US2890313A - Switch stick mounted load break - Google Patents

Description

June 9, 1959 s. R. SMITH, JR., ET AL 2,890,313

SWITCH STICK MOUNTED LOAD BREAK Filed Oct. 11, 1957 I5 Sheets-Sheet 1 June 9, 1959 s. R. SMITH, JR., EIAL 2,890,313

SWITCH s'rxcx MOUNTED LOADBREAK Filed Oct. 11, 1957 3 Sheets-Sheet 2 June 9, 1959 s. R. SMITH, JR., ETAL ,8 ,3

SWITCH STICK MOUNTED LOAD BREAK Filed Oct. 11, 1957 3 Sheets-Sheet 3 5' I nfim ors,

idne Rsmifhafm Franc? d. C'fzqr'ewicz, 5 7M P. w

United States Patent SWIT'CH STI'CK- MOUNTED LOAD BREAK Sidney R. Smith, Jr., Stockbridge, and. Francis J. 'Charewicz, Lanesboro, Mass, assignors to General Electric Company, a corporation of New York Application October 11, 1957, Serial No. 689,724

13 Claims. (Cl. 200-148) This invention relates to aswitch stick mounted load break, and more particularly, to a switch stick mounted load break device for circuit interrupters such as opentype' disconnect switches and open-type cutouts.

The instant patent application is a continuation-in-part of our copending patent application, Serial No. 609,219, which was filed on September 11, 1956, now Patent No. 2,834,856, and which is assigned to the same assignee as the instant patent application.

Switch stick mounted load break devices are not new per se. However, prior art switch stick mounted load break devices have several disadvantages, and it is an object of this invention to provide an improved switch stick mounted load break device which will overcome these disadvantages.

One disadvantage of prior art switch stick mounted load break devices is that they tend to be complicated in that they utilize a large number of parts. This means that the devices are not lightweight and low cost. Additionally, the devices are more apt to stick or jam due to the large number of moving parts.

Another disadvantage of prior art switch stick mounted load break devices is that they require some modification in conventional switches or cutouts before they can be used.

A further disadvantage of prior art switch stick mounted load break devices is that the switchor cutout with which the load break device is being used cannot be reclosed in the event the load break device malfunctions. For instance, in one prior art form of switchstick mounted load break device it is possible for the contacts of the load break device to become welded together or for the operating device to become jammed after the load break device has been expanded in order to open the switch or contact and at this stage the switch or cutout cannot be reclosed.

In our invention we overcome the above discussed disadvantages by providing a switch stick mounted load break device which has a minimum number of parts whereby the device is both lightweight and low cost. Additionally, the device has a minimum number of moving parts whereby there is very little chance for the load break device to stick or jam. The loadbreak device can be used with a large variety of existing open-type switches or cutouts without requiring any modification inthe switches or cutouts. Additionally, due to the uncomplicated nature of the load break device and the arrangement of the various parts, the cutout or switch can be readily reclosed in the event the load Ibreak device fails to interrupt the electrical arc.

Broadly, our invention comprises an expendable and replaceable electrical arc extinguishing member which is mounted on the endof a switch stick. The expendable and replaceable electrical arc extinguishing member may comprise a fluid pressure blast generating cartridge or a fuse cartridge such as disclosed in copending' Smith and Carpenter patent application- Serial Number 78,9 95 filed-- Fatented June 9, 1959 April 18; 1956, now Patent 2,834,855, and assigned to thesame assignee as-t-he instant patent application, and our heretofore mentioned copending patent application. The fluid pressure blastgenerating cartridges may utilize compressed gas, gun powderor a chemical substance which will generate gasesand' liquids under-pressure. The fuse cartridges may be used to interrupt the circuit merely by melting ofthe fusible-element.

The features of our invention which we believe to be novel are set forth with particularity in the appended claims. Our invention itself, however, both asto its organization and method of operation, together. with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings.

In the drawings, Fig. 1 is. an elevation. view of. one form of our invention. Fig. 2 is atop View when looking in thedirection of arrow 2 of Fig. 1'. Fig. 3 is atop view of the switch stick mounted load break device of Fig. 1". Fig. 4 is a side view of the switch. stick mounted load'break device when looking in the direction of arrow 4"- of Fig. 3. Fig. 5 is another side view of. the switch stick mounted load break device when looking. in. the direction of arrow 5 of Fig. 4. Fig. 6 is atop view of another form ofswitch stick mounted load break device. Fig. 7 is aside view when looking in the direction of arrow 7 of Fig. 6". Fig. 8- is a top view of another form of switch stick mounted load break device. Fig. 9 is aside view when. looking in the direction of arrow 9 'of Fig. 8. Fig. 10 is a side view of another form of oun'inve'nti'ona Fig. 1:1. is another side view of the switch stick mounted. load break device of Fig. 10 when looking; in the. direction of arrow 11 of Fig. 10. Fig. 12 is anelevation view of another form of switch stick mounted loadbreak device.

Referring. now particularly to Fig. 1, illustratedtherein is a con'ventionalformof.open-type fused cutout. This form of circuit interrupter is particularly described inconstructionand operationin Strobel Patent 2,685,013 issued July 27, 1954 and assigned to the same assignee as the instant invention.

Generally speaking, the circuit interrupter comprises an elongated electrical insulator 1 having a fuseholder 2. mounted thereon. The upper end of the insulator has a latch. element 3 whichalso serves the purpose of a contact, and the lower end of the insulator has a hinge element 4 which also serves the purpose of a contact. The fuseholder 2 spans the latch 3 and hinge 4 to complete an electrical circuit therebetween. The circuit interrupter' is. adapted to be suspended. from the crossarm of a not shown line pole by virtue of a mounting strap 61 which is connected to the central portion. of the insulator by a clamping band 5. The contact latch 3- is provided with a line terminal 7 and combination hinge and contact 4. is provided with a line terminal 8. The circuit interrupter is adapted to protect an electrical apparatus such as a not shown line pole mounted transformer by connecting the terminal 7 to the distribution line and the transformer to the terminal 8. If an overcurrent should develop in the protected transformer a fuse link 9 in fuseholder 2 will melt which will permit the fuseholder to unlatch itself from the latch 3 and drop open, said overcurrent being interrupted in the fuseholder 2 by expulsion. action.

The fuse assembly makes electrical contact at its upper end with contact latch 3 by virtue of a contact cap 11. At its lower end the fuse assembly is provided with a generally L-shaped member 12 which is hinged at its upper end to the fuseholder at the pivot point 13, and its lower left-hand end to the hinge element 4 by virtue of a pair of trunnions 14 which fit in a pair .of bearing grooves 15 formed in the hinge element 4. The fuse link 9 is brought out of the lower open end of the fuse holder of the fuse assembly and is tautly fastened to the member 12. The fuseholder and member 12 comprise a toggle which is released when the fuse link 9 melts whereby the fuse assembly can move downwardly to unlatch itself and then drop open.

The fuseholder, which is a switch member as well as an overcurrent interrupting means, is provided at its upper end with an eyelet handle 16 which is electrically connected to the contact cap 11 by means such as a spring 10. In other conventional forms of this type of circuit interrupter the handle 16 may be integrally formed with the contact cap 11. These parts are usually electrically interconnected so as to prohibit carbon tracking along the fuseholder between the elements 11 and 16 and also to prohibit the formation of corona at the handle 16 and resultant radio interference noise.

The switch stick 20 minus the load break device which is mounted thereon is conventional. That is, it comprises a long electrically insulated pole which can be made from wood or the like. On its upper end it has a cap 18 which is provided with a hook 21 which is adapted to engage the eye of the handle 16. Within certain limits of load current and power factor the load can be manually broken by swinging the fuse assembly open with the switch stick. When this is done, an electrical arc may be established between the contact latch 3 and the contact cap 11. When the load current is high enough and the power factor low enough this electrical arc may not go out even though the fuse assembly is swung to the full open position. This electrical arc has a deleterious effect on the various parts of the circuit interrupter and is a threat to the safety of the lineman and may result in an outage. For instance, a sudden gust of wind may blow the arc into the lineman or into a grounded element. The load break device provides a positive means for rapid extinction of the load current are even though the load power factor is low and the current magnitude is as high as the continuous current rating of the cutout, thus minimizing these hazards.

The load break device comprises an expendable and replaceable electrical arc extinguishing or interrupting cartridge member 22 which is held by a cartridge holder 23 which in turn is carried by an arm 17 which is resiliently mounted on the cap 18 of the switch stick 20. For instance, the cartridge 22 may comprise a small capsule of compressed electrical arc extinguishing gas such as carbon dioxide. The cartridge 22 may be provided with a thin walled tip 24 which will be burned through when an electrical arc terminates thereon. A pivot pin 25 may be provided on the cap 18 for resiliently and pivotly mounting the arm 17. The arm 17 is resiliently biased to the Fig. 4 position by a spring 19 which surrounds the pin 25 and at its opposite ends bears against the arm 17 and the cap 18.

The arm 17 is not biased by the spring 19 beyond the Fig. 4 position by virtue of a stop 26 formed on the arm 17. The switch stick mounted load break device is used by first holding it in an upright position and engaging the hook 21 with the eyelet handle 16. Then the operator can back off slightly from the circuit interrupter which will place the switch stick 20 in a more or less diagonal position and rotate the arm 17 in a clockwise direction whereby the spring 19 is tensioned. Of course, the spring 19 tends to continuously urge the arm 17 back to its idle position indicated in Fig. 4. This means that during the manual load break operation the parts 17, 23, 22 and 24 are successively engaged with the contact latch 17. Accordingly, the tip 24 will be the last point of electrical contact between the fuse assembly and the contact latch 3 whereby the electrical arc will terminate on the tip 24. When an electrical arc plays on the tip 24 it is punctured whereby the compressed gas therein is released to cool and deionize the electrical arc.

The gas blast for extinguishing the electrical arc does not necessarily have to be initiated electrically by having the electrical arc terminate on the tip 24. For instance, the gas blast could be initiated mechanically. This could be accomplished by making the tip 24 frangible enough so that when it rides along the forward edge of the contact latch 3 it is mechanically broken to release the compressed gas from within the cartridge into the electrical arc.

As indicated in Fig. 4 in its idle position the arm 17 extends in a direction which is generally parallel to the lengthwise axis of the stick 20, and then it is curved in a direction which is generally transverse to the axis of the stick. This is so that the parts 17, 23 and 22 will be disposed above the contact latch 3 as indicated in Figs. 1 and 2 and ride along the forward edge of the contact 3. It is also possible to have these parts ride along the undersurface of the contact latch 3 or along a side edge of the latch 3. A side edge acting load break device is illustrated in Figs. 8 and 9. A switch stick mounted load break device whose elements ride along the underside of the latch 3 is not preferred since one which rides along the front or side edges of the latch 3 is less apt to interfere with quick reclosure of the switch in the event the load break device malfunctions. Malfunctioning of the load break device could be caused by a defective cartridge. There is very little chance of mal functioning of the device due to the other load break parts inasmuch as only a single movable part 17 is utilized which means that the load break device will not be apt to malfunction due to sticking or jamming of the parts. However, if the load break device does malfunction it will not interfere with quick reclosure of the switch member. Reclosure of the switch member can be accomplished by quickly moving the switch stick to a vertical position so that the elements 17, 23 and 22 do not catch under the latch 3 and then pushing upwardly to slam the switch member 2 closed.

The circuit interrupter is an automatically operable fused protector which is utilized in distribution systems to provide protection for electrical apparatus which is on a branch or section of a main distribution line. However, the invention is not restricted in its applicability to automatically operable switches or fused switches. For instance, the switch member 2 could comprise a plain disconnect switch blade or knife. All known commercial forms of such switches utilize an eyelet handle similar to the element 16 and a contact latch similar to the element 3. Therefore, the load break device of the instant invention is believed to have substantially universal application without requiring any modification in distribution system switches which are presently available on the market.

Without the load break device when the switch member 2 is opened with a conventional switch stick an arc would be drawn between the latch 3 and the switch memher 2. These types of distribution system switches ordinarily are not designed or intended to be used as manual load break devices. Therefore, the electrical arc may not go out even though switch member 2 is moved to the fully opened position. Accordingly, in order to disconnect the electrical apparatus from the energized line it may be necessary for the lineman or operator to open a main breaker back in the main line. Of course, this results in a service interruption on all branches of the main line. Our invention overcomes this disadvantage by providing an effective manual load break device for the branch protector or switch whereby a main breaker need not be relied upon to interrupt a branch or section of the main line.

The switch stick mounted load break device can be used on a conventional switch stick which is indicated by the elements 18, 20 and 21. This can be accomplished by providing an upstanding ear. 27 and an up standing plate 28 on the cap" 18. The elements 27 and 28 are for the purpose of receiving; the pivot pin 25 for the arm- 17. The plate 28 is given a large enough dimension so that it will serve as a barrier or wallbetween' the arm 17 of the load break device: and the handle 16 of the switch member so that the element 16 does notinterfere with proper functioning of the arm 17.

It will be appreciated that the switch stick 20 is still adapted to perform its conventional function even though the load break device is mounted thereon. The load break device which is mounted on the cap 18 may comprise a special fitting which can be fitted on the opposite end of a' conventional switch stick if so" desired.

The construction and mode of. operation of the second form of the invention illustrated in Figs. 6 and 7 is similar to that of the first form of the invention except that a single spring element 30. is substituted for the parts 17, 19 and 26 of the first form of. the invention. The spring 30 has an internal arm extension 30' which v serves the function of the arm 17, and an integral curved portion .30" which serves the function of the stop 26 of the arm 17.

The third form of the. invention which is illustrated in Figs. 8 and 9 provides a further simplification of the first and second forms of the invention and an additional advantage in that it better lends itself for use from either the right or left-hand side of theswitch member. The load break device consists of merely an arc interrupting or extinguishing cartridge 22 which is held by the holder 23 which in turn is mounted on a conventional switch stick 18, 20 and 21 by a spring" arm element 31. The spring element 31 has a curved end which extends in a direction which is generally transverse to the lengthwise axis of the stick 20. However, this curve portion of the arm 31 also extends in a direction which is generally parallel to the hook 21 as contrasted to transverse thereto as in the first and second forms of the invention; This makes it possible to use the combinedswitch stick and load break device at quite a distance from either side of the switch member as well as from in front of the cutout. Of course, the elements 31', 23 and 22 will ride successively along a side edge of the contact latch 3. When reclosing the circuit interrupter in order to avoid catching of the parts 22', 23 and 31,011 the underside of the latch 3 it will be necessary to tilt the switch stick slightly sideways. If the switch stick is tilted sideways when the switch is being opened then the arm. 31 doesnt have to be resilient but can be made rigid.

The fourth form of the invention illustrated in Figs. and 11 is a combination of the advantages of the second and third forms of the invention in that it provides a single spring element 32 similar to the spring 30 with integral stops 32', but its opposite ends are bent to provide a pair of arms 32" and 32" which carry a pair of cartridges 22. These arms 32" and 32" are bent into a closed loop to provide side guides around the contact latch 3. The arms 32" and 32 are fastened together by a clip 33 to close the loop and from this point the arms 32" and 32 are extended in opposite directions which extend transverse to the lengthwise axes of the stick 20 and hook 21. Accordingly, the outer ends of I the arms and the cartridge holders 23 and cartridges 22 will ride successively along the front edge of the contact latch 3. The sides of the arms which extend in a direction which is generally parallel with the lengthwise axis of the stick 2% provides side guides along the side edges of the contact latch 3 for the load break device. At its upper end the loop which is defined by the arms 32 and 32" is widened to accommodate the contact latch 3. The double cartridges are an advantage in that if one of the cartridges should prove to be defective and fail to interrupt the electrical arc the circuit interrupter can be immediately closed and the switch stick 20 reversed to interrupt the load with the remaining cartridge. This 6 is an advantage since the lineman may be highin the air on the line pole while he is usingthe switch stick mounted load break deviceand it is inconvenient for him to put in anew cartridge at this time. Of course, theswitch stick mounted load break device can be used while the lineman is on the ground or up on theline pole.

The fifth form of the invention differs from the preceding forms of the invention in that the cartridge is rigidly mounted on the switch stick.- A- rigid mounting can be used in the third form of the invention. However, when the arm 31 of the third form of the invention is rigid the operator must tilt the switch stick sideways during opening movement to insure that the parts- 31, 23, 22 and 24 will ride-successively along, the contact latch 3. In the fifth formof the invention a rigid mounting for the cartridge is used but without any necessity for sideways tilting of the switch stick. Thus, asshown in- Fig. 12, this is accomplished by connecting a resilient member suchas a leaf spring element 40 to the terminal 7 of contact latch 3. This requires no modification in the cutout since the terminal 7 is already provided. The cap 18 in this instance has a rigid arm 41 connected thereto which extends generally perpendicular to the switch stick 20 and the hook 21. Arm 41 can be connected to cap 18 by welding or other suitable means although it can be made integral with the cap 18 which typically is true of hook 21 At its outer end the arm 41 has cartridge holder 42 which is adapted to have cartridge 22 mounted therein.

When the hook 21 is engaged with eyelet handle 16 the cartridge 22 will have raised the spring. 40. This means that the spring 40 is continuously bearing down on the tip 24 as the fuseholder 2 is being opened so that the tip 24 is the last point of electrical contact between the upper end of the fuseholder 2 and the contact latch 3. Therefore, the are which is drawn therebetween will terminate on the tip 24. The are will burn through tip 24 whereby the compressed gas is released from cartridge 22 to cool and deionize theme. 7

In all forms of the invention the member or cartridge for interrupting the load current are has been illustrated as being small withrespect to the apparatus with which it is used and with respect to the switchstick on which it is mounted and carried, although this is not mandatory. However, a small one is preferred since then itwill be lightweight, low cost, easy to handle, and convenient to use with conventional switch sticks and in the limited free space at conventional switches and cutouts. Since they are low cost they can be expendable without incurring high costs. Also, since they' are small several of them can conveniently be carried by a lineman in a cartridge magazine hooked on his belt.

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. A switch stick mounted load break device comprising a switch opening stick, said stick having a hook member mounted on one end thereof for manually opening a switch with said stick, and a small expendable and replaceable electrical arc extinguishing member movably and resiliently mounted on the same end of said stick for extinguishing an electrical are which is drawn at a switch when it is opened with said stick, said expendable and replaceable member being mounted on said stick by an arm which is connected to said one end and extends beyond said one end and carries said electrical arc extinguishing member beyond said one end and said expendable and replaceable electrical arc extinguishing member being small with respect to said stick and switch.

2. In a load break device as in claim 1, wherein said 'arm extends first in a direction which is generally parallel to said stick and then generally transverse to said stick.

' 3. In a load break device as in claim 2, wherein said arm is pivotally connected to said one end and is biased by a spring.

4. In a load break device as in claim 2, wherein said arm is constructed from resilient material.

5. In a load break device as in claim 4, wherein the outermost generally transverse direction of said arm is also generally transverse to said hook member.

6. In a load break device as in claim 4, wherein the inner end of said arm is coiled.

7. In a load break device as in claim 4, wherein the outermost generally transverse direction of said arm is also generally parallel to said hook member.

8. In a load break device as in claim 6, wherein a continuation of the inner coiled end of said arm provides a second arm which at its outermost end extends in a transverse direction opposite to the first recited arm and carries a second electrical arc interrupting member.

9. A device for manually separating an open-type switch member from a contact and extinguishing an electrical arc which is established between said contact and switch member, said device comprising an electrically insulated switch stick having electrically conductive means on one end thereof which is adapted to be engaged with an electrically conductive portion of said switch member for manually separating said switch member from said contact, a small expendable and replaceable electrically conductive cartridge which is mounted on the same end of said switch stick as said means and is in electrically conductive relationship with said means, said cartridge being adapted to produce a pressure blast into said electrical arc in response to termination of said electrical arc thereon, and means for making said cartridge the last point of electrical contact between said switch member and said contact.

10. In a device as in claim 9, wherein said cartridge is mounted on said switch stick in an electrically conductive and movable cartridge holder which is electrically connected to said electrically conductive means, and said means for making said cartridge the last point of electrical contact between said switch member and said contact comprises spring means for moving said cartridge into contact with said contact as said switch member is being manually opened with said switch stick.

11. A device for manually separating an open-type switch member from a contact and extinguishing an electrical are which is established between said contact and switch member, said device comprising an electrically insulated switch stick having an electrically conductive hook member on one end thereof which is adapted to be engaged with an electrically conductive eyelet handle of said switch member, an electrically conductive curved arm which is mounted on said one end in electrically conductive relationship with said hook member, said arm extending away from said one end first in a direction which is generally parallel to the axis of said stick and then being curved in a direction which is generally transverse to said axis, an electrically conductive cartridge holder mounted on the outer end of said arm, said holder having an electrically conductive small expendable and replaceable cartridge therein which is adapted to generate an electrical arc extinguishing pressure blast into said electrical arc in response to termination of said are thereon, and spring means for making said cartridge the last point of electrical contact between said switch member and said contact by biasing said arm and then said holder and then said cartridge into contact with said contact as said switch member is being manually opened with said stick.

12. A switch stick mounted load break device comprising a switch stick having an expendable and replaceable electrical arc extinguishing member mounted thereon which is adapted to extinguish an electrical are which is established at an open-type switch member when said switch member is manually opened with said switch stick, said electrical arc extinguishing member comprising a cartridge which is adapted to produce a pressure blast into said electrical arc.

13. A switch stick mounted load break device comprising a switch stick having an expendable and replaceable electrical arc extinguishing member mounted thereon which is adapted to extinguish an electrical are which is established at an open-type switch member when said switch member is manually opened with said switch stick, said electrical arc extinguishing member comprising a cartridge which is adapted to produce a pressure blast into said electrical arc in response to termination of said electrical are on said cartridge.

References Cited in the file of this patent UNITED STATES PATENTS 700,809 Partridge May 27, 1902 2,438,746 Garrison Mar. 30, 1948 2,671,145 Lindell Mar. 2, 1954 2,750,471 McBride June 12, 1956 2,752,458 Baker et al. June 26, 1956 2,834,855 Carpenter et al. May 13, 1958 2,834,856 Charewicz et al. May 13, 1958

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