US1728829A - Electric switch - Google Patents

Description

Sept. 17, 192 9. J. D. HlLLlARD ELEGTiiIC SWITCH Fil ed April 30, 1925 FL I.

To Compressed /Air Sup ail; J

' Inventor John D.HLLLLC1PCL M 4v HLs Attorney Patented Sept. 17, 1929 UNITED STATES PATENT OFFICE- JOHN D. mLLIAnn, F SCHENEC'iADY, new YORK, ASSIGNOB T0 GENERAL ELECTRIC COMPANY, A CORPORATION on NEW YORK ELECTRIC SWITCH Application filed A ril 30, 1925. Serial No. 21,007.

My invention relates to electric switchesot the fluid break type and. particularly to switches of this type in which the circuit is broken by the downward movement of a movable contact. One object of my invention is to provide an improved construction of switch of this nature which is adapted for use in high tension service, has a large interrupting capacity and which requires the use of but a single insulating bushing. Another object is the provisionof means wherebythe movable contact can be completely withdrawn fron the bottom of the fluid tank and replaced if desired 'without disturbing the tank or withdrawing the fluid therefrom.

My invention will be better understood il'rom the following description taken in com 'nection with the accompanying drawing, and its scope will be pointed out in'the appended claims.

Referring to the drawing, Fig. 1 is a vertical sectional View of a fluid breakswitch illustrating my invention, and Fig. 2 is afragmentary view illustrating a modification.

From 'a suitable supporting structure 1 wvhich, for example, may comprise structural steelmembers, are shown depending a plurality of suspension insulators 2 of a type employed for supporting transmission lines, etc. The cover 3 oft-he switch tank 4 is supported by the insulators ":2 whence the tank is effectively insulated from the supporting structure 1. The tank 4 has a detachable bottom as shown and is secured to thecover in any desired manner but preferably by weld-i ing. The inner shell 5 is secured at the top to the cover 3 also preferably by welding and being open at thebottom forms'with the tank 4 a cushioning air space 6. The tank is otherwise filled with insulating fluid 7, as for example oil, and is provided in the cover with a float actuated valve 8 which operates automatically to release gases produced by the are drawn in the insulating fluid'upon the separation of the contacts. j

The switch according to'the embodiment of my invention illustrated is adapted to break the circuit at a single pointand accordingly has but one stationary contact and one movable contact. The single stationary-contact 9 is carried by the inner end of the insulator bushing 10 which is mounted in the cover 3, a circuit terminal 12 being secured to the outer end of the bushing. The movable contact rod 13 is reciprocally mounted in the bottom of the tank 4 and is electrically connected therewith hence the other circuit terminal of the switch. may if desired beattached directly to the tank as shown for example at H. A plate 15 having a suitable stufliug box 16 for the rod 13 is secured to the bottom of the tank so as to cover the enlarged opening therein. Tightly secured tothe inner face of the bottom of the tank is a. cap 17 through the crown of which is an opening for the free passage of the contact rod 13. This rod 13. by means hereinafter described. is adapted to be completely withdrawn from the tank for purposes of inspection. repair or re-, placement and in order to prey'eut the escape of insulating fluid at such times a flap door 20 is provided. This door has a suitable gasket on its face so as to seal the opening in the cap to prevent the escape of oil and is mounted on a short shaft journalled in the cap 17.

Tlie door is opened and closed by the hand -wheel 21" on the second shaft- .22 which ex-' tends through the tank and which is connect ed by gearing 23 with the shaft carrying the (1001'. For the purpose of insuring good contactbetwe'en the tank 4 and the rod 13 I have shown a. spring-pressed contact member 24 which preferably is segmental in form. the

segments being pressed against the rod by helical or by garter springs to insure good contact at all times with the rod.

For supporting the contact rod operating mechanism a stool 26 is provided having its legs bolted to the undr side of the tank bottom. The'openings between the legs facilitate accessto the stuffing box 16 as well as access to thebolts securing the plate 15 to the tank bottom. The cylinder 27 depends from the stool 26 and has the piston 28 mounted on the lower end of the rod 13. the latter passing through the stufiing box 29." The'bottom of the cylinder is closed by end head 39 which is readily detachable to permit the with 'drawal of the piston and contact rod. Air

pressure is preferably employed for operating box 16 and contact 24 may also then be removed.

I anismin addition to air supply through ing the movable contact rod andacco rding to the illustration, opposite ends of the cylinder are connected to a source of compressed the slide valve 40. The operating handle 41 of this valve may be operated manually or otherwise as desired. and may have an insulation section 42 interposed at some point therein. I

The operation of the contact operating means whereby the circuit is opened and closed will be obvious from the drawing, andthe description given above. H Should'the con'tactrod 13 become burned or should one desire to inspect this rod or the contact member 24, the rod is first moved to openiposition in which position the upper end of the rod still projects above the end of the cap 17. By removing the bottom cap 39 of the cylinder the piston 28 can be lowered until the end of the rod 13 is below the top of the cap 17.

Handle 21 is then rotated to close the door 20. tightly after which the piston and rod may be completely'removed. If desired, the stud- Furthermore, with the door 20 in its closed position the entire operating mechthe contact rod may be removed and subsequently replaced without the removal or the loss of the insulating fluid.

of, a fixed :contact mounted in the tank, iJcooperating contact rod mounted to slide 7 said opening, means external to the tank for moving the rod into and out of engagement with the fixed contact, said rod eing adapted to be com letely removed through said opening from the tank, a valve mounted within the tank, and means operable from the exterior ofthe tank for moving the valve to a position completely closing said opening to prevent the escape of liquid when the rod is removed. A

In witness whereoffl have hereunto set my hand this 29th day of April, 1925. 1

JOHN D. HTLLIARD.

In the modified form shown in Fig. 2 the inner shell 5 and the float actuated valve 8 are omitted, and an expansion space is maintained between the cover 3; and the level of the insulating fluid. The insulating bushing 44' is somewhat longer in this case and sur-- rounding that portion of the bushing which extends through the space' is a metal ground shield 45. The mechanism for operating the movable contact and for closing the opening iIp the bottom of the tank is the same as in ig. 1. While I have described only one embodi ment of myinvention, I do not wish to be limited to the particular form shown and de-. scribedas it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in the appended clanns.

What I claim as new and desire to secure by Letters Patent ofthe United States, is 2-- j 1. An electric switch comprising. a tank containing insulating liquid and having an opening in the bottom thereof, a fixed con tact-mounted in the tank, a cooperating mov-y.

able contact rod mounted to slide insaid opening, said rod being adapted to be completely removed through said opening from the tank, and a valve supported by the tank and arranged to be moved to a position completely closing the opening therein when the rod is removed'therefrom.

2. An electric switch comprising a tank 1 containing insulating liquid and having an opening in the bottom thereof, insulators supporting said tank from the top there-

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