US2439264A - Electric switch - Google Patents

Description

AP 6 1948- w. E. PAUL ELECTRIC SWITCH Filed June 7, 1945 Inventor: william E, Pam,

His Attovn ey.

byl

lmfatented Apr'. 6, 1948 ELECTRIC SWITCH William E. Paul, Schenectady, General Electric Company,

New York N. Y., assigner to' a corporation of Application J une 7, 1945, Serial No. 598,041 9 Claims. (Cl. 20D-146) My invention relates to electric switches, and more particularly to those of the load break switch type wherein means are provided for interrupting load power currents as well as for carrying the normal load' current and disconnecting the circuit.

The problem of both interrupting and disconnecting a high voltage circuit at points where conventional power circuit breakers are impractical or uneconomlcal involves a number of diiiiculties including those associated with the usual requirements for simplicity and ruggedness in structure, compactness, economical construction and operation and electrical efciency, in both interrupting the load power arc and disconnecting the circuit. It would be 'desirable to have a load break switch which could be used anywhere, either indoors or outdoors, and which could also be used for taking power from transmission lines or distribution lines for farm power or other small installations along power lines. y

It is an object of my invention, therefore, to provide an improved load break switch that ls simple and inexpensive in construction, that is capable of eiliciently interrupting line charging currents and moderate load currents in high voltage power circuits and disconnecting the power circuits.

It is another object of my invention to provide a new and improved load break switch in which the interruption of the circuit is accomplished before any movement of the isolating portion of the load break switch occurs.

Still another object of my invention is the provision of a new and improved load break switch having a very high interrupting capacity with little or no maintenance required.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specication.

For a better understanding of my invention reference may be had to the accompanying drawing in which Fig. 1 is a, front elevational view with certain portions cut away, of an electric switch embodying my invention; Fig. 2 is a view taken on line 2--2 of Fig. 1, and Fig. 3 ls a sectional view taken on line 3-3 of Fig. 2.

Referring now to the drawing, the load break switch of my invention'comprises a pair of relatively xed terminals l and 2 which are suitably mounted on insulators or an insulating supporting panel, or the like. The terminal I, which forms the upper terminal ofthe switch ofmy invention has integrally formed therewith a contact' 3 comprising a plurality of contact lingers adapted to electrically engage with a cooperating contact 4 forming a part of the currentcarrying contact structure of my switch generally designated at 5. Preferably. the contact structure 5 comprises a pivotal supporting member G pivotally mounted at I to a stationary supporting member 8 supported on a suitable insulator 9.

The current-carrying contact structure 5, in addition to the pivotal support (i.A includes a tubular member or housing IU of insulating material which is mounted in sealed relationship to pivotal member 6, as by a clamping ring II. The other end of insulating tube lil is connected to an exhaust chamber i2 and is held in sealed relationship therewith by means of a clamping ring i3. Contact 4, adapted to cooperate with the contact 3, is mechanically supported from exhaust chamber I2. From the above, it will be understood that the current-carrying contact structure 5, hinged about pin 'l of the stationary support 8, constitutes a generally cylindrical disconnecting blade of the load break. switch of my invention.

Tubular insulating member, or housing, Ill forms a cylinder within which is disposed for reciprocal movement therein a movable support shown in the form of a long piston generally indicated at i4. Mounted within piston lll are a pair of relatively movable arcing contacts i5 and lli, contact it being indicated as a stationary contact with respect to piston irl and electrically connected by a flexible lead Il with Contact 4 to permit free piston movement in cylinder I0. Contact I5 is indicated as a hinge type contact pivotally mounted at I8 to the lower part of piston I4 and electrically connected by flexible lead I9 with pivotal supporting member 6, which in turn is electrically connected by means of a conductorA 20 to xed terminal 2. Movable contact l5 is mounted in a slot-like fluid blast passageway 2| provided within piston I4 and, in the closed position of contact l`5 as indicated in Fig. 2, this uid blast passageway 2l is closed, gatelike, by contact I5 bearing against contact I6.

Immediately above contacts I5 and i6 the oil blast passageway divides into two branches so as to define an arc dividing member 22. A suitable spring 23 supported in a recess 24 in contact I5 and engaging an abutment within Vpiston I4 biases contact l5 to the closed position. As will be ex- `plained in more detail later, piston I4 and the contacts l5 and I6 contained therein are caused to move downward within ,cylinder I at the commencement of the switch opening operation, whereby gate contact I is caused automatically to' pivot counterclockwise about pivot I8. In order that contact I5 may not be'unduly retarded during this opening movement, a venting passage 25 is provided in the upper portion of piston I4 for relieving the fluid from behind contact I5 in fluid passage I6.

Tubular housing III is adapted to be filled with a suitable arc extinguishing iluid 26 to the level indicated in Fig. 2. In the illustrated embodiment this fluid is shown as a liquid such as oil, for example. A suitable packing ring 21 is provided which constitutes the lower face of piston I4 so that upon downward movement thereof the fluid is displaced eilectively through blast passageway 2i thereby causing relative separation of contacts I5 and IB'to draw an arc therebetween. The blast of iiuid extends the arc against arc dividing member 22 and interposes a stream of fresh dielectricfbetween the separated contacts Vat 45 to a latch to cause rapid extinguishment of the arc and inv terrupt the circuit.

Movable piston I4 must be connected to external means for operating the same within cylinder l0 and to this end I have provided a pair of piston rods 28, preferably formed of insulating material for a substantial portion thereof and having a lower metal portion 29 adapted to be threadedly mounted as indicated at 30 to piston I4 as best shown in Fig. 3. As already noted, downward movement of piston I4 will cause the fluid in housing III to be displaced and moved relatively upward through piston I4 via passageway 2I. Upon return of piston I4 to its initial position it is desirable that this uid may rapidly return to the lower part of housing Io. Vent pasageway is insuillcient for this purpose and to this end, as shown by Fig. 3, I provide through piston I4 a plurality of passageways 3l, the upper ends of which register with a bore 32 in the lower metal ends 29 of piston rods 28` which bores 32 communicate to the fluid space in the upper end of tubular housing .Ill through openings 33 in the metal portions 29 of rods 28. In order that the main uid blast is prevented from going through passageways 3I upon downward movement of piston I4, a suitable check valve, such as a ball 34, is provided at the lower end of each passageway 3i.

The exhaust gases from a circuit interrupting operation are driven upwardly into exhaust chamber I2 which includes a gas cooling portion specifically indicated as a chamber 35 filled with gravel, or other suitable gas cooling material, generally indicated at 36. A suitable packing material 31 is provided where .operating rods 28 pass through exhaust chamber I2 to prevent oil or exhaust gases from escaping to atmosphere in that manner. Cooling chamber 35 is connected to exhaust chamber I2 through suitable ports 38 and to atmosphere through suitable ports 39. Any oil which might be blasted into chamber 35 is collected on cooling material 36 and is returned to housing I0 through ports 3B.

One of the objects of my invention, as was mentioned earlier, is to interrupt the circuit in the arc extinguishing structure comprising piston I4 or the like reciprccable within housing I0 before any pivotal movement of the hinged current-carrying contact structure 5 occurs,.or more specically, before any separation between contacts 3 and 4 occurs. Accordingly I provide an operating mechanism which causes piston I4,

during aninterrupting operation, to be moved downwardly in housing I0 from the position shown in Fig. 2 to interrupt the current ilowing between terminals I and 2 before any separation between contacts 3 and 4, or even relative movement of contacts 3 and 4 occurs. Pivotal supporting member 8,.which is a U-shaped member as indicated in Fig. l, is provided with a curved or arcuate slot 40 in each arm of the U. A pair of side operating rods 4I connected at their upper ends to piston rods 23 by means of a common cross-head pin 42, are each provided with a pin 43 at the lower end thereof adapted to move in 'arcuate slots 4i). Pins 43 are also connected to a pair of levers 44 pivotally mounted as indicated 4S, which latch 46 is in turn pivoted as indicated at 4l to pivotal support 6. The other end of lever 44 is preferably connected as by an operating rod 48 to suitable means for operating the switch to the open and closed posi- ,y

tions. Such means might comprise spring opening means with either manual or solenoid means for closing the switch and charging the spring opening means. In the closed position of the switch shown in Fig. 2 latching member 456 is adapted to engage a spring biased plunger 49 mounted in an extension 5d of stationary supporting member d. Upward opening' force ap- `plied to levers lll by the operating rod it will be approximately equal to the downward force exerted on rods II at pins 53 since the portions of levers ifi on either side of pivot i5 are not greatly dinerent in length. .The moment tending to rotate the blade clockwise about pivot I is made up of a. downward force exerted on rods 4I at pins i3 and the distance between pivot 'I and the line of action of the downward force at pins 33. Since this distance is relatively short, the clockwise moment is relatively small. The moment tending to rotate the blade counterclockwise is made up of an upward force, substantially equal to the above downward force, which is exerted by rod i8 and the distance between pin 'I and the line of action of the force applied on levers fili by rod (i3. Since this latter distance is relatively large, the counter-clockwise moment applied to the blade would greatly overbalance the above clockwise moment, and the -net ei-ect is a moment tending to rotate structure 5 in the counter-clockwise direction. The same result will be reached if the counterclockwise moment be regarded as made up of a relatively large upward force applied to pin fil and the distance between pivot l and the line of action of such upward force. When an upward opening force is applied to the operating rod 48 a strong downward thrust is exerted on piston I4 by .piston rods 28 through the tensioned operating rodsdI and the lever i4 pivoted at 45,

but because of the resistance to movement of the piston I4 by the fluid below it in the cylinder III a strong overturning moment is applied about the pivot I to the whole current-carrying contact structure 5 (hereinafter to be termed the blade for convenience) tending/to rotate itAcounterclockwise so as to separate contacts 3 and 4. However, the latch 46, held by plunger catch 49, prevents such disconnecting swing of the blade so that at this time lever 44 can only pivot about 45 with pins 43 moving downwardly in slots 40 accompanied by the corresponding downward movement of piston I4 by which interruption of the circuit is achieved by sepaarcuate slots 40 of supporting member 3 in eccentric relationship with respect to pivot 45 so that, in the closed position as shown, the lower ends of slots 40 are closer to pivot 45 than their upper ends; consequently, as lever 44 rotates, its floating fulcrum 45 is forced to the right in planetary relationship to pivot 4l by the cam action ol the eocentrically arranged slots 40 upon the pins 43. Because the planetary movement of pin 45 about pivot 4l is effected by the latch 45 yit will be obvious that this clockwise rotation of the latch will result in its eventual disengagement from the restraining plunger catch 49. Coincident with the freeing of latch 46, the abovementioned overturning movement about fixed pivot I will now be effective to swing the blade outwardly for disconnecting the isolating contacts 3 and 4. In the embodiment shown, this disconnecting swing of the blade is further augmented by the thrust of spring means 58- biased against a cooperating fixed surface 59, although this spring arrangement performs another function as will be'explained later. I proportion the eccentricity of the slots 40 and the dwell of the coacting latching surfaces so that the latch 46 is released when the piston I4 has moved approximately two thirds of its downward stroke (that is, with .the lever 44 rotated so that the pins 43 have moved correspondingly two thirds o1' their permissible travel in the slots 40; for it will be clear that the length of slots 4I! determines the stroke of piston I4) and by winch time the circuit will `have been interrupted between the separated contacts I5 and I6. In view of the above explanation, it will be understood that, upon disengagement of the latch 4S, the upward movement of the operating rod 48 now produces simultaneously (a) a local pivotal movement of lever 44 about its goating fulcrum 45 and (b) a pivotal movement of the entire blade about its fixed pivot 'I'. Accordingly, while the local pivotal movement of lever 44 is producing a follow-through blast in piston I4 which is eiective to maintain contact I5 open after interruption, the pivotal movement of the entire bladel is causing a progressively widening isolating gap between disconnecting contacts 3 and 4. If it so happens that the pins 43 reach the bottom of the slots 40 toward the end of the opening movement of the blade, it'will be discerned that the lever 44 becomes a positive drive member between the upwardly moving operating rod 48 and the pivotal supporting member 6 without the interventi-on of the fluid drive element constituted by the fluid below piston I4 in cylinder I Il.

For establishing an open position for the blade with a safe isolating gap between contacts 3 and 4, I provide an extension on the pivotal member 6 and on the ilxed supporting member 8, one of which has a dashpot piston as at 5I and the other a shallow cooperating cylinder 52 thereby to cushion the blade as it assumes its full open position. y

With the arrangement described thus far, spring 23 will close contacts I5 and I6 upon com- Ipletion of the opening operation so that, upon reverse or downward movement of operating rod 48 to its original closed position as shown in the drawing, the circuit necessarily would be reestablished by the reengagement of contacts 3 and 4. It might be desirable in many cases to complete the circuit under the fluid or oil, such as at contacts I5 and I5, rather than at contacts 3 and 4. Accordingly, suitable hold-open means may be provided to hold contact I5 in the open position once it has opened until contacts 3 and 4 have reengaged. For this purpose I provide a magnetic member 53 on the back of the free end of contact I5. I also provide a magnet 54 mounted in suitable supporting means 55 outside of tubular housing I0 so that when contact I5 is opened it can be magnetically held in the open position by magnet 54 while the switch blade is open. The magnet 54 and its supporting means 55 is preferably mounted for lateral movement in a suitable supporting guide means 56 which in turn is fastened to operating rods 4I as by means of clamping screws 5l so that magnet 54 will be properly aligned with respect to magnetic member 53 at all times even when piston I4 and contact I5 reciprocate within and move relative to housing I0. Supporting means 55 for magnet 54 is preferably biased by spring means 58 so that magnet 54 is urged thereby to a position of abutment against the exterior wall of housing il! and in which position it is capable of holding the contact I5 open alter it has been opened and maintained open temporarily by the fluid blast as already described. This hold-open position of the magnet supporting means 55 is only possible while the blade at least is partially open, for I provide a fixed stop surface as indicated at 59, in stationary relationship to the supporting structure or panel upon which the switch is mounted, positioned for intercepting the slidable means 55 as the blade" approaches closed position. Therefore, when the blade has fully closed, magnet means 55 will have assumed a position toward the left with respect to cylinder I0, as is clearly shown in Fig. 2, in which position the increased gap produced between magnetic members 53 and 54 renders magnet 54 incapable of holding the contact I5 open. Accordingly, not until the blade closes, with disconnecting contacts 3 and 4 in substantial engagement, will contact I5 be released from open position to close against contact I6 under the bias of its spring 23 for rea-establishing the circuit between terminals I and 2. Hence, it will be understood that when the magnetic arrangement of my invention is employed for holding and releasing contact I54 in the above-described manner, both the interruption and reconnection of the switch circuit are effected by the relatively movable contacts I5 and I5 operating in the fluid contained in cylinder Ill; so that the contacts 3 and 4 function solely as disconnecting or isolating contacts which are not subjected to arcing conditions.

In view of the 'detailed description included above the operation of the load break switch embodying my invention will be obvious to those skilled in the art. With the switch in the position as indicated in the drawing, opening thereof is obtained by upward movement of operating rod 48. This causes a counter-clockwise rotation of lever 44 and a downward movement of pins 43 in arcuate slots 4I). This furthermore causes operating rods 4I and piston rods 28 to move piston I4 downwardly in housing I0. Such downward movement of piston I4 compresses the uid beneath piston or movable support I4 forcing it at high velocity between contacts I5 andl I6, with the consequent high speed interruption of the arc drawn therebetween by fluid blast action cooperating with arc dividing member 22. As long as the hinged current-carrying contact structure 5 or blade is closed with respect to contacts 3 and 4, magnet 54 is too far away from magnet member l53 to hold contact l5 in the open position. However, the uid blast through passageway 2'I maintains contact I5 in the open position. Continued movement of pins 4.3in arcuate slots 40 causes latch 48 to rotate free from latching plunger 49. When pins 43 have moved approximately two thirds of the way down arcuate slots 40 latch 48 is released. Pins 43 continue to move downwardly with continued movement of -piston I4 and a continued fluid blast between contacts I5 and I8 while, coincidently, the blade begins to swing to theieft about pivot 1, as viewed in Fig. 2, to provide an isolating gap between contacts 3 and 4. As soon as magnet supporting member 55 is free of xed member 59 magnet 54 lies abuttingly against cylinder I and magnetically holds contact I5 in the open position. The blade" is cushioned by cushioning means comprising members I and 52 and brought to rest in its full open position. l

To reclose the switch a downward force is applied to operating rod 48 which immediately moves pins 43 from the bottom to the top of arcuate slots 40 thus resetting piston I4 for another interrupting operation. The uid above piston I4 can now return freely past valves im through passages 3i to its initial position. 'When pins443 reach the upper end of arcuate slot il@ a continued downward force on operating rod d8 applies a positive drive to the blade to rotate it about pivot 1 to its closed position in Fig. 2 to reclose contacts 3 and 4. As the blade reaches its closed position latch 45 z noves spring biased plunger 49 to the right until it is beneath plunger 49 whereupon the operating mechanism is in condition `for a subsequent closing operation. When magnet supporting member 55 engages stationary member 59 the gap between magnet 5e and magnet member 53 increases sufiiciently so that magnet 54 is no longer capable .of holding contact I5 in the open position. Thereupon the circuit is nally completed between contacts i5 and I6.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departingfrom my invention in its broader aspects and I, therefore, aim in the appended claims to cover all such changes and modications as fall within the true spirit and scope of my invention.

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

1. AAn electric switch comprising a pair of relaing a piston having an axial opening therein and` a .pair of relatively movable contacts mounted within and supported by said piston so as to close said opening in said piston when said switch is closed, means for causing movement of said piston.' an arc extinguishing liquid-arranged so as to be forced through the axial opening in said piston and between said contacts to cause relative separation thereof and interrupt the current nowing therethrough in response to movement o said piston, and means for moving said current-carrying contact structure from between said terminals while said contacts are in the open position and said liquid is owing therebetween.

3. An electric switch comprising a pair of relatively fixed terminals, a current-carrying contact structure arranged electrically to bridge said terminals comprising a tubular member of insulating material, a body of arc extinguishing fluid in said 'tubular member, a piston of insulating material reciprocal in said tubular member and having -an vopening therethrough arranged so that said iiuid is forced through said opening in response to movement of said piston, a pair or relatively movable contacts for completing the circuit through said contact structure mounted within and supported by said piston arranged when closed for blocking said opening through said piston, means for causing movement of said piston so as to force said iiuid through said opening to separate said contacts and blast the arc drawn therebetween are in the open position and said nuid blast continues between said contacts.

4. An electric switch comprising a pair of relatively fixed terminals, a pivotally mounted current-carrying contact structure arranged electrically to bridge said terminals, an arc extinguishin'g unit disposed in said contact structure comtively iixed terminals, a current-carrying contact structure arrangedelectrically to bridge' said terminals, an arc ei'xtinguishing unit disposed in 2. An electric switch comprising a pairot relaf tively xed terminals, a current-carrying .contact structure arranged electrically to bridge said movement of said piston,

terminals, an. arc extinguishing unit disposed in said current-carrying contact structurecomprisprising a pair of relatively movable contacts and a movable support carrying said contacts, means for causing movement of said support, a iluid ar- ;ranged so as to be forced between said contacts to open the same and interrupt the arc drawn therebetween in response to movement of said support, and means for pivoting said currentcarrying contact structure out of bridging relationship across said terminals while said contacts are in the open position and said uid is flowing therebetween.

5. An electric switch comprising a pair of relatively iixed terminals, a current-carrying contact structure arranged electrically to bridge said terminals, an arc extinguishing unit disposed in said current-carrying contact structure comprising a piston and a pair of relatively movable contacta mounted within-and supported by said piston, meansfor causing movement of said piston, a iiruid arranged so as to be forced between said contacts to cause relative separation thereof and interrupt the current iiowing therethrough in response to movement of said piston, operating means for moving said current-carrying contact structure to cause disconnection and subsequent reconnection of said structure with respect to said terminals, means interconnecting vsaid operating means and said piston moving Vmeans to cause separation of said contacts prior to said disconnectiomand means for holding said contacts separated after saiddisconnection until said reconnection has been enacted. I

6. An electric switch comprising a pair of relatively xed terminals, lva pivotally mounted current-carrying contact structure arranged electrically to bridge said terminals, a tubular housing for said contact structure, an arc extinguishing unit disposed in said housing comprising a pair of relatively movable contacts and a support carrying said contacts movable in said housing, means for causing movement of said support, a fluid in said housing arranged so as to be forced between said contacts to open the same and interrupt the arc drawn therebetween in response to movement of said support, and means for pivoting said current-carrying contact structure out of bridging relationship across said terminals while said contacts are in the open position and said iluld is iiowing therebetween,

7. An electric switch comprising a pair of relatively ixed terminals, a pivotally mounted current-carrying contact structure arranged electrically to bridge said terminals, an arc extinguishing unit disposed in said contact structure comprising a pair of relatively movable contacts and a movable support carrying said contacts, means for causing movement of said support, a iiuid arranged so as to be forced between said contacts to open the same and interrupt the arc drawn therebetween in response to movement of said support, operating means for pivoting said current-carrying contact structure to cause disconnection and subsequent reconnection of said structure with respect to said terminals, means interconnecting said operating means and said support moving means to cause separation o! said contacts prior to said disconnection, holding means for maintaining said contacts separated until said reconnection has been effected, said holding means comprising a magnetic member shiftable between releasing position and holding position in accordance with the disconnecting and reconnecting movements respectively ci said structure.

8. An electric switch comprising a pair of terminals, an interrupting unit including a pair oi separable arcing contacts provided with means for biasing them into closed position, said unit being arranged in series relationship with respect to said terminals, switching means for isolating said interrupting` unit from one of said terminals, means for providing a. blast of iluid Number 10 for said nnit whereby to separate and4 blast said contacts to extinguish the arc drawn therebetween, means for operating said switching means 'to disconnecting position following said separation of said contacts and for thereafter reconnecting said switching means, and holding means for maintaining said contacts separated while said switching means remains disconnected from one of said terminals, said holding means comprising a magnetic member shiftable between releasing position and holding position in accordance with the disconnecting and reconnecting movements respectively of said switching means.

9. An electric switch comprising a pair of terminals, an interrupting unit including an elongated chamber and a structure disposed for reciprocal movement therein, said structure having an opening therethrough and a pair of relatively movable contacts for completing a circuit through said unit mounted within and supported by said structure arranged when closed for blocking said opening through said structure, a fluid in said chamber, said interrupting unit being arranged in series relationship with respect to said terminals, switching means for isolating said interrupting unit from one of said terminals, means for actuating said switching means to isolating position, and means for causing movement of said structure so as to force said fluid through said opening whereby to separate said contacts and blast the arc drawn therebetween prior to the isolating movement of said switching means.

WILLIAM E. PAUL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Balachowsky May 16, 1939 Prince May 30, 1939 Ludwig et al. Feb. 10, 1942 Parker Nov. 10, 1942 v Certificate of Correction Patent No. 2,439,264. April 6, 1948.

WILLIAM E. PAUL It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction es follows: Column 8, line 3l, claim 3, after therebetween insert and means for moving said current-carrying Contact structure from between said terminals 'while said contacts; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of August, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommzssioner of Patents.

Certificate of Correction Patent No. 2,439,264. April 6, 1948.

WILLIAM E. PAUL It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 8, line 31, claim 3, after therebetween insert and means fm1 mom'ng said current-carrying contact structure from between said terminals 'while said contacts; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of August, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

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