US3038048A - Auxiliary circuit interrupter - Google Patents

Description

June 5, 1962 R. J. LANG ETAL AUXILIARY CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed NOV. 28, 1960 604mm J Jean Kazan BY INVENTO 6:44am J [44 6 lrrqzMEX June 5, 1962 R. J. LANG ETAL 3,038,048

-AUXILIARY CIRCUIT INTERRUPTER Filed Nov. 28, 1960 v 2 Sheets-Sheet 2 lrraiwz United States Patent 3,038,048 AUXILIARY CIRCUIT INTERRUPTER Richard J. Lang, Franklin, and Raymond J. Bronikowski, South Milwaukee, Wis., assignors to McGraw-Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Nov. 28, 1960, Ser. No. 72,174 11 Claims. (Cl. 200-120) This invention relates generally to auxiliary circuit interrupters and more particularly to an improved, manually operable, portable circuit interrupter for interrupting load current on fuse cutouts, disconnecting switches and the like.

On occasion it becomes necessary to de-energize a high voltage power line as by moving the fuseholder of a fuse cutout or the switch blade of a disconnecting switch to an open circuit position. If the fuse link in the fuse tube of the cutout has not been previously ruptured, arcing will take place between the fuseholder contacts and the stationary contacts on the fuse support as the fuseholder is moved to an open circuit position. The same condition is experienced in a disconnecting switch between the movable switch blade and the stationary switch contacts as the blade is moved to open circuit position. In both cases, severe burning of the separating contacts may take place thereby seriously hampering or destroying the usefulness of the device.

In addition to the damage suffered by a cutout or switch as a result of uncontrolled arcing there is also the possibility that the uncontrolled arc may flash to ground across the cutout or switch. The resultant fault may cause damage to other equipment on the line, and may seriously injure the lineman who has opened the cutout or switch.

When a fault condition of this nature occurs, an automatic circuit breaker on the source side of the fault may be called upon to clear the fault consequently interrupting service on a large section of the line. In any case a wide variety of damaging effects may be experienced in this type of operation.

Some prior art devices have attempted to correct arcing between live, separating, contacts by means of a portable circuit interrupting device for bypassing the line current around the fuse or switch and thus avoiding arcing when the fuse is removed from the line or when the switch is opened. In these type devices the arc is generally interrupted in the portable circuit interrupting device.

A great disadvantage of this type of portable interrupting device is that the switch or cutout itself must be structurally modified to be capable of combination with the portable tool in that auxiliary contact hooks or the like must be affixed to the cutout or switch. This type of portable device is also limited to use with open type cutouts and switches.

Due to the fact that prior art devices of this type rely on evolving enough gases to extinguish the are it becomes necessary to keep accurate records of the usage of the device to check whether the device is capable of interrupting a particular circuit without additional maintenance. If a device that is incapable of interrupting a given circuit is utilized in an attempt to interrupt a given circuit, considerable burning of the switch or cutout and interrupting device may occur since the interrupting device itself constitutes a portion of the circuit.

Other prior art devices, in attempting to correct the problem of uncontrolled arcing during opening of the cutout or switch, have utilized gas filled cartridges in the fuse cutout itself which, upon opening of the cutout, will spew gases in the general direction of the arc. However, since these cartridges are positioned within the cutout for an indefinite length of time prior to the time the cutout may be opened under load, there is always doubt as to whether the cartridge is in operating condition, or for that matter, whether or not a cartridge had been previously installed in the cutout. This latter condition cannot be readily ascertained by the lineman. An additional disadvantage of these type devices is that the switch or cutout must be specially modified in order to receive the cartridge; a great disadvantage from a cost standpoint and from the point of view of applying this technique to existing circuit interrupting devices.

It is therefore an object of this invention to provide a simple, inexpensive, portable load break (auxiliary circuit interrupter) device that can be used with a wide variety of existing cutouts and switches without prior modification of said cutouts and switches.

Another object of this invention is to provide a manually operable, portable, load break device that extinguishes the arc accompanying opening of a switch or cutout under load, by spewing forth a fluid which serves to elongate and de-ionize the arc at an early current zero.

Another object of this invention is to provide a portable load break device that has a minimum number of moving parts which will be subject to electrical or mechanical malfunction.

A further object of this invention is to provide a portable load break device that has a minimum number of components that need be replaced after operation of the device.

A still further object of some embodiments of this invention is to provide an auxiliary circuit interrupter which is so designed that the angle of the fluid blast relative to the separating contacts of the cutout or switch will remain constant for any angle to which the fuseholder or switch blade is opened.

Other objects and advantages of our invention will be apparent from the following description of the preferred embodiments of the invention taken in connection with the accompanying drawings in which:

FIG. 1 is a partially cutaway view, in side elevation of the invention in conjunction with an open type fuse cutout;

FIG. 2 is a partially cutaway view in side elevation of a slightly modified form of the invention in conjunction with an enclosed fuse cutout;

FIG. 3 is a partially cutaway plan view of another embodiment of the invention;

FIG. 4 is a view of a portion of the device of FIG. 3 taken along line 44; and

FIG. 5 is a partially cutaway view in side elevation of another embodiment of the invention.

Referring now to FIGURE 1 an open type fuse cutout is indicated generally at 10. The fuse cutout is of the standard type and comprises an insulator 11, an upper stationary contact assembly 12 including stationary contacts 13, latch 14 and protective hood 15, a lower fuseholder support 16 rigidly aflixed to insulator 11 and having lower stationary contacts 17 affixed thereto, and a fuseholder assembly 18 including upper and lower contacts 19 and 20 respectively, and a fuse tube 21 containing a rupturable current responsive element (fuse link) 22 therein electrically bridging the upper and lower contacts 19 and 20. As is customary a pull ring mechanism 23 is pivotally mounted on one end of the fuseholder and has a portion thereof normally in contact with latch 14 so that a downward pull on the pull ring serves to impart an upward action to latch 14 thereby allowing the fuseholder to become unlatched and to pivot out of contact bridging position.

It is to be understood at the outset that any one of the embodiments of the invention herein contained may be utilized with a fuse cutout, disconnecting switch or the like; the particular combinations shown being merely for purposes of illustration.

The load break device of this invention is indicated generally as 24 and comprises an elongate insulating rod-like, handle member 25 having a projecting hook member 26 affixed at the upper end thereof which is adapted to engage pull ring 23. A support member 27 is aflixed to the upper extremity of handle 25 as by nut and bolt means 28. In this connection it should be noted that the body of the load break device may be mounted on any conventional hook stick.

The upper end of member 27 has afflxed thereto a wide angle nozzle 29 and a tubular puncturing stud 30 which communicate with one another. Adjacent one end of the puncturing stud in member 27 is a cartridge guide cavity 31 which is adapted to slidably receive a portion of an expendable fluid filled cartridge 32. As can be seen in FIG. 1 the normal position of the cartridge head 32' is in touching relation, or in close proximity to, the puncturing stud 30. Head 32' of cartridge .32 in contact with puncturing stud 30 may be of any sealing material which will break or puncture under relatively small impact or piercing forces and which will normally be strong enough to provide sufficient sealing strength to retain the pressurized fluid in the cartridge.

A substantially L-shaped lever 33 is pivotally mounted on an arm portion 27' of support member 27 by means of pivot pin 34. Lever 33 may have a notched portion 35 on one leg thereof so as to receive one end of expendable cartridge 32. An aperture 36 on the other leg of lever 33 is provided for anchoring a trigger cord 37 thereto. Eyelet means 38 may be affixed to the lower end of handle 25 and cord 37 may be passed therethrough to the lower end of the stick 25.

The pressurized fluid contained in cartridge 32 and in the following cartridges and cylinders (fluid receptacles) to be described may be of any fluid material suitable for extinguishing an are, such as carbon dioxide, compressed air, sulfur hexafluoride, carbon tetrachloride, boric acid, or the like.

In operation (under load) hook member 26 on handle member 25 is engaged with pull ring 23 of cutout 10. Axial pull on handle 25 will cause the fuseholder 18 to pivot about support 16 and contact 19 to move away from upper stationary contact 13 thereby drawing an are between contacts and/or between the latch 14 and the contact 19. If this are is allowed to continue severe burning of portions of the cutout may occur. To extinguish this are before the contacts or other associated portions of the cutout are damaged, a manual pull on cord 37 is initiated causing the lever member 33 to pivot about its pivot pin 34 thereby forcing the puncturable head 32 of expendable cartridge or cylinder 32 against the puncturing stud 30 in the cavity 31 of support 27. In forcing head 32 against stud 30 the cylinder will be punctured or cut, thereby allowing the carbon dioxide or other fluid therewithin to escape therefrom and to pass outwardly through the interior of the stud 30 and through the wide angle nozzle 29. The nozzle 29 serves to direct the escaping fluid toward the arc existing between the upper contact or associated cutout portions thereby causing the arc to be extinguished.

In actual operation the cylinder 32 should preferably be punctured immediately prior to opening of the switch or cutout so that the escaping fluids begin to extinguish the are from its inception. After the switch or cutout is successfully opened the load break device 24 may be disengaged from pull ring 23 and a new cartridge may be inserted in the cavity 31 and the expended cartridge disposed of preparatory to re-using the device.

While the device of FIG. 1 is shown as directing fluid from a position above and to the front of the cutout it is possible to re-position the support 27 around the handl or to move it along the axis of the handle by loosening members 28 so that fluid may be directed from a different position relative to the cutout.

In PEG. 2 a modified form of load break device 40' is shown in conjunction with an enclosed fuse cutout 41 of the type having .an insulated box 42, upper and lower stationary contacts 43 and 44 respectively, a door 45 mounted on the box 42 and pivotable about its base with respect thereto, and a fuse tube 46 including upper and lower contacts 47 and 48 respectively which is mounted on the door and which contains a fuse link (not shown) which normally electrically bridges the contacts 47 and 48. The door 45 of the cutout 41 is provided with an integral pull ring 49 on one end thereof. A downward force exerted on the pull ring 49 serves to pivot the door 45 about its base thusly removing the fuse tube from contact bridging position. v

The load break device 4'9 (auxiliary circuit interrupter) of FIG. 2, like that of FIG. 1, includes a support member 27" having an arm portion 27" at the upper end thereof to which an L-shaped lever 33' having an aperture 36' and a notch is pivoted by means of pivot pin 34'. The device is also similar to that of FIG. 1 in that a trigger cord 37' is anchored to aperture 36' in lever 33 and when actuated, serves to force cartridge head 32" of cartridge 32" against a tubular puncturing stud 30' which extends into guide cavity 31' and which communicates with a wide angle nozde member 29'.

The support member 27" of FIG. 2 is rigidly mounted on member 59 which has a projecting hook portion 51 at its upper end which is adapted to engage the pull ring 49. A handle member 52 having eyelets 38 for the passage therethru of cord 37 is pivotally connected to the other end of member 50 as by means. 53. A torsion spring 54 normally serves to axially align handle 52 and member 50 but is of such a strength that relative motion between handle 52 and member 50 may be accomplished manually. Mounted intermediate the ends of member 27 and above hook portion 51 of member 50 is a projecting stop member 55 which is adapted to bear against the outer face of door when handle 52 and member are axially aligned.

It can be readily seen that when the hook 51 engages pull ring 49 and stop member abuts against door 45 that as the handle 52 is actuated to open the door that the relationship between the nozzle 29', pull ring 49, and the intersection of the stop 55 and door 45 remains constant for any angle to which the cutout door may be opened (as shown by the dotted lines of FIG. 2). Therefore the gases ejected thru the nozzle 29' will blast in one direction relative to the arc, irrespective of the extent of door opening, thereby more efliciently directing gases across the arc and extinguishing same.

After the arc is successfully interrupted the device may be removed from the cutout at which time the torsion spring 54 will realign the handle 52 and member 50. As before all that need be done to prepare the auxiliary circuit interrupter for further duty is to replace the cartriddge 32 in the cavity 31 with a new unruptured cartr1 ge.

Referring now to FIG. 3 there is shown a slightly modified puncturing mechanism which may be used with either of the embodiments of FIG. 1 and 2. The device of FIG. 3 includes a support member 7t) having a wide angle nozzle 71 and a tubular puncturing stud 72 mounted thereon and in communication with the nozzle. Support member '7!) is also provided with fastening means 73 which is adapted to engage a hook stick (not shown) for mounting the device thereon. If the puncturing mechanism of this embodiment is to be incorporated in a device like that of FIG. 2 the fastening means 73 could be rigidly attached to an intermediate member which would then be pivotally mounted on the upper end of a hook stick, but this is not shown. A tubular portion 74 is affixed to support it? and extends at substantially right angles therefrom and has on the free end thereof external screw thread 75. Intermediate the ends of portion 74 is a notched peripheral area 76 which is adapted to receive a U-shaped latch washer 77. The latch washer (FIG. 4) has an aperture 78 therein for anchoring a trigger cord 79 which may be actuated from the other end of the hook stick member. An apertured enclosing member 80 engages screw threads 75 on tubular member 74 and serves as a seat for helical compression spring 81. A movable cylinder engaging member 82 which serves as a seat for the other end of spring 81 is positioned in the bore of member 74 and has a central aperture 82' therein. A fluid containing cylinder member 83 generally similar to the cartridge 32 of FIG. 1 is afiixed at its neck portion 84 to member 82 as by screw threads 85 or similar means. It can thusly be seen that when the cylinder 83 is attached to member 82 that member 82 and the cylinder 83 are biased toward the puncturing stud 72 by the spring 81 but that latch 77 normally prevents motion theretoward.

In operation the hook on the hook stick (not shown) engages the pull ring on the cutout or switch with the wide angle nozzle 71 directed toward the upper stationary and movable contacts of the switch or cutout. A downward pull by the operator on trigger cord 79 will cause latch 77 to disengage from movable member 82, and member 82, under the force of spring 81 will carry the cylinder 83 into engagement with stud 72 which will puncture the cylinder 83 causing the arc extinguishing fluid therewithin to pass through stud 72 and nozzle 71 to the vicinity of the upper switch or cutout contacts. When the handle member is actuated to open the cutout or switch the are drawn between current carrying parts of the cutout will be extinguished by the fluid emitted from cylinder 83 and directed by nozzle 71 before serious contact burning and the like can occur.

After the device has been utilized to open a circuit interrupting device under load, a new cartridge is inserted in member 82 and the member 82 held against the spring tension while latch 77 is replaced in the slot 76. The device is then ready for performing its function again.

In FIG. 5 another embodiment of the invention is shown which may be utilized in conjunction with a switch or cutout and which comprises a tubular, elongate, insulating handle member 86 having within the confines thereof an insulating tubular member 93 which may be of rubber, plastic or other material which will serve as a conduit for are extinguishing fluid. Positioned adjacent the lower end of the handle 86 and rigidly aflixed thereto is an arc extinguishing fluid filled pressurized, manually operable, cylinder 94 having actuating means 95 operably associated therewith. A tubular conduit member 93 is connected between tubing 93 and cylinder 94 so that upon actuation of member 95 fluid will be passed from the cylinder to the tubing. The cylinder 94 is shown as being attached to the member 86 by strap means 96 but any similar affixing means will suffice.

A nozzle support member 88 is pivotally attached to the upper end of hook stick 86 by means of pivot pin 89 and torsion spring 90 which normally serves to align members 86 and 88. The upper end of member 88 is of a curvate configuration and has a tubular passageway 91 therethru which culminates in a wide angle nozzle member 92. A hook member 87 is situated on member 88 and is adapted to engage the pull ring of a cutout or switch. The wide angle nozzle member 92 is shown as being attached to nozzle support 88 although it may be a machined portion thereof if this is desired but this is not shown.

A flexible by-pass tube 97 is attached to members 88 and 86 as by means 98 and communicates with passageway 91 and insulating tubular member 93 thereby serving as a fluid by-pass around the pivotal connection between members 86 and 88.

Intermediate the ends of nozzle support 88 is a projecting stop member 99 which is adapted to normally bear against a portion of the cutout or switch. Since the member 38 is pivotable with respect to the handle 86 and since the stop 99 serves as a positioning fulcrum the nozzle 92 will be in a position to direct gases in the vicinity of the arc irrespective of the degree of opening of the switch or cutout. In the case of tool use with an open fuse cutout or switch the stop 99 may be bifurcated so that it will be prevented from slipping 01f the upper part of the fuse cartridge or switch against which it is biased.

In operation the operator actuates discharge means on cylinder 94 causing arc extinguishing fluids to be expelled from the tank or cylinder. The fluids so expelled pass from the cylinder thru member 93, thence pass upwardly thru tubing 93, by-pass 97, passage way 91 and are emitted from nozzle 92 in the vicinity of the upper contacts of the disconnecting device. The handle member may then be pulled downwardly to cause the fuseholder or switch blade to be moved away from the stationary contacts. Any arcing that would ordinarily take place between contacts is quickly extinguished by the directed gas or fluid blast from nozzle 92.

It can be seen that the efficiency of the arc extinguishing fluids is materially increased by virtue of the fact that the pivotal connection and stop 99 maintain a given angle between the nozzle and the upper contacts so that fluids are emitted in the direct path of the arc regardless of the degree of opening of the fuse cartridge or switch blade.

A pressure indicator 100 may be positioned on the cylinder 94 to indicate the pressure within the cylinder so that when the pressure is insufficient to cause an arc to be extinguished, visual indication of this condition will be readily available to the operator prior to are interrupting attempts. This particular embodiment of the invention has the particular advantage of serving as an auxiliary load break a number of times before maintenance is required since a tank full of arc extinguishing fluid will suflice for a number of current interruptions.

It can thusly be seen that our invention relies on a non-current carrying portable load break tool which requires no prior adaptation of the cutout or switch for use therewith and which never electrically becomes part of the switch or fuse circuit but which relies on fluids emitted from a cylinder to extinguish arcs created in opening a switch or cutout under load. Hence there is no chance of electrical malfunction of the load break tool or of injury occurring to the lineman as a result of the malfunction. Further, since there are very few moving parts in the load break tool of the invention mechanical malfunctions and damage and injury associated therewith are minimized.

The device is especially useful in that a quick visual inspection of the cartridge or cylinder will determine whether the device is capable of opening a particular circuit interrupter or disconnecting device i.e. by looking at the pressure gauge or by checking to see if the cartridge has been punctured. If a pressure gauge is not utilized in conjunction with the cylinder of FIG. 5 it is also conceivable that an indication of cylinder capabilities may be given by the weight thereof.

While four particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that various changes and modifications can be made therefrom without departing from the invention and, therefore, it is intended that the appended claims cover all such changes and modifications as fall within the true spirit and scope of the invention.

We claim:

1. A load break tool for a circuit disconnecting device of the type having a pair of spaced contacts and a contact bridging member movable into and out of electrical bridging engagement with said contacts and including a hook receiving member at one end thereof; said tool comprising an elongate manually operable handle member having a portion thereof adapted to releasably engage said hook receiving member, cylinder support means attached to said handle member and hav ing mounted thereon a cylinder containing an arc extinguishing fluid under pressure, fluid directing means extending beyond one end of said handle member and attached thereto and in communication with said cylinder for directing fluids in the direction of the contacts at one end of said bridging member, and manually operable means for releasing at least a portion of said fluid in said cylinder, whereby opening of said disconnecting device under load is accomplished by a downward axial pull on said handle member while actuating said manually operable means to release are extinguishing fluid from said cylinder to said fluid directing means thereby extinguishing the electrical are drawn between moving current carrying portions of said disconnecting device and minimizing pitting and burning of said portions.

2. A portable load break tool for a circuit disconnecting device having a pair of spaced contacts and a contact bridging member pivoted at its lower end for movement into and out of circuit bridging engagement with said contacts and including a hook receiving member mounted at its free end; said tool comprising, a handle member, a support member afiixed to one end of said handle member, a hook member aflixed to the same end of said handle for engaging said hook receiving member, an arc extinguishing fluid filled, puncturable cylinder mounted on said support member, manually operable puncturing means mounted on said support member for releasing said fluid from said cylinder, fluid directing means in communication with said cylinder and normally directed toward the contacts at the free end of said bridging member, whereby said tool is utilized to impart relative motion to said bridging member with respect to said stationary contacts and the electrical are created by moving said bridging member under load is extinguished by fluids liberated from said cylinder and directed by said fluid directing means into the vicinity of said contacts.

3. A portable load break tool for a disconnecting device of the type having a pair of spaced apart contacts and a bridging member movable into and out of circuit bridging engagement with said contacts and including a hook receiving member mounted at one end thereof; said portable load break tool comprising in combination, handle means, a support member pivotally mounted on one end of said handle means and including a hook member mounted thereon which is engageable with said hook receiving member of said disconnecting device, wherein downward movement of said handle means serves to remove said bridging member from circuit bridging position, said support member having means thereon which normally abuts against a portion of said disconnecting device and a cartridge guide portion, fluid directing means associated with said cartridge guide portion of said support member for directing fluid in the vicinity of the are created upon removal of said circuit bridging member from the circuit under load, a tubular puncturing member mounted on said support member and in communication with said fluid directing means, a fluid filled puncturable cartridge slidably received in said cartridge guide portion of said support member, lever means pivotally mounted on said support means and engaging a portion of said cartridge, means connected to said lever means and operable from the other end of said handle means for causing said lever to urge said cartridge against said puncturing means to liberate fluid from said cartridge and allow same to pass to said fluid directing means thereby enabling the arc created during removal of said bridging member from circuit bridging position to be extinguished, whereby positioning of said fluid directing means relative to the free end of said bridging member is constant irrespective of the degree of movement of said bridging member.

4. A portable auxiliary circuit interrupter for use with a disconnecting device of the type having a pair of spaced stationary contacts and a contact bridging member movable into and out of bridging engagement with said contacts and including a hook receiving member at one end thereof; said interrupter comprising, a manually operable handle member, means pivotally mounted with respect to said handle member for engaging said hook receiving member so that a downward pull on said handle member will cause said bridging member to move out of bridging engagement with said contacts, fluid directing means pivotally mounted with respect to said handle member for directing fluid in the vicinity of the electrical arc created by removal of said bridging member from contact engagement under load, stop means pivotally mounted with respect to said handle member and normally abutting upon a movable portion of said disconnecting device, are extinguishing fluid filled receptacle means for proving a source of fluid to extinguish the electrical are created upon removal of said bridging member from bridging engagement with said contacts, manually operable means for releasing at least a portion of said fluid in said receptacle, and means for conveying said released fluid to said fluid directing means, whereby said fluid directing means, said means for engaging said hook receiving memher and said stop means describe similar arcs upon removal of said bridging member from contact bridging engagement thereby enabling fluid spewed thru said fluid directing means to be directed in the path of the electrical arc irrespective of the degree of pivotal movement of said bridging member.

5. A load break tool for a disconnecting device of the type having a pair of spaced contacts and a contact bridging member pivoted at one end for movement into and out of electrical bridging engagement with said contacts and including a hook receiving member at its free end; said tool comprising means engageable with said hook receiving member for removing said contact bridging member from electrical bridging engagement with said contacts, a fluid receptacle associated with said engage able means, said receptacle being filled with an are extinguishing fluid under pressure, manually operable means associated with said receptacle for discharging fluid there from, and fluid directing means operable to direct fluid in the general direction of the free end of said bridging member, whereby when said engageable means is engaged with said hook receiving member and actuated to disengage the free end of said bridging member from said contacts under load the resultant arc may be extinguished upon manual excitation of said discharge means thereby allowing fluid to pass to the vicinity of said arc.

6. A load break tool as in claim 5 wherein means are provided in conjunction with said fluid directing means for maintaining a constant angle between said fluid directing means and the free end of said contact bridging member irrespective of the degree of pivotal movement of said contact bridging member.

7. A portable auxiliary circuit interrupter for use with a fuse cutout, switch or the like comprising, in combination, a handle member, means attached to said handle member for removing a fuseholder switchblade, or the like from contact bridging position, cartridge support means attached to said handle member, an expendable, arc extinguishing fluid filled, puncturable cartridge supported by said cartridge support means, stationary puncturing means normally spaced apart from said cartridge and mounted on said supporting means, resilient means urging said cylinder into engagement with said stationary puncturing means, releasable latch means mounted on said support member for normally preventing said cylinder from moving into engagement with said stationary puncturing means, manually operable means connected to said latch means and operable to release said latch means thereby permitting said cylinder to impinge upon said stationary puncturing means, and nozzle means mounted on said cartridge supporting means for directing fluids discharged from said cylinder toward the vicinity of the are created upon opening of said cutout, switch or the like under load, whereby upon removal of said tuseholder, switchblade or the like from contact bridging position under load, the resultant arc may be extinguished upon release of said latch means thereby providing fluid to said nozzle means which fluid is directed in the vicinity of the arc to thereby extinguish same.

8. A load break tool for a disconnecting device of the type having spaced apart upper and lower contacts, a movable member pivoted at one end normally electrically bridging said contacts and including a hook receiving member at the free end thereof, said tool comprising in combination an insulating handle member, hook means mounted on one end of said handle member and engageable with said hook receiving member to remove said movable member from electrically bridging position, an arc extinguishing fluid filled receptacle mounted near the other extremity of said handle member, manually operable means for discharging a portion of the contents of said receptacle, tubular means in communication with said cylinder for carrying the discharged fluid from said receptacle to said one end of said handle member, and nozzle means in communication with said tubular means and mounted on said handle member for directing fluids discharged from said cylinder in the vicinity of the electrical are created upon movement of said movable member out of electrically bridging position.

9. A load break tool as in claim 8 wherein means are provided on said receptacle for indicating visually the arc interrupting capabilities of the fluid contained therein.

10. A load break tool as in claim 8 wherein means are provided for maintaining a relatively constant angle between said nozzle means and a portion of said movable member during removal of said movable member from electrical bridging position.

11. A load break tool for a circuit disconnecting de vice of the type having a pair of spaced contacts and a contact bridging member movable into and out of electrical bridging engagement with said contacts and including a hook receiving member at one end thereof; said tool comprising an elongate manually operable handle memher having a portion thereof adapted to releasably engage said hoot receiving member, cylinder support means attached to said handle member and having mounted thereon a cylinder containing an arc extinguishing fluid under pressure, manually operable means for releasing at least a portion of said fluid in said cylinder, said released fluid being eflective to extinguish the arc incident to opening of said circuit disconnecting device, whereby opening of said disconnecting device under load is accomplished by a downward axial pull on said handle member while actuating said manually operable means to release are extinguishing fluid from said cylinder to thereby extinguish the electrical are drawn between moving current carrying portions of said disconnecting device so as to minimize pitting and burning of said portions.

References Cited in the file of this patent UNITED STATES PATENTS

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