US2267393A - Electric circuit interrupting apparatus - Google Patents

Description

Dec. 23, 1941. R. s. BENNETT 2,267,393

ELECTRIC CIRCUIT INTERRUPTING APPARATUS Filed Jan. 25, 1940 I0 F12. Z.

15a 82 4* Ava/4.0710

Inventor; Ralph SBenn tt.

is Attorhqg.

Patented Dec. 23, 1941 ELECTRIC CIRCUIT INTERRUPTING APPARAT Ralph S. Bennett, Pittsiield, Mass., assignor to General Electric Company, a corporation of New York Application January 25, 1940, Serial No. 315,556

25 Claims. (01. 200-126) The present invention relates to electric circuit interrupters, and has for one of its principal objects the provision of an improved form and arrangement of gas barrier for preventing arcover between conductive parts of .a circuit interrupter incorporating a circuit interrupting element of the expulsion type.

A more specific object of the invention is the provision, in a circuit interrupter incorporating an expulsion type circuit interrupting element, 01' a movable member operative in one position to serve as a gas barrier and automatically movable to another position to serve as an indicator when the said circuit interrupting element has operated.

Another object is the provision of improved gas barrier means and indicator means for circuit reclosing fuse apparatus incorporating one or more fuse holders of the expulsion type.

As to certain aspects of the invention, a further object is the provision oi. improvements in fuse cutouts such as those disclosed in United States Patents No. 2,169,087, issued August 8, 1939, in my name, and No. 2,165,015, issued July 4, 1939, in the name of L. P. Sohles, both of which patents are assigned to the same assignee as the present invention.

A still fur her object of the invention is the pzovision of improved form of automatically releasable terminal clamp or snubbing device for the flexible cable extension of a fuse link.

Other objects and the details of that which I believe to be novel and my present invention will become apparent from the following description and the claims appended thereto taken in conjunction with the accompanying drawing. While my invention may be incorporated in circuit inteirupters of various forms, and of either the open type or the enclosed type, as will become apparent hereinafter, I have chosen as the best means of conveying a complete understanding of all features of the invention, to illustrate and describe an exemplary embodiment thereof as incorporated in an enclosed circuit reclosing fuse cutout of a general form and arrangement similar to the cutouts disclosed in my patent and the patent to L. P. Sohles previously mentioned. The illustrated cutout also includes certain features forming part of the subject matter disclosed in United States Patents No. 2,164,994, issued July 4, 1939, and No. 2,175,904, issued October 16, 1939, both in the name of G. F. Lincks, and No. 2,164,983, issued July 4, 1939, in my name, which three last mentioned patents also are assigned to the same assignee as the present invention.

In the drawing, Figs. 1 and 2 are sectional elevations showing, respectively, the parts of the exemplary cutout in their normal operative positions, and the relative positions of the parts after operation of one of the fuses; Fig. 3 is a view looking up at the bottom of a portion of the cutout with the parts thereof in the same positions as shown in Fig. 1; Fig. 4 is an enlarged section along the line 4-4 of Fig. 1; Fig. 5 is a side sectional view of certain of the parts shown in Fig. 4; and Fig. 6 shows a detail of certain of the latch parts.

Referring to the drawing, in indicates an electrio cutout casing constructed of porcelain or other suitable insulating material, and which has an electric creepage and gas barrier H disposed between line terminals I2 and i3 mounted on the inner rear wall of the casing. A mounting bar, partially shown at H, is provided for mounting the cutout on an electric line pole, crossarm, or other supporting means. Two hinge brackets l5, one of which is shown in the draw ing, are secured in horizontally spaced relationship to the inner rear wall of the casing adjacent the bottom thereof. Terminals l2 and i3 have clamping means, designated l2 and I3 respectively, to provide for attachment of line conductors or leads thereto. Upper terminal 12 has a contact finger I! backed by a spring strip 18 and having a. spherical seat 19 arranged to receive and press downwardly upon the top of a fuse holder terminal cap. Terminal 12 has also an approximately U-shaped clip 20, the resilient arms of which extend forwardly in horizontally spaced relationship and have inwardly bent detent portions 22 and outwardly flared guide portions 23. Lower terminal i3 includes a contact plate 24.

The illustrated cutout has a pair of fuse holders, 25 and 26, which consist in the main of expulsion tubes of insulating material having contact caps 21. and 28 respectively on the upper ends thereof. Within the fuse holders are accommodated fuse links which are connected at their upper ends with caps 21 and 28, and the lower ends, or cable extensions, of which fuse links extend out the lower discharge ends of the fuse tubes, as indicated at 3! and 32 respectively. Although the exemplary cutout has two circuit interrupting elements of the expulsion type, it will be apparent from the ensuing description that certain features of the invention may be employed to advantage in circuit interrupters having only one such circuit interrupting element, while other features of the invention may be employed to advantage in circuit interrupters having more than two circuit interrupting elements of the expulsion type. The illustrated fuse holders 25 and 26 are maintained in parallel juxtaposition by upper and lower metallic clamps, designated 33 and 34 respectively, and holder 28 is longer than holder 25 so that its lower end projects below the lower end of holder 25. The holders and their supporting clamps constitute part of a unitary assembly adapted for removable installation in a cutout A cutout casing door 35, constructed of suitable insulation material and having a handle 36, is secured to the fuse holder assembly by means of upper and lower U-shaped retaining clips 31 and 38 respectively, which are secured to the irmer face of the door. In accordance \go of suilicient diameter to receive the larger diameter portions 4| of bosses 42 disposed respectively on opposite sides of upper clamp 33. The arms of clip 31 also have elongated slots 13 communicating with openings 40 but only of sufficient width to receive the smaller diameter portions 44 of bosses 42. The arms of lower retaining clip 38 have slots and communicating relatively narrower slots 46, designed to receive the larger diameter portions 41 and the smaller diameter portions 48, respectively, of bosses which are disposed on opposite sides of lower clamp 34. Normally, the larger diameter portions 4! of bosses 42 are in engagement with the larger diameter openings 40 in the arms of clip 31, while the larger diameter portions 41 of bosses 50 are in engagement with the wider slots d5 in the arms of clip 38. Thus, the upper ends of the fuse holders are prevented from lateral movement relative to the door, while the wider slot portions in lower clip 38 provide for a small amount of lateral movement of the lower ends of the holders relative to the door. When it is'desired to refuse holder 25, the arms of retaining clips 31 and 38 are spread apart sufllciently to permit the smaller diameter portions of bosses 42 and 56 to travel in the narrower slots 43 and 46 of clips 31 and 38 respectively, and the fuse holder assembly is moved outwardly from the door recess to the extent permitted by the lengths of the narrower slots,

without complete detachment of the assembly from the door. This affords ready access to cap 23 for removal thereof and refusing of holder 26. After refusing, the assembly is pressed back into its normal position in the door recess.

A toggle lever 52 is provided for supporting the fuse holder and door assembly on casing ID. This toggle lever has arms 53 maintained rigidly in spaced relationship by cross pieces 54 and 55. One end of each of the arms 53 has a hook portion 56 for engagement with the hinge pin 51 of a respective one of the brackets IS. The other ends of arms 53 are pivoted on a pin 58 extending between spaced arms 59 of a terminal element 60 fixedly secured on the lower end of fuse holder 25. Normally, toggle lever 52 is held in substantially rigid relation to holder 25 by fuse link cable 3! which is anchored to the lower portion of terminal element 60 by a clamp 6|, the cable 3i being passed around a projection 62 formed integrally with cross piece 55 of the toggle lever. With the toggle lever pivoted on hinge brackets i5 and held rigidly with respect to holder 25, the fuse holder and door assembly may be swung into and out of operative position, illustrated in Fig. 1, by means of handle 38. Latching of the upper end of the assembly in operative position is effected by engagement of detent portions 22 of upper terminal clip 20 with cooperative detent portions 63 adjacent the ends of the arms of upper retaining clip 31, as shown in the detail view of Fig. 6..

The fuse holder assembly is held in operative position so long-as the fuse link in holder 25 remains intact, and, as will be pointed out hereinafter, this latter fuse link is arranged to be the last or final one to operate.

With the fuse holder assembly in operative position, the upper ends of the fuse links in both of the holders are connected with upper casing terminal 12, due to engagement of contact finger l1 with fuse holder cap 21 and the electric interconnection afforded between caps 21 and 28 by metallic clamp 33. For connecting the lower ends of the fuse links with lower casing terminal 13, there is provided a metallic contact shoe 64 which is arranged to engage contact plate 24. This contact shoe is pivoted on the upper end of an insulating arm 65 which is pivotally supported at its lower end on a pin 66 extending between spaced arms 59 of fuse terminal 60. Arm is biased by means of a coil spring 61 to effect pressure engagement between contact shoe 84 and contact plate 24. Normally, fuse terminal 60 is electrically isolated from lower casing terminal l3 by reason of the fact that arm 65 is constructed of insulation. Another fuse terminal 10 is mounted on the inner face and adjacent the bottom of door 35. This terminal is of generally U-shaped construction and the ends of the legs thereof are secured to the door by screws 1|, as will be seen best from Fig. 3. Terminal 10 is electrically connected with lower fuse holder clamp 34 by means of two flexible conductors 12 which are anchored at one end respectively under the ends of the legs of terminal 10, and the other ends of which conductors are anchored to clamp 34 by screws 13, respectively on opposite sides of the clamp. Two more flexible conductors 14 extend from the anchoring points 13 respectively on opposite sides of the fuse holders, and are connected with contact shoe 84 as shown at 15. Conductors 12' and 14 complete electric connection between fuse terminal 10 and contact shoe 64 while providing for relative movement between the fuse holders, the door, and contact supporting arm 65.

For connecting the cable extension 32 of the fuse link in holder 26 with terminal 10, I have provided an improved clamping or snubbing device comprised of a socket element 16 and a cooperating tongue 11, the details of construction and arrangement of which will be seen best from Figs. 3, 4, and 5. Both the socket element and the tongue are pivoted adjacent their upper ends on a pin 18 extending between the legs of terminal 1G. The upper part of the socket element. which is disposed between the legs of terminal 19, is of generally U-shape, having a base poraao'asos tion 18 and spaced apart depending leg p rtions 88. On the lower ends of leg portions 88 are extensions" which converge toward each other in the direction of fuse holder 28, so as to provide a generally V-shaped socket, the apex of which is open toward holder 28. A transversely extending flange or foot 82 is formed intergrally with extensions 8| and projects in the direction of holder 28 for a purpose to be pointed out hereinafter. The upper end of tongue 11 is accommodated between the legs of the upper U-shaped part of socket element 18 and the lower end of the tongue is arranged to swing into and out of the socket provided by extensions 8|.

In securing fuse link cable 82 to the clampin device just described, the fuse holder assembly is pressed into the recessed door as far as permitted by slots 45 in retaining clip 38. Then cable 82 is looped around tongue 11 and over the rearwardly extending projection 88 on the tongue, with the ends of the loop extending out of the open apex of the socket formed by extensions 8|, as shown in Fig. 3. While still pressing the fuse holder assembly into the door, the loop of the cable is drawn as tightly as possible around the tongue. Then the fuse holder assembly is released so that it tends to spring away from the door under the influence of a leaf spring 84. The resultant tension on the fuse link pulls tongue 11 tightly into socket element 18 so as tightly to clamp the loop of the cable between the edges of the tongue and the walls of extensions ll of the socket element. The socket element is restrained from swinging in a clockwise direction, as viewed in Figs. 1 and 5, under the influence of the pull exerted on the tongue, by engagement with the cross piece 85 connecting the legs of U-shaped terminal 18. Thus, the greater the tension on the fuse link in holder 28 due to the action of spring 84, the more tightly is cable 82 clamped in socket element 18. One of the important advantages of the clamping device just described is that the f link cable extension may be secured thereto very quickly and easily, and without the aid of any tools.

With cable 82 connected with fuse terminal 18 in the manner described in the previous paragraph, the fuse link in holder 28 normally is connected between stationary terminals l2 and II, the circuit extending from terminal I2 through contact finger l1, terminal cap 21, upper fuse holder clamp 88, terminal cap 28, the fuse link in holder 28 and its extension 82, clamping device 18, 11, terminal 18, conductors 12 and 14, and contact shoes 84 to contact plate 24 of lower terminal l8. As previously indicated, the fuse link in holder 25 normally is disconnected at its lower end from terminal II.

A time delayed circuit reclosing mechanism is provided for effecting reclosure of an electric circuit through the fuse link in holder 25 upon operation of the fuse link in holder 28. Although various forms of circuit reclosing mechanism may be employed, there is illustrated for purposes of example a circuit reclosing mechanism of the form disclosed and claimed in the previously identified patent of L. P. Sohles. Sufilcient of the details of this mechanism will be set forth herein to convey a proper understanding of the present invention. A casing 88 is secured to a depending extension on the outer end of fuse holder clamp 34 by means of screw 81, which serves also to anchor one end of spring 84. Casing 88 depends from clamp 84 and encloses a time delay mechanism which may be of the mechanical escapement type more fully described in the Sohles patent, or may be of any other suitable type. The time delay mechanism is connected with a switch supporting element 88 which is mounted for vertical sliding movement in guides 88 supported by casing 88. Element 88 is biased downwardly by a coiled compression spring 8| which is supported on a rod 82 anchored at its upper end to the extension (ifclamp 84. On a pivot pin 83 carried by element 88, there is pivotally mounted a U-shaped switch element or transfer contact 84, the spaced apart arms of which are arranged to pass upon opposite sides of the fuse holder assembly. Transfer contact 84 is biased for counterclockwise rotation, as viewed in Figs. 1 and 2, by a spring 85. Two flexible conductors 88, one of which is shown in the drawing, serve to interconnect the transfer contact with terminal 18. On the bottom of the transfer contact is mounted a plate member 81, preferably constructed of insulation material, which has a downwardly extending toothed projection 88 and an opening 88 of sufficient size to accommodate the lower end of fuse holder 28.

In practice, the circuit reclosing mechanism is set prior to securing fuse link cable 32 to the clamping device on terminal 18. In the setting of the reclosing mechanism, transfer contact 84 is rotated into a position extending substantially parallel with holder 28, and then the transfer contact and its supporting element 88 are pushed upwardly, compressing spring 8|, until the ends of the transfer contact arms are disposed behind stops |88 depending respectively from opposite sides of clamp 84. These stops restrain the transfer contact in open circuit position. The transfer contact is latched in its upper position by swinging the foot 82 of socket element 18 under projection 88 and then fastening the socket element by securing fuse link extension 32 thereto in the manner previously described. When the transfer contact is latched in its upper position, plate 81 extends transversely of and in surrounding relation to holder 28, at a point above the discharge end of holder 28 and slightly below the discharge end of holder 25, as shown in Fig. 1. Under these circumstances, plate 81 extends into close proximity with, and to some extent overlaps, the discharge end of holder 25. One important advantage of the arrangement of plate 81 is that the necessity for registry of the opening in the plate with the lower end of holder 28 makes it impossible to set the reclosing mechanism unless the transfer contact is in proper position.

Upon operation of the fuse link in holder 28 due to overload or short-circuit, the tension on cable 82 is released and the cable drops or is expelled downwardly from the lower end of holder 28. Clamping device 18, 11 is so arranged that the cable tends to swing to the right, as viewed in Fig. 1. about the end of the cable which is anchored to the clamping device, and this changes the direction of pull on tongue 11 so that the clamping action of the tongue is released. This permits the cable to drop free of the clamping device, which is of great advantage in that it leaves no live parts dangling beneath the cutout housing. Release of the tension on cable 82 also permits socket element 18 to swing in a counterclockwise direction toward door 35 under the influence of the pressure exerted on the foot 82 by the downwardly biased transfer contact 84. The transfer contact, with its supporting element 88 thereupon moves downwardly under the influence of spring 9i until the arms of the transfer contact become disengaged from stops. Hill, whereupon the transfer contact arms swing, with a snap action movement due to spring 95, in a counterclockwise direction and into engagement with contact stops Nil respectively on opposite sides of fuse terminal 60. This completes connection of the lower end of the fus link in holder 25 with fuse terminal 10, thereby reclosing the circuit between casing terminals l2 and I3. However, downward movement of element 89 to release the transfer contact arms from stops Hill, is retarded by the time delay mechanism in casing 96. This tim delay mechanism is adjusted so that release of the transfer contact arms for movement to circuit reclosing position does not occur until suiiicient time has elapsed for interruption of any temporary fault current in fuse holder 26. One of the important advantages of the illustrated cutout is thatlatching foot 82 is movable to release the transfer contact independently of any movement of the door, so that the reclosing mechanism may operate even though the door is frozen shut by sleet.

With the fuse holders compactly arranged as ilustrated, there may be some danger of areover between conductive parts associated respectively with the lower ends of the fuse links in the two holders due to conductive gases discharged from holder 25, which gases tend to mushroom and eddy up about the lower end of holder 25. Such arc-over might result in reclosure of the circuit through the fuse link in holder 25 before the desired time interval has elapsed for proper reclosure of the circuit by transfer contact 94, in which case th fuse link in holder 25 might be caused to rupture n the same temporary fault which caused rupture of the fuse link in holder 26. The danger of occurrence of such undesirab e arc-over is greatly minimized in the cutout illustrated by reason of the fact that the discharge end of holder 26 projects substantially below the discharge end of holder 25. As a result of this expedient it is insured that more time will elapse before the mushrooming and eddying gases from the lower end of holder 26 approach sufficiently close to the lowerend of holder 25 to cause arcover, and this may be suflicient to allow proper c'earing of the temporary fault in holder 26 and proper circuit reclosure by the transfer contact.

In order still more effectively to insure against undesirable arc-over such as referred to in the previous paragraph, I have, in accordance with one aspect of the present invention, so arranged operation of the first fuse. If desired, the bar-- rier may be painted some bright color to render it more conspicuous. The movement of the barrier to its second position has the further advantage that the barrier is withdrawn from proximity of the discharge end of holder so as not to interfere with sumequent discharge of gases from this last mentioned holder.

lnrcase of continuing or recurring fault, subsequent to closure of the transfer contact, the fuse link in holder 25 operates. This releases the fuse link cable3i so as to permit movement of toggle lever 52 relative to the holder 25, whereupon the fuse holder and door assembly swings outwardly and'downwardly in a well known manner to a dropped-out position, wherein the fuse holders are disconnected from stationary terminals I2 and i3.

Barrier 9? has, in addition to the advantages previously painted out, the further advantage that it tends to retard passage of gases from the dis charge end of holder 26 up into the cutout hous ing where they might cause arc-over between the stationary terminals. In order further to against arc-over between the terminals due to gases rising into the cutout housing from the discharge ends of either of the fuse holders, there plate member 97 that it serves as a gas barrier for retarding movement of gases from the discharge end of holder 26 in the direction of the discharge end of holder 25, and shields the conductive parts associated with fuse link cable 3| from such gases. The action of barrier 91 in deflecting the upwardly moving gases becomes increasingly effective as the barrier moves downwardly with transfer contact 94. By th time the barrier-reaches the lower end'of holder 25, the time delay period wil have elapsed so that the shielding action of the barrier no longer is needed. The barrier is so adjusted that it is moved free of the lower end of holder 26 by the time the arms of transfer contact 94 become free from stops I00. Then as the transfer contact swings to closed position, the barrier swings to its position shown in Fig. 2 wherein a portion of the barrier projects below the cutout housing to give a clearly observable indication of the is provided a barrier plate I02 of a suitable instrlating material disposed intermediate the ends of the fuse holders and extending transverse}? of the holders into cooperative relationship with the casing barrier II and a barrier I93 formed integrally with door 35.

Although, for purposes of conveying a complete understanding of all aspects of my present invention, I have shown and described in considerable detail an exemplary embodiment thereof, it is to be understood that the invention is not limited in application or in details of construction and arrangement to this particular embodiment, and I desire that such modifications or other applications as do not depart from the true spirit of the invention shall come within the scope of the appended claims.

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

1. In a circuit interrupting apparatus including an expulsion tube and means operable to effect interruption of electric current how in said tube with accompanying arcing and expulsion of gases from the tube, a movably supported barrier positioned to retard. movement of such gases in a predetermined direction from the discharge end of said tube, and means operative dependently upon operation of said first mentioned means for effecting movement of said barrier relative to said tube to an indicating posltion.

2. In a circuit interrupting apparatus including a housing, an expulsion tube in said housing, and means operable to effect interruption of electric current in said tube with accompanying arcing and expulsion of gases from the tube; a movably supported member positioned to serve as a barrier for retarding movement of such gases in a predetermined direction from the discharge end of said tube, and means operative dependently upon operation of said first mentioned means for effecting movement of said member relative to said tube to a position wherein at least 9, portion of the member projects from said housing.

3. In a circuit interrupting apparatus including a housing having an open bottom, an expulsion tube in said housing with its discharge end positioned for discharge of gases from the bottom of the housing, and means operable for acevgsos effecting interruption of electric current in said tube; a member movably supported adjacent the discharge end of said tube and arranged to serve as a gas barrier, and means operative dependent- 1y upon operation of said first mentioned means for effecting movement of said member to a position wherein at least a portion of the member projects from the bottom of said housing.

4. In a circuit interrupting apparatus includingan expulsion tube and means operable to effect interruption of electric current flow therein with accompanying arcing and expulsion oi gases from the tube, a gas barrier normally positioned intermediate the ends of said tube, and means operative dependently upon operation of said first mentioned means for effecting movement of said barrier substantially longitudinally of said tube in the direction of the discharge end of the tube.

5. In an electric circuit interrupting and reclosing apparatus, the combination of an expulsion tube, means operable to effect interruption electric current flow in said tube, circuit reclosing mechanism including a movable contact device, and a gas barrier supported on said device for movement from one position to another position upon operation of said mechanism.

6. In an electric circuit reclosing apparatus, a circuit interrupting element including an elongated tubular holder; circuit reclosing mechanism including a transfer contact device normally in open position, and means operative responsively to operation of said circuit interrupting element for effecting movement of said device substantially longitudinally of said holder toward one end of the holder and then laterally relative to the holder to a circuit closing position; and a member supported in fixed relation to said device for movement therewith and having an opening for accommodating said holder, which said member is disposed in surrounding relation to the holder adjacent said end of the holder when the contact device is in normal open position.

7. In an electric circuit interrupting and reclosing apparatus, the combination of an expulsion tube, means for effecting interruption of electric current flow in said tube, circuit reclosing mechanism including a movable contact, a movably supported gas barrier disposed adjacent the discharge end of said tube, and means operative dependently upon operation of said first mentioned means for effecting movement of said barrier from one position to another position and movement of said contact to a circuit reclosing position.

8. In an electric circuit interrupting and reclosing apparatus, the combination of an expulsion tube, means operable to effect interruption of electric current flow in said tube, circuit reclosing mechanism, and a gas barrier automatically movable from one position to another position in'response to operation of said circuit reclosing mechanism.

9. In a circuit reclosing apparatus, the combination of spaced line terminals, 9. housing, a circuit interrupting element in said housing and connected between said terminals, said element including an expulsion tube and means operable to interrupt electric current in said tube with accompanying arcing and expulsion of gases from the tube, circuit reclosing mechanism, a movably supported member positioned to serve as a gas barrier for retarding movement of expelled gases in a predetermined direction from tive dependently upon operation of said mechanism for efiecting movement 01 said member to a position wherein at least a portion of the member projects from said housing. I

10. Electric circuit reclosing apparatus comprising in combination, spaced line terminals, a plurality of circuit interrupting elements, each including an expulsion tube and means operable to effect interruption of electric current flow therein, housing means for said elements, means for connecting one of said elements between said terminals, transfer mechanism for connecting another of said elements between said terminals, 2. movably supported member positioned to serve as a barrier for shielding certain conductive parts connected with said other element from are gases expelled from the expulsion tube of said one element, and means operative dependently upon operation of said one element for effecting movement of said member to a position wherein at least a portion of the member projects from said housing means.

11. In an electric circuit interrupting apparatus including spaced line terminals, a plurality of circuit interrupting elements, at least one of which elements includes an expulsion tube together with means operable to effect interruption of electric current flow therein with accompanying arcing and expulsion oi gases from the tube, and means for selectively connecting said elements between said terminals; a movably supported member normally positioned to serve as a gas barrier for shielding certain conductive parts associated with other of said elements from gases expelled from said tube upon operation of said one element, and means operative dependently upon operation of said one element for effecting movement of said member from its said normal position.

12. In a circuit reclosing apparatus including spaced line terminals, a plurality oi electric cincuit interrupting elements, one of which ele ments is electrically connected between said ter minals and includes an expulsion tube together with means operable to effect interruption of electric current in said tube with accompanying arcing and expulsion of gases from the tube, and transfer mechanism for connecting a second oi said elements between said terminals upon operation of said one element; a member automatically movable from one position to another position in response to operation of said transfer mechanism, which said member when in its said one position is operative to serve as a gas barrier for shielding certain conductive parts associated with said second circuit interrupting element from gases expelled from said tube upon operation of said one element.

13. Circuit reclosing apparatus comprising in 50 combination, spaced line terminals, a circuit in terrupting element connected between said terminals and including an expulsion tube with means operable to eilect interruption or electric current in the tube, a second circuit interrupting element normally disconnected from at least one of said terminals, transfer mechanism for completing connection or said second element between said terminals, a movably supported member positioned to serve as a barrier for shielding certain conductive parts connected with said second element from gases expelled from said tube upon operation of said first mentioned element, and means operative responsively to operation of said first element for efiecting movethe discharge end of said tube, and means opera- "Iii ment of said member to an indicating position.

14. Circuit recloslng apparatus comprising in combination, spaced line terminals, a circuit interruptmg element connected between said terminals and including an expulsion tube, a second circuit interrupting element disconnected from at least one of said terminals and including a second expulsion tube supported with its discharge end in relative proximity to the discharge end of said first mentioned tube, transfer mechanism operable to complete connection of said second element between said terminals upon operation of said first mentioned element, a movably supported member having a portion disposed in proximity with the discharge end of said second tube and operative to shield certain conductive parts associated with said second element from gases expelled from said first tube, and means operative to effect movement of said member from one position to another position relative to the discharge end of said second tube upon operation 01 said first element.

15. In combination, spaced line terminals, 9. first and a second expulsion tube supported with their discharge ends in relative proximity, a first and a second conductor respectively in said first and said second tubes and each connected at one end with one of said line terminals, the other end of said first conductor being connected with terminal means adjacent the discharge end of said first tube and connected with the other of said line terminals, the other end of said second conductor being connected with terminal means adjacent the discharge end of said second tube and normally disconnected from said other line terminal, overload responsive means including said first conductor operative to effect interruption of electric current in said first tube, transfer mechanism for completing electric connection of said second conductor between said line terminals, a gas barrier for preventing arcover between said first and second mentioned terminal means due to gases discharged from said first tube, a portion of said barrier extending in relative proximity to the discharge end of said second tube, and means operative responsively to operation of said overload responsive means for effecting movement of said barrier relative to the discharge end of said second tube.

16. Electric circuit interrupting apparatus comprising a first and a second expulsion tube supported with their discharge ends in relative proximity and respectively having a first and a second fuse link therein.with one end of each fuse link extending out the discharge end of the corresponding tube, terminal means common to the other ends of said fuse links, another terminal means electrically connected with the outwardly extending end of said first fuse link and normally electrically disconnected from the outwardly extending end of said second fuse link, switching mechanism for completing connection of said second fuse link with said other terminal means, a barrier positioned to shield said second fuse link and associated conductive parts from gases discharged from said first tube upon operation of said first fuse link, and means operative dependently upon operation of said first i'use link for effecting movement of said barrier relative to said second tube to an indicating second fuse link respectively in said first and second tubes, each fuse link having one end extending out of the discharge end of its corresponding tube, means connecting said one end of said first fuse link with one of said line terminals, the said one end of said second fuse link being disconnected from said one line terminal, means connecting the other ends of both said fuse links with the other of said line terminals, time delayed circuit reclosing mechanism operative to complete connection of said second fuse link between said terminals upon operation of said first fuse link, a member having a portion extending in relative proximity to the discharge end of said second tube and positioned to shield said second fuse link and associated conductive parts from are gases discharged from said first tube upon operation of said first fuse link, and means including said circuit recloslng mechanism operative to effect a delayed movement of said member from its aforesaid position to another position relative to said second tube upon operation of said first fuse link.

18. In a circuit reclosing fuse apparatus, the combination of a housing comprising a casing having spaced contacts therein and a door for said casing, an expulsion fuse holder supported in said housing, a fuse link in said holder and having a flexible connection conductor extending from one end of the holder, means for connecting the fuse link in an electric circuit and including a terminal mounted on said door, means tensioning the fuse link including quick releasable clamping means connecting said conductor with said terminal, mechanism automatically operable for effecting circuit reclosure upon rupture of said fuse link, means controlled by the tension on the fuse link for releasably restraining said mechanism against reclosing operation, and means operative upon rupture of the fuse link to efiect release of said conductor from said clamping means.

19. In a circuit recloslng fuse apparatus, the combination of a housing comprising a casing and a door for the casing, an expulsion fuse holder in said casing, a fuse link in said holder and having a flexible extension protruding from one end of the holder, means to connect said fuse link in an electric circuit including a terminal having a quick releasable clamping device for connecting said conductor therewith, means including said device operative to tension the fuse link, said device being maintained in clamping engagement with said conductor by the tension on said fuse link and being arranged automatically to release said conductor upon rupture of the fuse link, mechanism operable automatically to effect circuit reclosure when the fuse link ruptures, and a latching element for restraining said mechanism against reclosing operation, which said element is releasably held in latching position by connection of said conductor with said clamping device and is automatically movable out of latching position independently of any movement of said door upon rupture of said fuse link. 7

20. In a fuse device including a fuse link having a flexible connection conductor; tensioning means for said fuse link including a clamping device for said conductor, which said device comprises a first part arranged to resist the pull of said conductor when the fuse link is tensioned, said part having spaced elements forming an opening therebetween, and a second part movable relative to said first part and arranged substantially to bridge one side of said opening, the said tensioned connection conductor extending into said opening from the other side thereof and being looped around said second part in a manner tending to draw said second part through said opening, and said second part under the influence of the pull exerted thereon by said conductor being operative to clamp the conductor between said second part and said spaced elements of said first part.

* 21. In a fuse device including a fuse link having a flexible connection conductor, and means for tensioning the fuse link; quick releasable clamping means for said conductor comprising a first part arranged to resist the pull of the conductorwhen said fuse link is tensioned, said part having spaced leg portions forming an opening therebetween, and a second'part movable relative to said first part and arranged substantially to bridge one side of said opening, said conductor extending into said opening from the other ing a flexible connection conductor, and means for tensioning the fuse link; quick releasable clamping means for said conductor comprising a first part arranged to resist the pull of the condoctor when the fuse link is tensioned, said part having spaced leg portions forming therebetween a space open toward two opposite sides and one end of said part, and a second part supported movabiy relative to said first part at a point spaced from the open end of said first part and extending generally parallel with said leg portions in the direction of said open end of said first part, said second part being arranged substantially to bridge said space on one of the said open sides thereof, and said conductor extending into said space from the other open side thereof and being looped around said second part in such manner that the pull exerted on said second part due to the tension on said conductor causes said second part tightly to clamp'portions of the conductor between said second part and said leg portions of said first part.

2.3. In a fuse device including an expulsion fuse said second part being arranged substantially to bridge said space on one of said open sides thereof, said conductor extending into said space from the other open side thereof and being looped around said second part in such manner that the pull exerted on said second part by said conductor when the fuse link is tensioned, causes said second part tightly to clamp portions of the conductor between the second part and said leg portio ns of said first part; and means supporting said clamp in such relation to said one end of said holder that the movement of said conductor following operation of said fuse link is effective to cause said clamping parts to release the conductor.

24. In a fuse device including an expulsion fuse holder, a fuse rink therein having a flexible connection conductor extending from one end of the holder, and tensioning means for the fuse link; a quick releasable clamp for said conductor, dis- Posed adjacent said end of said holder and comprising a socket element operative to resist the pull of said conductor when said fuse link is tensioned, said element having means forming a socket open on two opposite sides of the element respectively toward and away from said holder, and open also toward one end of said element, the spaced opposed walls of said socket converging so that the open side thereof toward said holder is relatively narrower than the open side away from the holder, and a tongue pivoted relative to said element at a point spaced from said open end of the element and arranged in sub-- stantial registry with said socket on the wider open side thereof, said conductor extending into said socket through said narrower open side and being looped around said tongue in such manner that the tongue, under the influence of the pull exerted thereon by said conductor when the fuse link is tensioned, is operative to clamp portions of the conductor tightly between the tongue and the walls of said socket.

holder, a fuse link therein having a flexible connection conductor extending from one end of the holder, and tensioning means for the fuse link; a quick releasable clamp for said conductor, comprising a first part arranged to resist the pull of the conductor when the fuse link is tensioned, said part having spaced leg portions forming a space open toward two opposite sides and one end of said part, and a second part pivoted relative to said first part at a point spaced from said open end of said first part and extending in substantial registry with said space,

25. In a fuse device adapted to employ a fuse link of the type having a flexible connection conductor, and said device having means for tensioning such fuse link; means for quick releasably clamping the flexible connection conductor of a tensioned fuse link, comprising a socket element arranged to resist the pull of such connection conductor and having spaced leg portions forming therebetween a conductor receiving socket open toward two opposite sides and one end of said element, thespaced opposed walls of which socket converge so that one of the open sides of the socket is relatively narrower than the other open side of the socket, and a tongue arranged in substantial registry with said socket on the wider open side thereof and pivoted relative to said element at a point spaced from said open end of the element, said tongue and said leg portions of the socket element being arranged to clamp therebetween a tensioned fiexible fuse link connection conductor extending into said socket from the said narrower. open side thereof and looped around said tongue.

RALPH S. BENNETT.

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