US1803163A - Electric switch - Google Patents

Description

pr 1931- H. N. BEEBE ELECTRIC SWITCH Filed June 12, 1929 2 Sheets-Sheet ln/rntow Hc "old N. Beebe, by 4%,

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April 28, 19 H. N. BEEBE ELECTRIC SWITCH Filed June 12, 1929 2 Sheets-Sheet In \fc-zntol" I Harold N. Beebe,

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Patented Apr. 28, 1931 UNITED STATES PATENT OFFICE HAROLD N. BEEBE, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCH Application filed June 12, 1929. Serial No. 370,206.

In low voltage alternating current distribution systems, the transformer stations at the ends of the feeder cables are located in vaults, the size of which is restricted by eco- 13 nomic factors and underground congestion.

- Moreover, it is often necessary, particularly in congested districts to use existing vaults which were not builtto meet the demands of system changes and better service. Inas- 1; much as the feeder circuits are operated at relatively high voltages, ranging from 4,000 to 26,000volts, the necessary insulation in view of the space limitations is of great importance especially for switches. If an insulati'ng fluid such as oil is used for the switches, it must not be allowed to escape and thereby affect the'insulation and create a fire hazard. Because of the probability of dampness and even flooded conditions of the vaults, water must'be kept from the switch parts and the insulating fluid. Moreover, in order to insure safety and convenience for testing, operation and maintenance, the switch apparatus must be safely accessible and ar- 33 ranged to prevent improperor dangerous operation.

- It is then an object'of my invention to provide an improvedand simple switch which is compact and yet conveniently accessible and which is fluid tight. Another object is to provide an improved switch which is suitably insulated for the desired voltages. A further object is to provide an improved switch which insures a high degree of safety for both apparatus and operator under normal operating conditions and particularly during testing and maintenance.

My invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the accompanying drawings, Fig. 1 is a front elevation of a double-throw switch embodying my invention, the switch being shown in one of its circuit closing positions; Fig. 2 is a part sectional elevation on the line 22 of Fig. 1 with the switch in the same position as in Fig. 1; Fig. 3 is similar to Fig. 2 except that the switch is shownin the circuit opening position; Fig. 4 is similar to Fig. 2 except that the switchis shown in its other circuit closing position; Figs. 5, 6 and 7 are perspective views of a part of the operating mechanism of the switch shown in Fig. 1 with the parts positioned to correspond with the conditions in Figs. 2, 3 and 4 respectively; Fig. 8 is a transverse sectional elevation of the operating mechanism with the parts positioned as shown in Fig. 6; Fig. 9 is a perspective view of the switch shown in Fig. 1 with parts omitted for the sake of clearness; and Fig. 10 is a circuit diagram illustrating an application of the switch shown in Fig. 1.

The embodiment of my invention chosen for the purpose of illustration is a three-phase double-throw switch including two relative sationary spaced contact means such as front and back contacts 11 and 12 respectively and a cooperating movable contact means such as the contacts 13. The contacts 11 have terminals 14 and are mounted in insulators 15 supported on a member 16. As shown this member, which may be of insulating material, extends between the end plates 17. The

contacts 12 may be similarly mounted but in order to use the switch for groundlng purposes they are shown as mounted on a cross member 18 of electric current conducting material. This member is arranged to be grounded through a flexible lead 19 and screw connection 20 to the switch chamber or housing 21 which is cut away for clearness in showing the switch parts.

Inasmuch as the usual insulating materials are not well adapted to withstand torsional stresses and to obtain the necessary strength would mean undesirable bulk, I provide in accordance with myinvention an arrangement for actuating the movable contacts 13 whereby to insure both strength and insulation without bulk. As shown this arrangement includes a contact supporting member 22 which is of insulating material such as a shaft 23 at the ends of a crank or cranks 24 secured thereto. The shaft 23 is journalled on .the end plates 17 and may be of any suitable metallic material for torsion stresses and, if desired, may be provided with a coating or layer 25 of insulating material for further safety.

In orderto lock the switch in its different circuit controlling; positions, the extension of the shaft 23 through one of the end plates 17 may be provided with interlocking means shown as of the bar and sector type, the bar 26 being arranged to be actuated by .suitable electromagnetic means 27 and to engage slots in the sector 28 which is secured to the shaft. v

In order to control the angular position of the movable contact supporty22 as the shaft 23 is rota'tedand the contacts 13 are moved from a positionadjacent one set of stationary contacts to a position adjacent the other set so as to insure proper register with these contacts, I provide in accordance with my invention relatively movable guiding elements such as an arm or arms 29 extending from the member 22 and engaging guides 30 on the end plates17, the engagement with theguides being such as to permit the desired angular movement ofthe arms. For this purpose the guides may have suitably shaped and enlarged openingsor a swivel mounting may be used. The movable contacts 13 are con -nected through flexible leads 31 to entrance also serve'as adjustable members to tie the end plates together at the bottom, as shown. In order to mount the switch relatively to its" casing for easy withdrawal-and replacement, the casing and walls 21, as shown in Fig. 1, may be provided with angle shelves 35. In these are mounted set screws 36 which engage the end plates 17 or projections thereon so as .to determine the position of the switch in its casing. Suitable fastening means such as bolts 37 extend through the shelves into theend plates 17. Obviously, on withdrawal of these bolts, the end plates are movable relatively to the casing 21 and with the switch in the open position shown in Fig. 3 and upon release of the electrical connec tions including the ound connection 19, 20; the connections to t 1e terminals 14, the conmotions of the flexible leads 31 to the bushings 32, and the auxiliary circuit conductors 38 of the electromagnetic locking means 27, the switch be withdrawn from its casing.

If the adjustment of the set screws 36 is not disturbed, replacement is readil possible or adjustment can easily be made if necessary to lineup the witch relatively to its casing.

Further, i accordance with myinvention, I provide a switch operating means 40 whereby the switch may be locked in any of I its circuit controlling positions and whereby movement from one circuit closing position through the open position to the other closed position cannotbe made without some forethought on the part of the operator. The operating means 40 also includes means for maintaining a substantially fluid tight seal about the part of the operating mechanism which projects through the casing 21. As shown, the operating. means includes a base 41 which is secured to the casing 21 by suit- I .any one of its positions, I provide a locking member'48 which is pivoted on the base 41 and is provided with alocking lug 49. In the open position of the switch, the locking lug 49 is arranged to be entered into a slot 50 in the operating member 44 and in either of the closed positions of the switch the locking lug 49 can be placed in the path of movement of one or t e other of the lugs 51 on the operating member 44. Looking eyes 52 on the base 41 and the locking member 48 come into register when the locking member is in locking position and a padlock 53 may be inserted to prevent unauthorized operation of the switch.

While the shaft portion of the operating member 44 passes through suitable packing and a gland bushing54, this must not be so tight as to prevent or make difficult the rotation of the shaft 23 and yet the switch casing must be maintained fluid tight from both within and without I further provide in accordance with my invention for obtaining this fluid tight seal an arrangement which can he released to permit rotation of the op-. erating 'member 44 when desired and yet maintain an effective seal at all other times. For this purpose Iprovide an additional packing means such as a gasket 55 where the shaft portion 45 extends through the base 41 arranged so that the locking member 48 ma be operated to perform not only its loc ing function but also the necessary sealing function as this insures simplicity of the apparatus. For this purpose the locking member is provided with an eccentric or cam portion 56 which engages the outer extremity of the shaft portion 45.- With the locking member in the position shown in Figs. 5 to 8 inclusive, the cam exerts considerable pressure onthe shaft portion 45 thereby compressing the packing 55 around the shaft.

Upon counter-clockwise rotation of the lockthe movement of the operating member 44 fromone of the circuit closing positions as shown in Fig. 5 to the circuit open position shown in Fig. 6, whereby the operating member cannot be moved to the other cir cuit closing position shown in Fig. 7 without returning from the circuit open position to the circuit closed position shown in Fig. 5 and performing in this position a special operation. As shown, this motion limiting means includes a locking element 57 pivotaily associated with the operating member 44 at 58. The locking element 57 carries at its other end a projection such as a pin 59 which projects through the slot 50 in the operating member into a cooperating interlocking element such as the slot 60 in a raised portion of the base 41. This slot 60 is open atone end and closed at the other end and of such length as to permit the illustrated embodiment of my invention substantially a 90 movement of the operating member as will be more clearv 1y apparent from Fig. 7, that is from the position shown in Fig. '5 to the position shown in Fig. 6. In order to permit the rereleasing movement of the member 57, the end pivoted to the operating member 44 includes a lost motion slot. The open end of the slot 60 is such that the pin 59 in the limiting link 57 can be withdrawn from the slot 60 by movement in the slot of the op crating member 44 only when the operating member 44 is in the position shown in Fig. 5. This is the position corresponding to engage? ment of the contacts 13 with the contacts 11.

In the schematic circuit arrangement shown in Fig. 10 to illustrate an application of a switch embodying my invention,-a polyphase high voltage feeder 61 is connected to a low voltage network 62 through the contacts 11, 13 of a switch suchas shown in Fig. .1, a step down transformer 63 and a circuit breaker 64. The electromagnetic inter.- locking means 27 may be connected across a phase of the network as shown, so that whenever the circuit breaker 64 is closed and the network is energized, or the feeder is energized, the electromagnet 27 wili be excited to lock the switch sector 28 so as to prevent operation of the switch 11, 13 on a 'iive circuit.

This insures the operators safety since it is thus impossible to open the disconnecting switch 11, 13'under load.

1 Assuming that the feeder disconnecting switch is in the circuit closing position, that is, that the contacts 11 and 13are in engagement and that the circuit breaker 64 is closed and either the feeder 61 or thenetwork 62 or both are energized, it will be impossible to turn the switch since the electromagnetic means 27 is energized and engages the interlocking sector 28. Under these conditions the switch parts are positioned as shown in Figs. 1, 2, 5 and 9. If for any reason it is desired to work on any of the equipment in the vault or chamber containing the transformer 63 the circuit breaker 62 and the disconnecting switch, the operator must first arrange to have the feeder circuit 61 opened, for example, at the power 'station and must eifect the opening of the circuit breaker 64. The electromagnetic means 27 is thus deenergized and the locking sector 28 released. Whoever is authorized may unlock the padlock ,53 thus unlocking the operating mechanism 40. Even though this mechanism were not unlocked prior to the opening of the circuit breaker 6'4 and the feeder circuit 61, it would still be impossible to move the operating handle since the interlocking means 26, 27 and 28 would be engaged. Assuming, however, that this interlocking means is released, then the operating handle 44 can be moved into the circuit open position shown in Fig. 6 after counter-clockwise movement of the locking element. 48 whichm'oves the lug 49 out of the path of movement of the lug 51 as will be obvious from Fig. 5, and releases the pressure on the packing 55. The operating handle 44 'may'then be moved into the position shown in Fig. 6, and, if desired, locked in this position by turning the locking element 48 clockwise into the position shown in Figs. 6 and 8 with the locking lug 49 in the slot 50 on the operating handle 44. In this position the padlock 53 may again be inserted in the registering eyes 52 if it is desired to lock the switch against unauthorized use.

If the switch is moved to the open position shown in Figs. 3, 6 and 8, and left in this position with the locking element 48 in the locking position with pressure on the packing 55, it may be that an operator or maintenance man might come along and release the member 48 and try to move the operating handie to the ground position. This, of course, cannot be done if the electromagnetic interlock 27 is energized. If, however, the switch is in the open position and the circuit breaker 64 is open and in the meantime the feeder 61 has been energized for example by closing the switch the power station, then the interlocking means 27 would be deenergized and if the operating member 44 could be moved to the ground position a polyphase I ice short circuit would be put on the live feeder 61. This, of course, must not be'done. If under these conditions the operator attempts to more the contacts 13 to the ground position he will find it impossible to do so since the pin 59 in the link 57 comes to the closed end of the slot 60 when the operating member 44 is in the switch open position. Consequently, the operating handle must be moved from the open position back to the closed position shown in Fig. 5 before the pin 59 can be released from the slot 60. However, when the operator makes this closing movement of the operating member 44-if the feeder 61 is energized the electromagnetic interlock 27 will be excited even though the circuit breaker 64 is open. Consequently, as soon as the switch is returned to the closed position it will be locked there by the electromagnetic interlock and the operator will be unable to move it from this position. If, however, the feeder 61 were not energized and the circuit breaker 64 were open when this return movement to iheclosing position is made, the operating handle would be free for movement to the ground position upon n'ioving'the link 57 so that its pin 59 moves outward in the slot 50 and away from the slot 60. The operating handle may then be moved substantially 180 to the position shown in Fig.7., This is the grounding position of the switch with the contacts 12 and 13 in engagement, as shown in Fig. 4. In this position of the switch the return of the locking element 48 to the position shown in Fig. 7 restores the pressure about the shaft extension 45 and puts the lug 49 in the path of movement of the lug 51 on the operating member 44, and if desired, the switch may be locked in this position by inserting the padlock in the eyes 52. Upon the release of the locking lever 48, theswitch can be returned from the ground'position to the open position, but cannot be locked in this position since the link 57 will be in the path of movement of the lug 49. This will be apparent from 8, for the pin 59 will be in the lug 65 in line with the lug 49. In order to lockthe switch in the open position the operating member 44 must be returned to the closed position, as shown in Fig. 5, where the pin 59 will automatically-engage the slot 60. This automatic return is due to gravity when the operating mechanism is mounted as shown in Fig. 1, but it will be apparent that any other suitable biasing means could be employed.

lVhile Ihave shown and described my invention in considerable detail, I do not deire to be limited to the exact arrangements shown but seek to cover in the appended claims all those modificaions thatfall within the true spirit and scope of my invention.

VVh-at I claim as new and desire to secure by Letters Patent of the United States is 1. An electric switch including relatively movable contact means and actuating means therefor including an operating member movable to a plurality of positions and means for permitting a limited movement of said member from one'of said positions including a locking element mounted on said member for movement relatively thereto, said element being releasable only when the member is in said oneof said positions to permit a greater movement of the member.

2. An electric switch including relatively movable contact means and actuating means therefor including an operating member movable to a plurality of positions and means for permitting a limited movement ot'said member from one of said positions including relatively movable interlocking elements rcleasable only when the member is in said one of said positions to permit a greater movement of the member. 3. An electr1c switch mcludmg two relatively stationary spaced contacts, a cooperating movable contact, and actuating means therefor including a rotatable operating member, an insulating support for said movable contact pivotally mounted on said operating member and relatively movable guiding elements for controlling the angular po sition of said support on rotation of said operating member to actuate the movable contact from a position adjacent one of the stationary contacts to a position adjacent the other stationary contact, one of said elements being secured to said support.

4. An electric switch including relatively movable cooperating contacts and actuating means therefor includinga rotatably mounted operating member, an insulating member for supporting one of said cont-acts pivotally mounted on said operating member and relatively movable means for controlling the angular position of the insulating member.

5. In an electric switch having relatively movable contacts mounted in a chamber, switch operating means including a member extending into the chamber, and means for maintaining a substantially fluid tight sval about said member arranged to be actuated to scaling position when the member is in a predetermined position and when in the sealing position to prevent the movement of the member. 1

6. An electric switch including relatively movable contacts and actuating means therefor including an operating member 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 adapted to be operated when the member is in any one oi said positions to lock the member against movement.

7. An electric switch including two relatively stationary contact means and a fnovable contact means arranged to be positioned to engage either of said stationary contact means, means for actuating the movable contact means including an operating member arranged on movement in one direction to disengage the movable contact means from one of the stationary contact means, means for limiting the movement of the operating member in said direction whereby to prevent engagement of the movable contact means with the other stationary contact means, releasable to permit sai "engagement only when the movable contact means is in engagement with said one of said contact means.

8. An electric switch including two relatively stationary spaced contact means, a cooperating movable contact means, and actuating means therefor including ashaftmounted between said stationary contact means, a crank on said shaft, an insulating support for said movable contact means pivotally mounted on said crank whereby on a predetermined rotation of said shaft the movable contact means is moved from a position adj acent one stationary contact means to a position adjacent the other stationary contact means, and means for controlling the angular position of said support including an arm extending from the support and a guide for the arm.

9. An electric switch including two rela--- .means inqlud'ing ,a member extending into the fiuid containing chamber and movable to a plurality of positions, means for permitting a limited movementof said member from one of said positions releasable when the member is in said positions to permit agreater movement of the member, and means for maintaining a substantially fluid tight seal about said member arranged to be actuated to sealing position when the member 'is in one of sad positions and whenin the sealing position to prevent movement of the member.

11. An electric switch including relatively movable contact means and actuating means therefor including an operating. member movable to a plurality of positions and means for permitting a limited movement of said member from one of said positions including relatively movable elements respectively provided with a slot and a projection mounted for movement in the slot, said projection being removable from said slot only when the operating member is in a predetermined position to permit a greater movement of the member.

12. An electric switch including relatively movable contact means and actuating means therefor including an operating member mov- In Witness whereof I have hereunto set my hand this 10th day of June, 1929.

' HAROLD N. BEEBE.

CER'liFiCA'lE @F CORRECTION.

Patent No. 1,803,163. Granted April 28, 1931, to

HAROLD N. BEEBE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, line 51, claim 10, before "positions" insert the words one of said; 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 2nd day of June, A. l). 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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