US1873797A - Electric switch - Google Patents

Description

Au 23, 1932. R T RNER 1,873,797

ELECTRIC SWITCH Filed Jan. 10, 1931 2 Sheets-Sheet l Illh lg mu lg ,1 V f l8 /0 Z8 4 I/ 25 I 27 4 .1' ,2 /6 6 a 3 I 00 L I I o :i c 3 I h I IIH IIIIHL 5 Inventor: .52 8

7& Harold R Turner, 2 5 U7 y MW HL-s Attorney.

Aug. 23, 1932. R E 1,873,797

ELECTRIC SWITCH Filed Jan. 10, 1951 2 Sheets-Sheet 2 Inventor Harold R .Turnen y WWW Hts Attorney.

Patented Aug. 1932 UNITED STATES PATENT OFFICE HAROLD B. TUBHEB, OF PITTSFIELD, MASSACHUSETTS, ASSIGNGR TO GENERAL ELEC TRIO COMPANY, A CORPORATION OF NEW YORK amcrmo swr'rcn Application filed January 10, 1931. Serial No. 507,882.

My invention relates to improvements in electric switches and more particularly to multiple-throw disconnecting switches for use where space is limited and safety for both personnel and apparatus is paramount.

In low voltage alternating current distribution systems the transformerstations at the ends of the feeders, usually cables, are located in vaults, the size of which is restricted by economic factors and underground congestion. Inasmuch as the feeder circuits are. operated at relatively high voltages, ranging from 4,000 to 33,000 volts, the necessary insulation in view-of the space limitations is of great importance especially for switches. Be-

cause of these limitations it is desirable to minimize failure of the insulation by using inorganic insulating materials such as ceramic material. For economy and safety, however, such materials must be so utilized as to obtain the maximum advantages from their static roperties. To this end it is desirable to ma e use of their high resistance to compression. Moreover, contact heating, corrosion and burning should be minimized and the use of flexible conductors avoided since these, by reason of their lack of rigidity, are apt to get out of their intended places and cause short-circuits. Above all, it should not be humanly possible for a person to cause in jury to himself or others in testing, operation and maintenance of the switch. In this connection, it is frequently desirable that a switch left unlocked in the open-circuit position should not remain in such position.

An object of my invention is then to provide an improved and simple switch which is compact. Another object of my invention is to eliminate flexible conductors Within the switch and to provide a construction such that inorganic insulating materials can be used to the best advantage. A further object of my invention is to provide a switch which if left unlocked in the open-circuit position will automatically assume a safe circuit closing position. Other objects of my invention will appear hereinafter.

My invention will be better understood when considered in connection with the ac-.

companying drawings and its scope will be pointed out in the appended claims. I,

In the accompanying drawings, Fig. 1 illustrates a side elevation of a switch embodying my invention; Fig. 2 is an end elevation of the switch shown in Fig. 1; Fig. 3 is aside elevation partially in section of an operating handle mechanism for switches embodying my invention. Figs. 4, 5, and 6 are end elevations of the-operating mechanism of Fig. 3, Fig. 4 illustrating one circuit closing position, Fig. 5 illustrating a circuit open position and Fig. '6 a position intermediate those shown in Figs. 4 and 5. Fig. 7 is an exploded perspective view of the mechanism of Fig. 3. 6 Fig. 8 is a circuit diagram illustrating oneapplication of the switch shown in 'Figs.1 and 2. Fig. 9 is a circuit diagram of another application of a switch embodying my inv vention. v

The embodiment of my invention chosen for the purpose of illustration is a three-pole, double-throw disconnecting switch including a plurality of spaced pairs of contacts 10, 11 and 12, 13, a conducting member such as a straight flat strip conductor 14 extending from one contact 10 of one pair to one contact 12 of another pair and means for engaging or bridging one pair of contacts at a. time such as a cooperating movable contact 15 which has a portion ad acent the conductor 14 and is arranged for movement into contacting position between this conductor and each of the contacts connected thereby. As shown, the pairs of contacts are oppositely' disposed and the conductor 14 connects corresponding contacts 10 and 12 of the two pairs. In addition to performing the function of a guide for the movable contact 15, the conductor 14 may also act as a connector between the contacts 10 and 12. For the guiding function, the portion of the bridg ing contact 14 adjacent the conductor 14 may be shaped to provide bifurcations 16 which straddle the conductor 14. In order to'insure a good contact with a high pressure or wedging action, the contacts 10, 11 12 and 13 may be of the jaw ty e illustrated and the end portions of the bri ging contact wedge shaped in the manner illustrated in transformer.

Fig. 1. The end portions 16 of the bridging contact are suificientl spaced so as to ride freely along the con uctor 14 so that high pressure contact action between the contact jaws and the contact portions 16 occurs only as the wedging condition is effected near the end of the contact movement. If desired the bifurcations or end portions 16 may have a slight flexibility just sufiicient to enable contacting action involving engagement of the end portions 16 with both the jaws of the contacts 10 or 12 and the conductor 14.

Where the switch is to be used in vaults with the contacts immersed in oil, a fluidtight metallic casing 17 may be employed for the purposes of kee ing the oil in and moisture and other flui 5 out. Within this casing the stationary contacts 10, 11 and 12 are mounted on suitable insulators 18 which are illustrated as of the porcelain type. These insulators are secured to a suita le supporting structure such as a frame 19, which may be mounted on angle brackets 20 within the casing, as shown. Where the switch, when.

in one of its circuit closing positions, is to act as a grounding switch, one of the contacts, for example 13, may be mounted directly on the casing, as shown in Fig. 2, and the casing suitably grounded. Otherwise the contact 13 may be insulated as are contacts 10, 11 12. The contacts 11 and 12 are connected to terminals 21 and 22 respectivel the latter extending through the casin wa l in bushings which may, if desired, be inserted in the housing of a transformer so that the switch can be secured directly to the For actuating the bridging contacts 15 they are mounted between insulators 23 and 24 which are suitably secured to a cross rod 25. This rod is provided with means arranged to insure a rectilinear movement of the contacts 15. As shown, this means includes two spaced pins 26, 27 which travel in slotted guide-ways 28. Inasmuch as the switch may have to pass greater currents in the loweror grounding position that is contact 15 bridging contacts 12 and 13, than in the upper position, bridging contacts 10 and 11, I so construct and arrange the lower contacting portion of the contacts 15 as to rovide a greater current carrying capacity t an the upper contacting portions and correspondmgly increase the contact capacity of the contacts 12 and 13.

For actuating the movable contacts 15 to the different circuit controlling positions, I provide an operating mechanism which is arran ed to maintain the switch in one circuit c osing position but which under the bias of the weight of the movable contacts 15 and their supporting structure, tends to move the contacts 15 to another circuit closing position if the switch is not in the first circuit closing position. As shown, this mechanism includes an operatin shaft 29 one or more cranks 30 secured t ereto and pins 27. In the upper circuit closin position of the contacts 15 where they bridge the contacts 10 and 11, each crank 30 and its associated link 31 form an overset to gle for holding the switch closed, the trave of the operating shaft 29 in the direction of overset being limited as will hereinafter appear.

For actuating the shaft 29, I provide a handle operating mechanism, which is shown in Fi 3 to 7 inclusive, whereby to permit a pre etermined or limited movement of the contacts 15 from the upper circuit closin position in engagement with contacts 10 an 11 to an intermediate circuit opening posi-' tion as shown in Fig. 2 and a greater movement of the contacts 15 only on return to the upper circuit closing position and release of an interlockin device after which the contacts 15 may he moved to the lower circuit closing position in engagement with contacts 12 and 13. As shown, the handle mech-' anism include a supportin member such as a base 32 which is secure to the casing 17 by suitable means such as bolts 33, suitable packing 34 being interposed as shown in Fig. 3. Mounted in the base 32 so as to project therethrou h within the casing to en age the shaft 29 cl utch fashion for examp e, is an operating member or handle 35, the shaft portion of which asses through suitable packing and a land bushing 36 to provide a fluid-tight sea A retaining screw 8 may be used to hold the handle member 35 in en agement with the shaft 29. p

or looking the operating member 35 in any one of its ositions,I rovide cooperatin locking mem rs 37 an 38 both of whic are mounted on the operatin member 35. The locking member 37 is ri with respect to the operating member 35%iut the locking member 38 is arranged for movement relativel thereto and carries a lockin pin 39 which is arran ed to be engaged in oles 40, 41 and 42 in the base 32, whereby to maintain the switch in its difierent circuit controlling positions. The locking member 38 is provided with an additional guiding pin 43 such that it cannot be turned angularly about its pin 39 and is so arranged that it cannotbe withdrawn or separated from the operating handle 35. Each of the locki members 37, 38 may be provided with an opening or eye-for the insertion of a padlock 9 so that the switch can-be purposely locked and kept under the supervision of authorized members of the personnel in any one of the circuit controlling positions. The base is provided with motion limiting lugs 44 and 45, the former determining the overset of the toggle formed by the crank 30 and the link 31. Obviously the limiting lugs could be ad-- 'links 31 connectingthe cranks to the ower lso justable and placed elsewhere, for example to be en aged by cranks 30.

In or er to prevent thoughtless operation of the switch assuming that the locking members are not padlocked I provide the handle operating mechanism with amotion limiting means which as shown'includes a pin and slot mechanism. The pin 46, seeFigs. 3 and 7 is carried by the operating member 35 on the lower side thereof and is movable from the upper side by the crank 47. This pin 46 engages a slotformed between projections orwalls 48-on the base 32 and having one "5 end closed as shown. When the operating 29 on the base 32'and the operating'handle may be moved to the position shown in Fig. 5

which is the intermediate or open circuit (poj sition of the switch shown in Figs. 1 an If it is desired to move the switch to the lower position where the contacts 15bridge the contacts 12 and 13, then the operating handle 35 must be returned to the closed position where the crank 47 may be turned to release the pin 46 from the slot on the base 32 and the handle 35 then turned counter-clockwise as shown in Fig. 6. It is there fore impossible. for the operator to throw the switch from the upper circuit closing position or from the intermediate or open position to the lower or grounding position without some thought on his partwhereby he may be reminded of the possibilitypf completing the ground connection on a line circuit, it being assumed that the circuit 49 (see Fig. 8) comes in through the terminals 22.

In the schematic circuit arrangement shown in Fig. 8 to illustrate an application of a switch embodying my invention, a polyphase high voltage circuit or feeder 49 is adapted tobe connected to a low voltage neti work 50 through the contacts 10 and 11 of means 53 may a switch such as shown in Figs. 1 and 2, a step-down transformer 51 and a circuit .breaker 52. Electromagnetic finterlocking be connected across a phase of the network as shown so that whenever the circuit breaker 52 is closed and the net: work is energized, or the feeder 49 is energized, the electromagnet will be excited to lock the operating mechanism throu h notches, for example, in one of the cran s 30 so as to prevent operation of the switch on a live circuit. This insures the operators safety since it is thus im ossible to open the disconnecting switch un er load.

Assuming that the feeder disconnecting switchis in the circuit closing position, that is, that the contacts 10 and 11 are bridged 55 by the contacts 15 and that the circuit breaker operating 52 is closed and either the feeder 49 or the network 50 or both are energized, it will be impossible to operate the switch since the electromagnetic means 53 is energized and engages a notch in one of the cranks 30. Under these conditions, the disconnecting switch operating handle mechanism has its parts positioned as shown in Figs. 3 and 4. If for-any reason it is desired any of the equipment in the vault or chamber containing the transformer 51, the circuit breaker 52 and the disconnecting switch, the operator must first arrange to ave the feeder circuit 49 o ened, for example; at the power station an must effect the opening of the circuit breaker 52. The electromag netic means 53 "is thus deenergized and t locking of the switch mechanism thereby released. Whoever is authorized may unlock the padlock 9 thus unlocking the handle operto work on nism were not locked prior to the o ning of the circuit breaker 52 and the f er cir- 'cuit 49, it would still bev impossible to move the operating handle-since the electromagnetic interlocking means 53 would be engaged. Assuming, however, that the interlocking means disengaging the locking pin 39 from the base 32, the operating handle 35 can be turned counter-clockwlse into the circuit open position shown in Fig. 5 and the switch parts are then positioned as shown 'in Fi 1 and 2. The operating handle 35 may I locked in this position, if desired, by setting the locking pin 39 in the hole 41 on the base 32 and inserting the padlock in the eyes of the locking members 37, 38 if it is desired to lock the switch against unauthorized operation.

In order further to insure safety so that the switch cannot be left in the open circuit position with the possibility of some one then moving it to the grounding plpsition on b: Ii;

00 mg mem r circuit, I so arrange the that its locking pin 39 cannot enter the hole 41 unless the safety locking pin 46 is in its coslot. In other words, if the pin 46 is not in its slot, the switch will go to the grounding position immediatelgeupon release of the o eratin'g handle 35 a r movement thereof rom the upper circuit closing position. For this purpose the guiding pm 43 is so arranged as to be in the path of movement of the crank 54 which carries the safety pin 46 and is of such a length that, with the in 46 out of its slot, the member 38 is ra' so muchthat the locking pin base 32 and therefore cannot be inse in the hole 41. Thus in moving from the upper circuit closing position it is necessaryto raise the lockingl member 38 so that the pin 39 clears the crank 54 moves under the pin 43 the pm 39 is clearof the ole 40. Then if the crank 47 is operated to move the pin 46 from the slot, the

shown in Figs. 1, 2 and 5 39 cannot enter the hole 41. Consequently, if the operating toggle 30, 31 is released and the handle 35 not held by the operator, the switch will under the bias of gravity go to the grounding position. Therefore the switch cannot be left in the open position and then operated to the grounding position without first going to the closing position where if the circuit 49 is energized, the switch will be locked by the electromagnetic means 53.

If the switch is moved to the open position and left in this position with the locking pin 39 in engagement with the hole 41 of the base 32, it may be that an operator or maintenance man might come along and release the member 38 and try to move the operating handle to the ground position. This of course cannot be done if the electroma netic interlocking means 53 is energized. I? however the switch is in the open position and the circuit breaker 52 is opened and in the meantime the feeder 49 has been energized, for example by closing a switch at the power station, then the inter locking means 53 would be deenergized. Now, if the operating member 35 could be moved to the ground position, a polyphase short-cir cuit would be put on the live feeder 49. This of course must not be done. If under these conditions the operator attempts to move the contacts 15 to the ground position bridging contacts 12 and 13, he will find it impossible to do so since the pin 46-eomes to the closed end of the slot on the base 32 when the operating member 35 is in the switch open position. Consequently, the operating handle must be moved from the open position back to the closed position shown in Figs. 3 and 4 before the pin 46 can be released from the slot. However, when the operator completes this closing movement if the feeder 49 is energized, the electromagnetic interlock 53 will be energized even though the circuit breaker 52 is open. Consequently, as soon as the switch is returned to the closed position, it will be locked there by the electromagnetic interlock 53 and the operator will be unable to move it from this position. If however the feeder 49 were not energized and the circuit breaker 52 were open when this return movement to the closing position is made, the operating handle 35 would be free for movement to the ground position upon turning the crank 47 so that the pin 46 associated therewith is moved out of the slot in the base 32. The operating handle may then be moved to the grounding position with the contacts 12 and 13 bridged by the contacts 15. In this position the locking pin 39 may be engaged with the hole 42 1n the base 32 and a padlock inserted through the eyes in the looking members 37 and 38 if it is desired to prevent unauthorized operation.

If at any time while the switch is in the grounding position the feeder 49 should be the pin 46 will automatically fa 1 contacts 15 that the feeder could not be maintained energized without giving notice at the power station that something is wrong.

When the operating handle is returned to the closed position shown in Fi 3 and 4,

into position in the slot of the base 32 due to the effect of gravity when the operating mechanism is mounted, as shown in Fig. 1, but obviously any other suitable biasing arrangement may be employed. It will be noted that if the switch is moved to the open-circuit position and is not held there by the in 46 having come to the end of the travel in the slot the will, under the bias of gravity, drop into the grounding position, assuming of course that the electromagnetic interlocking means 53 is not excited.

In the schematic circuit arrangement shown in Fig. 9, to illustrate another applicati n of a switch embodying my invention, the contacts 13 are not grounded as in the arrangement shown in Fig. 8 but instead are insulated and connected to suitable testing apparatus whereby the circuit 49 can be tested upon operation 0 the switch from one of its circuit closing positions, where the contacts 10, 11 are bridged, to the other circuit closing position, where the contacts 12,- 13 are brid ed.

ile I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown but seek to cover in the appended claims all those modifications that 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. An electric switch including a plurality of s aced pairs of contacts, a conducting mem r connecting one contact of one pair to one contact of another pair and means for bridging one pair of contacts at a time including a cooperating movable contact having a portlon adjacent said member, said portion being arranged for movement into contacting position between said member and each of the contacts connected thereby, and means for actuating said movable contact to bridge each of said pairs of contacts.

2. An electric switch including a plurality of spaced pairs of contacts, .a conducting member connecting one contact of one pair to one contact of another pair and means for bridging one pair of contacts at a time includmg a cooperating movable contact having a portion adjacent said member, said portion being arranged for movement into contactin position between said member and each 0 the contacts connected by the member, means for actuating said movable contact to bridge each of said pairs of contacts, and means for maintainin' the movable contact in one of its contact bri ging positions.

3. An electric switch including two spaced pairs of oppositely disposed contacts, a conducting member connecting two corresponding contacts of said pairs, and means for bridging one pair of contacts at a time including a cooperating contact movable between said two pairs of contacts and having a portion arranged for movement into contacting position between said member and each of the contacts connected thereby and means' for actuating said movable contact to bridge each ofsaid pairs of contacts.

4. An electric switch including two spaced pairs of oppositely disposed contacts, a conducting member connecting two' corresponding contacts of said pairs and means for bridging one pairof contacts at a time includin a cooperating contact movable between said two pairs of contacts and having a portion arranged for movement into contacting position between said member and each of the contacts connected thereby, said movable contact being constructed and arranged to pro vide a greater current carryin capacity in one bridging position than in t e other, and means for actuating'said movable contact to bridge each of said pairs of contacts.

' 5, An electric switch including two spaced pairs of stationary contacts, a conducting member connecting two corresponding contacts of said pairs and means for bridging one pair of contacts at a time including a cooperating contact movable between said two pairs of contacts and'having a bifurcated end portion straddling said member, the bifurcations of said portion being arranged for movement into contacting position between said member and the contacts connected thereby upon movement of said movable contact, and, means for actuating said movable contact to bridge each of 'said pairs of contacts.

6. An electric switch including two spaced pairs of oppositely disposed stationary jaw contacts, a straight conducting member extending from between the jaws of one contact of one pair to between the jaws of the corresponding contact of the other pair and means for bridging one pair of contacts at a time including a cooperating contact movable between said pairof contacts and having a bifurcated end portion straddlin said member, the bifurcations of said ortion being arranged on movement of saidbridging contact to move into contacting position between said member and the jaws of one of the contacts connected thereby and means for actuating said movable contact to bridge a pair of said. I

stationary contacts.

7. An electric switch including a luralone contact of another pair and'means for engaging one pair of contacts at a time including a cooperating movable contact having a portion adjacent said member, said portion being arranged for movement into contacting positionbetween said member and each of the contacts connected by the member, means operable when said movable contact is disenga ed from one of said pairs of contacts to ten to move the movable contact to en age the other pair ofcontacts. 8. 11 electric switch including a plurality of s aced pairs of contacts, a conducting mem r connecting one contact of one pair to one contact of another pair and means for bridging one pair of contacts cluding a cooperating movable contact having a rtion ad acent said member, said portion being arranged for movement into position between said member and each of the contacts connected by the member, and means for actuating said movablecontact to bridge each of said airsof contacts, said actuating at a time incontacting means inclu ing means for maintaining the movable contact in one. of its contact bridging positions.

9. An electric switch including a plurality of spiced pairs of contacts, a conducting mem r connecting one contact of one pair to one contact of another pair and means for bridging one pair of contacts at a'time including a portion ad acent said member, said portion being arranged for movement into contacting osition between said member and each of t'e contacts connected by the member, means for actuating said movable contactto bridge each of said pairs ofcontacts, and

means for biasing the movable contact for movement in adirection to bridge one of said pairs of contacts. a

I 10. An electric switch including relatively movable contacts and actuating means therer for including an operating vmember movable to a plurality of positions, means for permitting a limited movement of said member from one of said positions releasable when the member is in said one of said positions to permit a greater movement of the member and means for biasing said member for movea cooperating movable contact having ment from another of said positions when the 1 motion limiting means is released.

In witness whereof, I have hereunto set my 7 hand this 8th day of January 1931. v :HAROLD R. TURNER.

ity of spaced pairs of contacts, a con ucting member connecting one contact of one pair'to

Images