US3005891A - Load break device - Google Patents

Description

Oct. 24, 1961 F. J. CHAREWICZ ETAL 3,005,891

LOAD BREAK DEVICE Filed May 1, 1959 3 Sheets-Sheet 1 Oct. 24, 1961 F. J. CHAREWICZ ET AL 3,005,891

LOAD BREAK DEVICE Filed May 1, 1959 3 Sheets-Sheet 2 Oct- 24, 1961 F. J. CHAREWICZ ET AL 3,00

LOAD BREAK DEVICE 3 Sheets-Sheet 3 Filed May 1, 1959 Patented Oct. 24, 1961 3,005,891 LOAD BREAK DEVICE Francis J. Charewic'z, Lanesboro, and Sidney R. Smith, Jr., Stockhridge, Mass, as'signors to General Electric Company, a corporation of New York Filed May 1, 1959, Ser. No. 310,424 9 Claims. (Cl. 200-114) This invention relates to a load break device or auxiliary circuit interrupter for circuit isolators such as fuse cutouts and disconnect switches.

7 It is an object of this invention to provide a load break device or auxiliary circuit interrupter for circuit isolators which is uncomplicated, low cost and reliable.

It is a further object of this invention to provide a load break device .or auxiliary circuit interrupter for circuit isolators in which the load break device will automatically reset itself after it has performed its function.

It is a further object of this invention to provide a load break device wherein its electrical arc interrupting medium does not have to be renewed, recharged or the like. For instance, some prior art load break devices utilized materials which will evolve an electrical arc interrupting gas when an electrical arc is in contact therewith. These materials are eventually eroded whereby they must be renewed, It is the intent of the above stated object to overcome this type of disadvantage.

In our invention the above-mentioned type of disadvantage of prior art load break devices is overcome and the stated objects are fulfilled by incorporating an air puffer type of auxiliary circuit interrupter in the circuit isolating device. Interrupting an electrical arc by an air puffer type principle is not new per se and has been used heretofore in large circuit breakers. However, in our invention the air puffer type auxiliary circuit interrupter is uncomplicated and incorporated into the circuit isolator so that it will automatically reset itself and have very little likelihood of jamming or otherwise failing to operate when it is intended to do so. Inasmuch as the load break operates on air there is no problem of renovating or recharging it. That is to say, it will operate relatively indefinitely without any maintenance.

It was heretofore stated that circuit breakers have used an air puffer type principle of interrupting the electrical arc. The blast of air or other gas for interrupting the electrical arc is conventionally provided from a tank of compressed gas which must be periodically recharged. This disadvantage is not present in our device. Additionally, in circuit breakers the electrical arc has been conventionally interrupted by driving it into a bafile arrangement so as to elongate or sub-divide the electrical are or do both of these things. In our invention, electrical arc interruption is not dependent upon elongation or subdivision of the electrical arc. Rather, the electrical arc is interrupted by continuously wiping or swabbing one of the electrical contacts on which the electrical arc terminates with a blast or jet of air. This continuous swathing or Wiping of the contact with a blast or jet of air continuously removes ionized gases from the point of electrical arc termination as well as ionized gases surrounding the arc itself. This increases the arc voltage necessary to sustain the electrical are so that at first current zero the arc will not re-strike. This is preferably accomplished by directing the blast or jet of air along or around the movable contact in the direction of the electrical arc.

In prior art circuit breakers, the blast of gas has conventionally been directed across the electrical arc whereby electrical arc interruption has been obtained primarily by virtue of elongation of theelectrical arc. This type of electrical arc interruption requires a large space or chamber within which to interrupt the electrical arc and this disadvantage is not true of the auxiliary air putter type circuit interrupter of our invention.

While the Specification concludes with claims particularly pointing out and distinctly claiming the subject matter which we regard as our invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a broken away enlarged top view of the auxiliary circuit interrupter or load break device of FIG. 2,

FIG. 2 is a side elevation view of one form of our invention,

FIG. 3 is a side elevation view of a second form of our invention with the device shown in the closed position,

FIG. 4 is a view similar to that of FIG. 3 with the device shown in the start of its open position,

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 4 with the section being shown in enlarged scale,

FIG. 6 is a perspective view of the bellows compressing element of the second form of the invention,

FIG. 7 is a broken away side elevation view of a third form of our invention with the apparatus shown in the closed position,

FIG. 8 is a view similar to that of FIG. 7 with apparatus in the open position, and

FIG. 9 is a sectional view taken along the line 99 of FIG. 8 with the section being shown to enlarged scale.

Referring now to FIG. 2 of the drawings, the first form of our invention is illustrated in connection with a main circuit isolator or interrupter which is a fuse cutthe out of the open and automatically drop-out type. This is a conventional form of cutout and it comprises an electrical insulator 1 which can be supported from the cross arm of a line pole or the like by virtue of a strap 2 which is connected to a central portion of the insulator 1 by a band 3. The insulator 1 has a fuse holder assembly 4 pivotally mounted thereon, although it will be appreciated by those skilled in the art that a' disconnecting blade can be substituted for the fuse holder assembly 4 as the switch element of the circuit isolator. The fuse holder assembly 4 comprises an electrical insulating material fuse tube or holder 5 which is closed at its upper end by a contact cap 6. The upper end of the insulator 1 carries a contact latch 7 which cooperates with the contact cap 6 to latch the fuse holder assembly 4 closed. A line terminal 8 is electrically connected to the contact latch 7,

The lower end of the fuse holder 5 is pivotally connected to the lower end of the insulator 1 by virtue of a generally L-shaped element 9 which has its trunnions 10 pivoted in the pivot grooves 11 of a hinge element 12 which is supported from the lower end of the insulator 1. The upper end of the element 9 is pivotally connected to the fuse tube 5 by a clamping element 13. The hinge element 12 has an electrical line terminal 14 and a'contact 15 which makes electrical engagement with a contact portion 16 of the element 9. A fuse link whose details are not illustrated is disposed in the fuse tube 5 and it extends from the fuse holder cap 6 to out of the open bottom end of the fuse tube 5. The lower braided end 17 of the fuse link is tautly fastened to a'thumb screw 18 or the like on the element 9.

The fuse cutout can be used to protect electrical apparatus by connecting a sourceof electrical energy to the' terminal 8 and a lead to the electrical apparatus from terminal 14. In its energized condition theelectrical circuit extends from terminal 8 to contact latch 7 and contact cap 6, then through the fuse link to contacts 16 and 15 to terminal 14. When an over-current occurs in the electrical circuit the fusible portion of the fuse link will melt and therefore the element 9 will no longer be held against the fuse tube 5 by the fuse link. Therefore, parts 5 and 9 will be free to pivot with respect to each other. The weight of the fuse holder assembly 4 causes the assembly to move down slightly to unlatch the contact cap 6 from with respect to the contact latch 7 and thereafter the fuse holder assembly is free to pivot in a right hand direction to a down position whereby it hangs downwardly from the element 12.

Sometimes it is desirable to electrically isolate the electrical apparatus which is being protected by the fuse cutout from the source of electrical energy. For instance, one may want to do this to perform maintenance work on the protected electrical apparatus. This can be accomplished by manually opening the fuse cutout. For this purpose an eyelet handle is provided on the fuse holder. The hook of a not shown conventional switch stick can be inserted into the eye of handle 20 to pull the fuse holder assembly open. However, when this procedure is followed for manually breaking the load, a heavy electrical arc may be drawn between the separable contact elements 6 and 7. This are may persist even if the fuse holder assembly is pulled to full-open position. This are is a reat to the safety of the linemen and has a corrosive effact on the cutout. Also, a short circuit to ground can result if a high wind whips the electrical are into contact with a grounded element.

It is the purpose of the air puffer type of auxiliary circuit interrupter or load break device shown positioned above the contact latch 7 to enable one to break the load without appreciable arcing at the cutout. Although the load break device is illustrated as being positioned slightly above the contact latch 7 it will be appreciated by those skilled in the art that it could be positioned along either side of the contact latch 7 in the event it is desired to re duce the over-all height of the illustrated assembly. The load break device is supported on the cutout by virtue of an electrical insulating material bracket which is mounted on the upper end of the insulator body 1.

Referring now also to FIG. 1, a stationary electrical contact 26 of the load break device is electrically connected to the electrical terminal 8. A conducting rod 27 is supported from the right-hand end of the bracket 25, and the left-hand end of conducting rod 27 has a piston 28. The piston 28 is positioned in a movable electrical insulating material cylinder 29. The front of the cylinder 29 is constructed from electrical insulation 3%, and in the front of the cylinder 29 is mounted a movable contact 31. Electrical insulating material is used for the front of the cylinder 29 and the cylinder itself so as to insure that the electrical arc will actually terminate on the contact 31.

The cylinder 29 is urged in a left-hand or reset direction by a spring 32 which is disposed between the righthand ends of cylinder 29 and bracket 25. The cylinder 29 can be pulled to the right with the hook of a conventional switch stick by virtue of a split pull ring 33 which is con-- nected to the cylinder 29 by a pair of conductors 34.

When the hook of a conventional switch stick is inserted in the pull ring 33 and simultaneously in the eye of handle 20 the load break device is placed in shunt with the separable contact parts 6 and 7 of the main circuit interrupter. The eyelet handle 20 is made from conducting material and is in electrical contact with the fuse holder cap 6 by virtue of a spring 35 which is placed about the fuse tube 5 between the eyelet handle 20 and fuse holder cap 6. This spring is a conventional element in fuse holder assemblies so as to eliminate radio noise and tracking along the fuse holder 5 between contact cap 6 and eyelet handle 20. The movable contact 31 of the load break device is electrically connected to the conducting rod 27 by a braided conductor 36. The conductors 34 are electrically connected to the conducting rod 27 by passing them through a pair of holes 37 formed in a conducting element 38 which is electrically connected to the righthand end of conducting rod 27. Of course the conductors 34 are free to move in holes 37 while still making electrical contact with element 38. Thus, the electrical circuit in shunt with the conducting parts 6 and 7 comprises the contacts 26 and 31, conductor 36, conducting rod 27, conducting element 38, conductors 34 and pull ring 33 which is placed in electrical contact with eyelet handle 29 by a conventional switch stick.

When the conducting parts 6 and 7 are separated an electrical arc will not be established therebetween inasmuch as during separation of parts 6 and 7 contacts 2.6 and 31, which are shunt arcing contacts, remain closed to establish a shunt around separated parts 6 and '7. Further movement of the eyelet handle 20 with a conventionl switch stick carries the pull ring 33 with it and causes the conductors 34 to pull the cylinder 29 to the right. Rightward movement of cylinder 29 causes contact 31 to leave contact 26 and compression of the air within the forward end of cylinder 29.

The contact 31, which is in tie form of a small rod or pin, is carried by a spider 39 or the like and protrudes through the insulating material 39 by virtue of an aperture formed therein which is slightly larger than the pin 31. The spider 39 is 'apert ured by the holes 41. Therefore, the atmosphere which is compressed within the cylinder 29 is forced in a blast or jet along the pin 31 in the direction of the electrical arc. This means that the pin 31 as well as the electrical arc is continuously wiped or swabbed with compressed air. Accordingly, ionized gases at the termination of the electrical arc on pin 31 as well as from the electrical arc itself are continuously being removed. This increases the arc voltage necessary to sustain the electrical arc whereby the electrical arc will be extinguished at first alternating current zero. Further outward movement of the pull ring 33 eventually compresses the spring 32 sufficiently whereby enough resistance is presented to further outward movement of the cylinder 29 so that pull ring 33 snaps oil the hook of the switch stick inasmuch as the pull ring 33 is split and formed somewhat resiliently. Compression of spring 32 means that the cylinder 29 will immediately be urged back in the lefthand position after the pull ring 33 is free whereby the load break device is automatically reset. The right-hand end of the cylinder 29 is apertured as at 42 so that there is no resistance to left-hand movement of cylinder 29 once the pull ring 33 snaps free of the switch stick.

It will now be seen that the load break device is low cost and reliable inasmuch as it has relatively few parts which have almost no likelihood of sticking or jamming. The device is also low cost inasmuch as it operates on air, which is free, and has a relatively indefinite life inasmuch as it does not require any renovation or recharging. Additionally, in the event of the highly remote and unlikely circumstance that the load break device would fail to interrupt the load, the load break device does not interfere with rapid reclosing of the main circuit isolator. That is to say, the fuse holder assembly 4 can be rapidly reclosed with the switch stick merely by pushing the fuse holder 4 towards its contact latch 7. Also, malfunctioning of the load break device will not result in welding or freezing of any of the parts in an open position whereby the circuit cannot be reclosed.

Referring now to FIGURES 3 to 6, this sheet of drawing illustrates a second form of our invention wherein the air puffer load break device is mounted adjacent to the lower end of the cutout and utilizes a bellows type compressor instead of a piston and cylinder arrangement as in the first form of the invention. In the second form of the invention the illustrated open type automatically drop out fuse cutout is similar in construction and operation to that shown in the first form of invention so it will not be re-described. The clamp 13' which performs a function similar to that of clamp 13 of FIGURE 2 performs the additional function of serving as a mounting means for a bellows type compressor 5t Compressor 50 is mounted on the righthand side of the fuse holder assembly 4 and a conduit 51 extends therefrom to a conduit 52 which in turn is connected to a conduit 53 which terminates adjacent to the fuse holder cap 6. The conduit 53 is made from electrical conducting material whereas conduit 52 is constructed from electrical insulating material so that a short circuit is not formed around the fuse within the fuse tube 5. The conducting tube 53 terminates slightly in front of the contact cap of the fuse tube so that it is the point of last electrical contact between the contact latch 7 and the upper end of the fuse holder assembly. Tube 53 is in electrical contact with the contact cap as by welding it to the eyelet handle 20 or the like. When the fuse holder assembly is opened as illustrated in FIG. 4 the part 53 is the point of last electrical contact between the contact latch 7 and the upper end of the fuse holder assembly. Therefore, part 53 and contact latch 7 in effect provide a shunt around the gap between the contact latch and the contact cap which otherwise would have an electrical are established therebetween in the absence of element 53. That is to say, contact latch 7 is a main contact of the main interrupter and also an arcing contact of the shunt arcing contact means of the load break device, and the tube 53 is the other arcing contact of theshunt arcing contact means.

A bellows compressor element 54 which may be generally U-shaped and slanted slightly in a downward direction is connected to the lower end of the insulator body 1 of the cutout. It has a pair of legs 54 which have end portions 54" which are bowed slightly toward each other. Preferably the legs 54' of element 54 are somewhat resilient for a purpose to be described hereinafter. When the fuse holder assembly is pulled open the bowed-in portions 54" will engage an end plate 55 of the bellows 50 whereby bellows 50 will be compressed. Compression of bellows 50 results in a blast of gas through part 53 in the direction of the electrical arc between part 53 and the contact latch 7. This means that the point at which the electrical arc terminates on part 53 as well as the elcctrical'arc itself is swabbed or wiped with compressed air whereby the ionized gases are continuously removed from the .point of electrical arc termination as well as the electrical arc itself. This mcreases the arc voltage necessary to sustain the electrical arc whereby it is extinguished and does not re-strike at current zero.

The spacing between bowed-in portions 54" is not close enough to permit these parts to engage the compressor 50 itself or the adjacent parts of the fuse holder assembly. This is to prevent wear on the compressor 50 and prevent the part 54 from prohibiting the fuse holder assembly todro'p to full-open position once the plate 55 is forced beyond bowed-in portions 54". Plate 55 willppass beyond bowed-in portions 54" after the bellows 56 is sufficiently compressed inasmuch as the legs of element 54 are provided with the correct amount of resiliency to permit this to happen. A spring 56 inside bellowsStlre-expands bellows 50 once plate 55 rides past bowed-in portions 54 so that the air-puffer load break device is automatically reset. However, spring 56 is not absolutely necessary for this purpose inasmuch as when the fuse holder assembly is re-closed the bowedin portions 54" will engage the plate 55 to also expand bellows compressor 50.

The legs 54K of element 54 are spaced from each other sufficiently so that these portions are free and clear of the bellows compressor and the parts of the fuse holder assembly contiguous thereto. Therefore, when the cutout operates as an automatic circuit interrupter, that is to say when the fuse link melts, the part 54 does not prohibit the fuse holder assembly from moving down slightly and then automatically pivoting to the right to full drop out position. It will be appreciated by those skilled in the art that this form of the invention can likewise be used with a disconnecting blade. That is to say, a solid switch blade can be substituted for the fuse tube of the second form of the invention and perform the function of a switch member in the circuit isolator.

Referring now to FIGS. 7-9, illustrated therein is a third form of the invention. This form of the invention illustrates our invention incorporated in a fuse cutout of the enclosed type. The cutout illustrated is of the nondropout type, but it will be obvious to those skilled in the art that the invention is also applicable to enclosed fuse cutouts of the automatically dropout type.

The form of enclosed fuse cutout illustrated in FIGS. 7-9 is well known and therefore will not be described in great detail. Generally speaking it comprises a rec tangular box-shaped insulator housing 60 which is closed by a door 61. The door 61 has a fuse holder assembly 62 mounted thereon. Mounted on the rear surface of insulator housing 60 are upper and lower terminal and contact assemblies 63, 64 and 65, 66 respectively. The fuse tube 67 of the fuse holder assembly 62 has upper and lower contacts 68 and 69 respectively which are adapted to engage the contacts 64 and 66 respectively when the door is pivoted closed. The door is pivotally connected with respect to the insulator body 60 by virtue of a hinge element 76 which is hinged on pivot means 71 which is mounted in the bottom of the housing 66.

In this form of cutout apertures are conventionally formed in the side walls of the housing 60 for the insertion of electrical leads for connection to the terminals 63 and 65. A fuse link 72 is positioned in the fuse tube 67 and the electrical circuit between terminal 63 and 65 comprises contacts 64 and 68, fuse link 72, hinge element 70 and contact 69, and then contact 66. The lower end of fuse link 72 is electrically connected to hinge element 70 at a thumb screw 73. The hinge 7t and contact 69 are in electrical contact with each other by virtue of an electrically conductive strap 74, or these two elements can be integrally formed. The door 61 can be pivoted open mm a conventional switch stick by virtue of handle means 75 formed on the exterior of the door. When the door is moved to closed position it is held latched in the closed position by two co-operative latch members 76 and 77 connected respectively to the rear of housing 60 and the door 61. The fuse holder assembly 62 is mounted on the inside of door 61 in a manner which will be obvious to those skilled in the art, and the cutout can be supported from the cross-arm of a line pole or the like by a strap 78 or the like which is connected to housing 6.0.

The upper portion of door 61 has a chamber 80 formed therein which is adapted to receive part of the load-break device which is positioned in the upper portion of the cutout housing. The load break device illustrated in this form of the invention is similar to the one illustrated in FIG. 1. It comprises an electrical insulating material support 81 which is mounted in the upper end of the cutout housing. Insulating material support 81 has a stationary arcing contact 82 supported thereon which is in, electrical contact with the terminal contact assembly 63, 64. Insulating member 81 also supports a rod 83 which has a piston 84 thereon which works in an electrically conductive cylinder 85.

The front end of cylinder 85 is constructed from electrical insulating material 86 and protruding therefrom is pin 87 which serves as a movable arcing contact. Pin 87 is mounted in and in electrical contact with cylinder 85 by virtue of an apertured conducting spider and pro trudes through a slightly enlarged aperture formed in insulating material 86 in a manner similar to that described in connection with the first form of the invention.

The cylinder 85 is urged in a left hand direction by a spring 88. Cylinder $5 is moved in a right hand direction to separate shunt arcing contacts 82 and 87 and compress gas for wiping the movable contact 87 by an electrically conductive member 89 which can have a U-shaped form as illustrated in the drawing, The righthand bite or bridge portion of U-shaped member 89 is connected to door 61 and is placed in electrical contact with the upper fuse tube contact 68 by a conductor 90.

The left hand ends 8? of the member 89 are bowed slightly towards each other and are adapted to engage a flange 91 formed on the rear of the cylinder 85. In the closed position of the device illustrated in FIG. 7 the bowed-in portions 89 will be positioned to the left of the flange 91. The legs of member 89 can slide along the flange 91. The shunt electrical circuit around contact elements 64, 68 of the cutout comprises contacts 82, 87, the supporting spider for pin 87, cylinder 85, flange 91, part 89, and conductor 9h.

When the door is pulled open the contacts 64, 68 will open first and then after the legs of part 89 have slid along the flange 91 for bowed-in portions 89 to engage flange 91 the contacts 82, 87 will separate. 'Of course, the door is pulled open with the switch stick rather quickly so that when bowed-in parts $9 engage flange 91 the cylinder 85 will be moved rapidly to the right to compress air and wipe the pin 87 and the arc itself with compressed air. This will put out the are between contacts 82 and 87.

Since the legs of part 89 are somewhat resilient the bowed-in portions 89 will eventually ride off the flange 91 after which the door and its fuse assembly is free to drop to the full open position. Movement of the cylinder 85 to the right compresses spring 8% so that the load break device is automatically reset. However, the spring 88 can be omitted and resetting be accomplished when bowed-in parts 89' re-engage flange 91 when the door is re-closed.

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

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

1. In combination, a switch having manully separable conducting parts normally carrying line current and an auxiliary circuit interrupter for interrupting line current, said auxiliary circuit interrupter being mounted on said switch and having separable arcing contact means, said auxiliary circuit interrupter normally being electrically connected to only one side of said switch, means for electrically connecting said switch and auxiliary circuit interrupter in shunt and then opening said switch and then said auxiliary circuit interrupter, means mounted on said switch for compressing air and directing the same on said arcing contact means, and manual operating means for actuating all of said means in a single manual operation.

2. in combination, a manually operable circuit isolating device, such as an open or enclosed type disconnecting fuse, disconnecting switch, or the like, having separable energized conducting parts normally carrying line current, separable arcing contact means mounted on said circuit isolating device for interrupting line current when said conducting parts are manually separated, said arcing contact means being normally electrically connected to only one side of said circuit isolating device, means mounted on said circuit isolating device for compressing air and directing the same on said arcing contact means, means for electrically connecting said arcing contact means in shunt with said conducting parts and then separating said conducting parts and then said arcing contact means and then actuating said air compressing means, and manual operating means for actuating all of said means in a single manual operation.

3. In combination, a manually operable switch and an air putter type load break device therefor, said load break device being mounted on said switch, said switch comprising a pair of electrical terminals which are spaced and electrically insulated with respect to each other, a switch member electrically connected to one of said terminals and a switch member latch electrically connected to the other one of said terminals, a handle for manually operating said switch member with a switch stick, said load break device comprising a pair of separable shunt arcing contacts, means for compressing air and wiping with a puff of compressed air either of said contacts, one of said contacts being mechanically and electrically connected to the terminal to which the switch member latch is connected, and means comprising said handle for electrically connecting the other contact to said switch member and unlatching said switch member with a single switch stick operation and then separating said contacts and operating said air compressing and wiping means.

4. In the combination of claim 3, wherein said switch member is an automatically operable dropout fuseholder, said fuseholder being disposed in a generally upright position, a generally upright and elongated electrical insulator body for supporting said terminals and fuseholder, said latch and the terminal to which it is connected being supported on the upper end of said insulator body, the other terminal being supported on the lower end of the insulator body, and the fuseholder being pivotally supported at its lower end on the lower end of the insulator body, and the upper end of the fuseholder adapted for engagement with said latch.

5. In the combination of claim 4 wherein said switch is an open type fuse cutout in which said insulator body for said fuseholder and terminals is a column type electrical insulator, said air puffer type load break device being supported on a frame which is mounted on the upper end of said insulator above said latch, and said last mentioned means also comprising a flexible connector which is connected to said load break device and has a releasable hook ring which can be engaged with a switch stick for connection with said handle.

6. In combination, a manually operable switch and an air puffer type load break device therefor, said switch comprising a pair of electrical terminals which are spaced and electrically insulated with respect to each other, a switch member electrically connected to one of said terminals and a switch member contact means electrically connected to the other one of said terminals, a handle for manually operating said switch member with a switch stick, said load break device comprising a pair of separable shunt arcing contacts, means for compressing air and wiping with a puff of compressed air either of said contacts, means electrically connecting one of said contacts to the terminal to which said switch member contact is connected, means electrically connecting the other of said contacts to said switch member, and said air puffer type loadbreak device being supported on a frame which is mounted on the upper end of said switch and comprises a cylinder and piston device whereby the operation of said switch member through said handle with a switch stick first separates the switch member from said switch member contact, then separates said separable shunt arcing contacts and operates said air compressing and wiping means to wipe either of said separable shunt arcing contacts with a puff of compressed air, and means for resetting said load break device after opening of said shunt arcing contacts and operation of said load break device.

7. The combination of claim 6 wherein said switch comprises an enclosed cutout having a generally rectangular shaped insulator housing, said switch member is a. fuseholder mounted on a door, said door being pivotally mounted at the lower end of said housing and said handle is mounted on the outside of said door.

8. In combination, a manually operable and automatically operable fuse cutout comprising a dropout fuseholder, said fuseholder being disposed in a generally upright position, a generally upright and elongated electrical insulator body for supporting a pair of electrical terminals at opposite ends of said elongated electrical insulator body, a latch member being connected to one of said terminals which is on the upper end of said insulator body, a fuseholder being pivotally supported at its lower end on the lower end of the insulator body, means providing an electrical connection between the terminal on the lower end of said insulator body and said fuseholder, and an air pufier type loadbreak device, said loadbreak device mounted on said cutout and comprising a pair of separable shunt arcing contacts, and means for compressing air and wiping with a pufi of compressed air either of said contacts, means for electrically connecting one of said contacts to the terminal to which the latch member is connected, means for electrically connecting the other of saidscontact to the upper portion of said fuseholder, the upper end of said fuseholder adapted for engagement with said latch and means comprising said handle for unlatching said fuseholder with a single switch stick operation and then separating said contacts and operating said air compressing and wiping means.

9. The combination of claim 8 wherein said loadbreak device comprising an air compressing and wiping means comprised of a bellows which is mounted on said fuseholder adjacent the lower end thereof, an electrically insulated conduit extending along said fuseholder from said bellows to adjacent the upper end of said fuseholder and means supported by the lower end of said insulator body for compressing said bellows when said fuseholder is manually opened.

References Cited in the file of this patent UNITED STATES PATENTS 908,692 Norland Jan. 5, 1909 2,353,528 Triplett July 11, 1944 2,491,964 Frink Dec. 20, 1949 2,816,985 Lindell Dec. 17, 1957 2,905,789 Earle Sept. 22-, 1959 FOREIGN PATENTS 734,217 Great Britain July 27, 1955 808,772 Great Britain Feb. 11, 1959 1,144,785 France Apr. 29, 1957

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