US1621369A - Electric switch - Google Patents

Description

March 15,1927.

J. D. HILLIARD ELECTRIC SWITCH Filed Nov. ll, 1922 Inventor: John D. Hilliamd.J

His Attovheg Patented Mar. 15, 1927.

UTS STTS JOHN D. I-LLIARD, GF S -ENECTADTZ.

PATENT FFICE.

i TEW "202K, AESSG-NGR 1"0 GENERAL ELECTRIC CGIVIEANY, t CGRGRATON OIE' NEW' YGRK.

Application filed November My invention pertains to electric switches 4and in particular to improved means for type, when the contacts are separated. an arc is drawn in the liquid and part ot the liquid is vapori/ced and disassociated, suddenly producing gases at such high pressure as to stress the tank ot the switch. The amount ot gases formed and consequently the pressure generated depend among other things7 on the lengt-h ot time during which the arc is maintained. his time will be largey determined ly the interval required tor the contacts to separate the required breaking distance.

lne object ot' my invention is 'therefore to provide in an electric switch improved means for accelerating the movement of the circuit interrupting contacts.

Another object of my invention is to provide in an electric switch improved means for limiting the gas formation when an arc is drawn in a liquid upon the opening of the separable contacts.

A further object et my invention is to provide improved means tor locking the contacts of an electric switch against the magnetic repulsion caused by the current flowing through said contacts.

Other objects and advantages will appear trom the following description ot' my invention when taken in connection with the accompanying drawing in the single figure of which is illustrated a single pole switch of the fluid break type shown partly in elevation and partly in section, some ot the parts being broken away.

Referring more. particularly to the drawing7 there will be seen a switch trame 1 adapted to support insulating bushings 2 which are held in place by clamping plates 3. Stationary electrodes l pass through and are fastened to the insulating bushings 2. The stationary electrodes d are adapted to support primary contact brushes 5 and secondary contact members 6.

A tank .7 having` an insulating lining 8 is supported from the switch iframe 1 and is adapted to contain an insulating` liquid 9, the normal height ot' which is indicated by the shading.

A link 10 is connected with any suitable operating means (not shown but which may 1, 1922. Serial No. 668,290.

:tor example be similar to that shown in U. S. Letters Patent No. 942,491, to W. L. R. Emmet and E. lll. Hewlett dated Dec 7, 1909) and the toggle 11 to produce movement ot a contact lever 12 to which an operating rod 13 is connected. The operating rod 13 passes through an aperture 14 in the switch :trame 1 and supports a primary bridging member 15 to open or close the circuit at the primary brushes Rods 16, which l: term accelerating members7 are pivotally attached to the primary bridging member 15. Conductors 17 are provided for the purpose ct insuring good contact between the bridging member 15 and the secondary contact members 19.

An insulating secondary Contact support 18 is attached to the switch trame 1 and is arranged to pivotally support the secondary Contact members 19, Electrical connection between the secondary contact members 19 is maintained by a flexible connection 20. Pins 21 attached to the accelerating members 16 are adapted to engage the secondary contact members 19. The movable secondary contact members 19 are adapted to engage with the secondary contact members 6.

The secondary contact levers 19 are maintained in closed position by means of a restraining block 22 fixed to an extension 23 of the operating rod 13 and adapted to cooperate with one end of each of these levers. The springs 2aprovide a resilient connection between the secondary contact levers 19 and the accelerating members 16.

Operation trom the closed position ot the switch follows: Automatic or manual tripping of the operating means causes downward movement ot the operating rod 13 breaking contact between the primary brushes 5 and the primary bridging member 15, the secondary contact members 19 being held in engagement with the secondary Contact members 6 by the pressure of springs 24 and restraining bloc r 22 until the restraining block 22 has cleared the lower ends of the secondary contact members. Further movement of the operating rod 13 will cause the pins 21 in the accelerating member to engage with the secondary contact members 19 and cause their disengagement with the secondary contact clips 6 to make the final break in the circuit.

The primary brushes 5 are usually made of strips of copper or copper alloy which has a low elastic limit and the resiliency of which may be destroyed by heating due 'to brush contact resistance. With the disclosed arrangement of parts, the magnetic brushes.

The secondary contact members 1S are locked in closed position against the action` of the magnetic field of the switch by means of the member 22 and are operated in i' sponse to downward movement of the primary bridging member 15. Due to the fact that the actuating force is applied to the members 19 at a point near their pivota connection with the fixed insulating` member 18, the contacting parts of these members are moved at a speed greatly in excess ot that at which the primary bridging member itself moves. This serves to quickly break the circuit and prevent the formation of destructive arcs.

In closing, the springs 2t which are under compression between the accelerating' men bers 16 and the secondary contact members 19 cause the secondary contact members to follow the upward movement of the accelerating members and clear the passage for the restraining bloclr 22 to enter between the lower ends of the secondary contact members 19 and lock them in the closed position. Further upward movement of the operating' rod 13 will establish a primary circuit by the engagement ot' the primary brushes 5 with the primary bridging member 15.

My invention may be embodied iii other forms than that shown and described, and is, therefore, not restrict-ed to the construction shown but comprises all changes and` modifications which come withinthe spiritand scope of my invention as indicated by the appended claims.

lVhat l claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a switch, a plurality of stationary contact members, a movable bridging contact member, pivotally mounted secondary contact members, means associated with said bridging member' for moving said secondary cbntact members to closed circuit position vand for locking the saine in said position,

and means movable with said bridging member in its circuit opening movement tor engaging said secondary contact members at points adjacent their pivotal centersv for rapidly moving said members to open circuit position.

2. An electric switch comprising a pair of fixed main contacts, a bridging member adapted to engage said contacts, a. pair of fixed secondary contacts. movable contact members connected together and arranged to bridge said secondary contacts, and a loclring member movable with said bridging member, said locking member being arranged to have sliding engagement on opposite sides with said contact members when the bridging member is initially moved from closed circuit position for holding the contact members locked iii closed circuit position.

An electric switch comprising fixed main contacts. a bridging member adapted to engage said contacts, an operating meinber therefor, fixed secondary contacts, a support, a pair of secondary contact arms pivoted thereto at iixed points, anopeiat` ing connection between the bridging member d each of the secondary Contact arms. and a locking member operatively connected to the bridging member for locking the contact arms in closed circuit position, said locking member having a limited movement while maintaining the contact arms in locked circuit closing position.

et. rin electric switch comprising fixed main contacts, a bridging member adapted to ene' 'le said contacts, an operating member thei et'ci', fixed secondary contacts, a. support, a pair of secondary contact arms pivoted to the support at fixedV points and adapted to engage said secondary contacts, said contact arms having locking extensions thereon, and a locking member movable with said bridging member and having sliding engagement with said extensions for holdr the arms in Contact with the fixed secondary contacts throughout 'a predetermined of movement ot' the bridging member.

5. An electric switch comprising fixed main contacts, bridging member adapted to engage said contacts, an operating member therefor, fixed secondary contacts, a support, a pair of spaced secondary contact arms pivoted thereto Vand each having a loclring extension, and a locking` member carried by the bridging membei1 between said locking extensions and arranged to maintain said extensions in spaced'relation when the rid ing member is in a predetermined posit on, thereby locking the contact arms in contact w th the fixed secondary contacts. in witness whereof, l have hereunto set my hand this 9th day of November, 1922.

SGEN l). HILLARD.

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