the pivot supporting aperture I32 of the lever, and thereby will tend to rotate the lever I24 about the aperture I32 in a direction to move the supporting arm I26 to a horizontal position. Thus, by"

moving the pivot aperture for the lever to a position eccentric to the supporting arm of the lever, I may thus eliminate the spring which tends to move the lever to a non-supporting position. Otherwise, the operation of a fuse such as shown in Figs. 1 to 4 and 6 and employing a support lever I24 in place of the supporting lever I06 is exactly the same as that described in connection with the embodiment shown in Figs. 1 to 4, and 6 and therefore, such operation and method of removing the fuse will not be repeated here.

In Figs. 8 and 9 of the drawings, I have shown a slightly modified structure for controlling the supporting levers I66. Inasmuch as most of the parts shown in this embodiment of my invention are the same as those shown in Figs. 1 to 6, I have employed like reference numerals to designate like parts. The main difference in the construction shown in Figs. 8 and 9 over that previously described, is that springs I34 are provided on the operating lever pivot pins, which springs are adapted to normally urge the supporting levers I66 to an upright position as shown in Fig. 9, wherein the stop lugs H4 of the levers are engaged with the upper surface of the fuse tube flange 84. Also, the operating sleeve I36 in this form of my invention is of slightly less extent than the operating sleeve I92 of the first embodiment of my invention, and the upper flange I38 on the operating sleeve I36 is normally positioned to reside beneath, rather than above the actuating arms II2 of the supporting levers I06.

In the operation of this embodiment of my invention, when the fuse blows, as previously described, the coil spring I8 operates to rapidly withdraw the piston 12 upwardly in the tube 54, and with the kinetic energy which it gathers upon moving, it actuates the operating sleeve I36 upwardly, causing the flange I38 on the sleeve to strike the operating arms II2 on the supporting levers I 06 with an impact, to cause rotation of the levers so that the supporting arms III thereof are moved to a horizontal position. Thus, as viewed in Fig. 9, the impact of the operating sleeve I36 tends to rotate the supporting lever I86, seen in this figure, in a clockwise direction about its pivot axis. The springs I34, for normally maintaining or moving the supporting levers I06 so that the arms H0 thereof are in a vertical position, are made relatively weak, in-

asmuch as the only function of these springs is to move the actuating levers to the positions shown in Figs. 8 and 9, when the fuse is assembled or after it is refused. The unlatching and movement of the fuse in this embodiment of my invention, out of engagement with its associated circuit is accomplished in the same manner as described in connection with the first embodiment of my invention. Likewise, refusing or replacement of the refill unit is adapted to be carried out in the same manner as described in connection with the first embodiment, except that, since the actuating sleeve I36 in this embodiment of my invention is shorter than the actuating sleeve I62 in the first described embodiment, the flange I33 on the sleeve will be below, instead of above the actuating arms H2 of the supporting levers I66 when the conducting rod I4 is drawn upwardly through the supporting member to be supported thereby. Therefore, these operations and the method of refusing will not be repeated.

In Fig. 10, I have shown a still further modified form of supporting means for the upper terminal cap assembly 46. Here again, many of the parts are the same as in the previously described embodiments of my invention, so like reference numerals are used to designate like parts. In Fig. 10, I have shown the operating levers as being replaced by toggles, each of which includes a toggle lever I40 pivotally mounted on a lug, integral with the supporting member 90, and a toggle lever I42 pivotally supported on a lug integral with the fuse tube 54. The adjacent ends of the toggle levers I40 and I42 are pivotally connected as shown, and one of the toggle pivots is provided with a biasing spring I44 shown here, as applied to the upper toggle pivot, to normally urge the toggle levers inwardly past dead center position. The lower toggle 1evers I42 are each provided with an integral laterally extending actuating arm I45 adapted to over-lie the flanges I38 on the operating sleeve I36.

The operation of this embodiment of my invention is very similar to that shown in Figs. 8 and 9. When the fuse blows, the kinetic energy accumulated by the coil spring 18 and the parts moved thereby, delivers an impact blow to the operating sleeve I 36 which is imparted to the arm I40 on the toggle levers I42 to move these levers relatively outwardly past their dead center position so that the toggle may collapse, and the upper fuse terminal cap assembly 46 may move downwardly out of engagement with respect to the latch 32, whereupon the fuse can move to an open position, as previously described. The spring I44 on the upper toggle pivot, like the spring I34 described in connection with Figs. 8 and 9, may be relatively weak since the only function which it must perform is to move the toggle levers past their dead center positions when the fuse terminal cap assembly 46 is manually moved outwardly upon assembly of the fuse or upon renewing the refill, following blowing of the fuse.

It should be obvious from the foregoing that I have provided a novel form of fuse construction which will enable the fuse to automatically release itself from a latch holding it in its associated circuit following blowing of the fuse. This release is accomplished by a portion of the fuse enclosure which is normally maintained in an extended position relative to the fuse tube so that it may engage a latch 32, but which is free to move inwardly with respect to the fuse tube following blowing of the fuse to thereby become disengaged from the latch and permit its movement under the influence of the biasing spring, such as 25, to a disconnected position, with respect to its associated circuit.

This particular fuse construction has the advantages of other forms of drop-out fuse, and includes many others, such, for example, as the advantage of providing a totally enclosed fuse, thus preventing entrance of moisture or other substances which may be deleterious to the fuse, or gas-evolving material, to the interior of the fuse. Furthermore, it should be noted that this device cannot become released from the circuit until the are formed by blowing of the fuse is the fuse tube. This gas under pressure can pass between actuating sleeve I02 or I36 and the fuse tube to build up pressure in can assembly 46 tending to maintain the upper terminal cap assembly 46 in its normal position until the arc is extinguished, and no more gas is evolved, whereupon the movable terminal assembly 46 is then free to move downwardly to become released from the latch 32 and permit the fuse to move out of its associated circuit. In other Words, the gas pressure developed by an arc tends to hold the fuse in circuit rather than to accelcrate its disengagement from the circuit.

Having described preferred embodiments of my invention in accordance with the patent statutes, I desire that it be not limited to the particular structures disclosed herein, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modifications may be made in these particular structures Without departing from the broad spirit and scope of my invention. Therefore, I desire that my invention be interpreted as broadly as possible, and that it be limited only by what is expressly stated in the following claims.

I claim as my invention:

1. In a circuit interrupter, an interrupter support embodying relatively movable parts, means on said support for automatically interrupting an electric circuit upon the passage therethrough of currents greater than a predetermined value, means normally maintaining said relatively movable parts in extended partially overlapping relation, and said last-mentioned means being operable in response to an interrupting operation of said interrupting means to permit relative inward movement of said parts toward a more completely overlapped position.

2. In a circuit interrupter, an interrupter enclosure embodying relatively movable parts, means on said enclosure for automatically interrupting an electric circuit upon the passage therethrough of currents greater than a predetermined value, means normally maintaining said relatively movable parts in extended partially overlapping relation, and said last-mentioned means being operable in response to an interrupting operation of said interrupting means to permit relative inward movement of said parts toward a more completely overlapped position.

3. In a circuit interrupter, an interrupter, a tubular support having an end closure slidably mounted on one end thereof, means in said support for automatically interrupting an electric circuit upon the passage therethrough of currents greater than a predetermined value, means normally maintaining said closure in an extended closed position with respect to said support, said last-mentioned means being operable in response to an interrupting operation of said interrupting means to permit said closure to move inwardly of said extended position.

4. In a circuit interrupter, an interrupter, a tubular support having an end closure slidably mounted on one end thereof, stop means including resilient means for limiting outward movement of said closure relative to said support, means in said support for automatically interrupting an electric circuit upon the passage therethrough of currents greater than a predetermined value, closure supporting means normally maintaining said closure in engagement with said stop means with said resilient means i in stressed condition, and said closure supporting means being operable to a non-supporting condition in response to an interrupting operation of said interrupting means, to permitinward movement of said closure member relative to said tubular support.

5. In a high voltage fuse, a fuse tube having an end cap slidably mounted at one end thereof, pivoted supporting means adapted in one position thereof to maintain said cap in an extended position with respect to said fuse tube, means including a fusible element in said fuse tube and extending into cooperative relation with respect to said pivoted supporting means, whereby blowing of said fusible element effects movement of said pivoted supporting means to a non-supporting position with respect to said cap.

6. In a high voltage fuse, a fuse tube having an end cap slidably mounted at one end thereof, pivoted supporting means on at least one of said members, means including a fusible connection for normally maintaining said supporting means in a position to prevent inward movement of said cap with respect to said tube, said supporting means being biased for movement to a nonsupporting position, whereby when said fusible connection blows, said cap is free to move inwardly with respect to said fuse tube.

7. In a circuit interrupter, a tubular casing, means in said casing for automatically interrupting the circuit in response to the passage therethrough of currents greater than a prede-i termined value, said casing including telescoping parts normally maintained in partially telescoped extended relation, and means responsive to an interrupting operation of said interrupting means for permitting inward telescoping movement of said casing parts.

8. In a circuit interrupter, a tubular casing, means in said casing for automatically interrupting the circuit in response to the passage therethrough of currents greater than a predetermined value, said casing including longitudinally movable parts, supporting means movably mounted on one of said parts and biased to a position for preventing inward movement of said parts, and means controlled by said interrupting means in response to an interrupting operation thereof to move said supporting means to a non-supporting position to permit inward movement of said casing parts.

9. In a circuit interrupter, a tubular casing, means in said casing for automatically interrupting the circuit in response to the passage therethrough of currents greater than a'predetermined value, said casing including longitudinally movable parts, supporting toggle means for normally maintaining said parts in an extended position, and means controlled by said interrupting means in response to an interrupting operation thereof to cause said toggle to collapse and permit inward movement of said casing parts.

10. In a circuit interrupter, a tubular interrupter casing movably mounted adjacent one end for movement of a terminal portion adjacent its other end into and out of engagement with a cooperating contact, latch means adjacent said contact for latching said interrupter terminal portion in engagement with said contact, relatively longitudinally movable latch engaging means carried by said casing and normally maintained in an extended position beyond said casing for engagement with said latch means, means in said casing for automatically interrupting the circuit in response to the passage therethrough of currents above a predetermined magnitude,

and-means controlled by said interrupting means "in response to an interrupting operation there- -of,- for permitting inward-movement of 'said latch engaging means" 'to' become disengaged from said latch means, to thereby permit said 'casing'terminal to move out of engagement with respect to said contact.

11. In a'circuit interrupter, a tubular interrupter casing movably mounted adjacent one end for movement of a'terminal portion adjacent its other end into and out of engagement with a cooperating contact, latch means adjacent said contact for latching said interrupter terminal in engagement withsaidcontact, a slidable cap for said other end of said casing normally maintained in an extended position relative to said casing for engagement'with said latch means, means in said casing 'for'automatically interrupting the circuit'in response to the passage therethrough of currents above a predetermined magnitude, and means controlled by said interrupting means in response to an interrupting operation thereof, for permitting inward movement of said cap away from said latch means, whereby saidcasing may move to disengage its terminal from said contact.

12. In' a circuit interrupter, a tubular interrupter casing movably'mounted' adjacent one end for movement of a terminal portion adjacent its other end into and out of engagement with a cooperating contact, latch means adjacent said contact for latching said interrupter terminal in engagement with said contact, a slidable 'cap for said other end of said casing normally maintained in" an extended position relative to said casing for engagement with said latch means, means in' said casing for automatically interrupting the circuit in response to the passage therethrough of currents above apredetermined magnitude, and means controlled by said interrupting means in response to an interrupting operation thereof, 'for'permitting inward movement of said cap away from said latch means, whereby said casing may move to disengage its terminal from said contact, said latch means being biased for limited movement in the direction of inward movement'of said cap, whereby to impart an initial impetus to such movement of the cap.

13. In a renewable'fuse, an elongated fuse tube, a fuse refill unit adapted to be inserted in one end of [said tube, andreleasably secured therein, said refill unit including a fusible element and a pair of fuse terminals, a terminal cap structure slidably mounted on the other'end of said fuse tube, saidcap structure'including a removable end wall'portion adapted to be removably secured to said'cap structure and to an inwardly extending conducting portion, which is in turn conductively and resiliently connected to one of said fuse terminals, means-coacting between said fuse tube'and cap structure to normally maintain said cap structure in an'extended position relative to said tube, means slidably mounted on said conducting portion for actuating said cap supporting means in responseto blowing of said fusible element to permit said cap to move inwardly relativeto said fuse tube, means in said cap structure for supporting said conducting portion when said end wall portion is removed y'and said means being constructed and arranged so that saidconducting portion and actuating'means are removable as a-unit with saidconnection to said one fuse terminal,

from one end of saidfuse tube.

14. In a renewable fuse, an elongated fuse tube, a fuse refill unit adapted to be inserted in one end of said tube, and releasably secured therein, said refill unit including a fusible element and a pair of fuse terminals, a terminal cap structure slidably mounted on the other end of said fuse tube, said cap structure including a removable end wall portion adapted to be removably secured to said cap structure and to an inwardly extending conducting portion, which is in turn conductively and resiliently connected to one of said fuse terminals, means coacting between said fuse tube and cap structure to normally maintain said cap structure in an extended position relative to said tube, means slidably mounted on said conducting portion, outwardly of said cap supporting means for actuating the same in response to blowing of said fusible element to permit said cap to move inwardly relative to said fuse tube, means in said cap structure for supporting said conducting portion when said end wall portion is removed, and said means being constructed and arranged so that said conducting portion and actuating means are removable as a unit with said connection to said one fuse terminal, from said one end of said fuse tube.

15. In a circuit interrupter, a tubular interrupter casing movably mounted adjacent one end for movement of a terminal portion adjacent its other end into and out of engagement with a cooperating contact, latch means adjacent said contact for latching said interrupter terminal in engagement with said contact, said casing embodying telescoping parts one of which is engageable by said latch means when in a normal extended position partially telescoped, means in said casing for automatically interrupting the circuit in response to the passage therethrough of currents above a predetermined magnitude, means controlled by said interrupting means in response to an interrupting operation thereof, for permitting inward movement of said latch engaging part to a more fully telescoped position so as to become disengaged from said latch means, and said latch engaging part having a closed end, whereby pressures developed by an arc in said casing will tend to prevent release of said latch means until said arc is extinguished.

16. In a fuse, a fuse tube, fusible means in said tube, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric are forming a restricted arc passage in said tube, resilient means biasing one terminal of said fusible means for movement through said passage upon fusion of said fusible means to draw out and extinguish the resulting arc, means slidably mounted with respect to said tube, means normally supporting said slidable means in an extended position with respect to said tube, and said last mentioned means positioned to be engaged by a part movable with said resilient means adjacent the end of said arc drawing movement to release said slidable means for inward movement with respect to said tube.

17. In a fuse, a fuse tube, fusible means in said tube, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric are forming a restricted arc passage in said tube, resilient means biasing one terminal of said fusible means for movement through said passage upon fusion of said fusible means to draw out and extinguish the resulting arc, means slidably mounted with respect to said tube, means pivotally mounted on said tube and normally engaging and supporting said slidable means in an extended position with respect to said tube, and said last mentioned means positioned to be engaged by a part movable with said resilient means adjacent the end of said are drawing movement to pivotally move said supporting means to a non-supporting position and thereby release said slidable means for inward movement with respect to said tube.

18. In a fuse, a fuse tube, fusible means in said tube, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric are forming a restricted arc passage in said tube, resilient means biasing one terminal of said fusible means for movement through said passage upon fusion of said fusible means to draw out and extinguish the resulting arc, means slidably mounted with respect to said tube, means pivotally mounted on said tube and normally supporting said slidable means in an extended position with respect to said tube, means biasing said supporting means to said supporting position, and said supporting means positioned to be engaged by a part movable with said resilient means adjacent the end of said are drawing movement to release said slidable means for inward movement with respect to said tube.

19. In a fuse, a fuse tube, fusible means in said tube, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric are forming a restricted arc passage in said tube, resilient means biasing one terminal of said fusible means for movement through said passage upon fusion of said fusible means to draw out and extinguish the resulting are, means slidably mounted with respect to said tube, means pivotally mounted on said tube and normally supporting said slidable means in an extended position with respect to said tube, means biasing said supporting means to a non-supporting position, and said resilient means engaging said supporting means to normally maintain said supporting means in said supporting position, whereby upon fusion of said fusible means said supporting means is released for pivotal movement under the influence of said biasing means to a non-supporting position to permit inward movement of said slidable means with respect to said tube.

20. In a fuse, a fuse tube, fusible means in said tube, means of a material capable of evolving an arc-extinguishing gas when in proximity to an electric are forming a restricted arc passage in said tube, resilient means biasing one terminal of said fusible means for movement through said passage upon fusion of said fusible means to draw out and extinguish the resulting are, an end cap slidably mounted with respect to said tube, means normally supporting said end cap in an extended position with respect to said tube, and said last-mentioned means positioned to be engaged by a part movable with said resilient means adjacent the end of said are drawmg movement to release said end cap for inward movement with respect to said tube.

JAMES M. WALLACE.

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