US1821414A - Electric circuit-breaker - Google Patents

Description

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Sept. l, 1931. A. ALLAN ELECTRIC CIRCUIT BREAKER Filed Jan. 25, -1950 Patented Sept. 1, 1931 UNITED STATES PATENT oFFiCE ARCHIBALD` ALLAN, F TYNEMOUTH, ENGLAND, ASSIGNOR TO A. REYROLLE & COM- PANY LIMITED, 0I' HEBBURN-ON-TYNE, ENGLAND, A COMPANY OF GREAT BRITAIN ELECTRIC CIRCUIT-BREAKER Appiicatidn med January 25, 1930, serial No.

This invention relates to electric circuitbreakers and more particularly to the contactsthereof. v

The object of the 1 invention is the conu struction of an improved form of contact of the general type in which a spring-pressed arcing contact is arrangedy to slide relatively to one or more main contacts.

A Contact for an electric circuit-breaker according` to the present invention comprises one or more main contacts, an arcing contact slidable axially against the action of a spring in guides which form supports for the main contacts, and a dashpot having a piston which towards the end of the closing movement of the circuit-breaker is moved inwards in the dashpot by the movement of the sliding contact.

fThe improved contact is primarily intended for use in an oil-immersed circuitbreaker, vand one construction is illustrated in the accompanying drawings, in which Figure 1 is an elevation with the casing in section,

Figure 2 is a vertical central section on the line 2-2 of Figure l,

Figure 3 a view similar to Figure 2 but with the parts in a position which they occupy during part of the closing movement 3o of the circuit-breaker, and

Figure 4 is a sectional plan on the line 1 -4 of Figure 1.

Like letters indicate like parts throughout the drawings.

In these iigures, the blocks A, of which there are six, constitute one of the main relatively fixed contacts of an oil-immersed circuit-breaker. The cooperating movable contact is shown only in Figure 3 at B.

The main contact blocks A are supported on springy arms as at A1 on a block C1 forming part of a slotted tube C attached to or integral with a iixed plate D to which one of the conductors (not shown) lead- 15 ing to the circuit-breaker can be connected by the clamp E.

Slidable in the block C1 is an arcing contact F having a head F1 which is screwed into a crosshead G guided in the slotted tube 56 C and electrically connected to the plate D 423,443, and in Great Britain March 26, 1929.

by flexible conductors G1. A spring H encircles the slotted tube C between the fixed plate D and the crosshead G, thus exerting a pressure which tends to keep the crosshead and arcing contact down in the positions shown in Figures l and 2.

Fixed in the upper part of the tube C is a dashpot J having sliding within it a piston J1 pressed down by a spring K. There is a small outlet for oil from the dashpot through a screwed plug L passing through the plate D. To this plate D is secured a shield or casing M which surrounds all the parts and extends down. somewhat below the main contact blocks A. As will be seen by reference to Figure l, the shape and disposition of the parts are such that in the open position of the circuit-breaker the lower ends of the shield M and the slidable arcing contact F are bounded by an imaginary sphere indicated by the line X.

The block C1, as may be seen from Figure l, is in this example hexagonal for convenience in attaching to it the arms and springs which support the blocks A.

The movable main contact B is not shown in Figures 1 and 2 where the relatively fixed main contacts A and the arcing Contact F are in the open position. In Figure 8 the movable main Contact B has been brought upwards in the usual closing movement of the circuit-breaker and, as shown, it has pressed the sliding arcing contact F upwards through its guide block C1 and is beginning to spread the main contact blocks A. This upward movement of the arcing contact has carried the crosshead G upwards in the slotted guide tube C against the action of the spring H and the'head F1 has pushed the piston J1 up into the dashpot J against 90 the action of the spring K. This movement is not necessarily complete in the position shown in Figure 3 but may be continued somewhat further according to the upward travel of the movable main contact B. As the hole in the plug L is small an effective cushioning or dashpot action is exercised on the moving parts towards the end of the closing movement of the circuit-breaker. On

J(he opening movement the arcing Contact m" can, under the action of the spring H, follow freely the downward movement of the main contact B as it is independent of the dashpot and its piston.

It is to be understood that the construction illustrated is given by way of example and that details may be varied within the scope of the invention as set forth in the appended claims. y n

That I claim as my invention and desire to secure by Letters Patent is 1. In an electric circuit-breaker a contact comprising an arcing contact slidable axially in a guide or support, at least one main contact mounted on said support, a spring acting on said arcing Contact, a dashpot in the path of motion of the arcing contact, and a piston in said dashpot said piston being separate from the arcing cont-act so that it is engaged and moved inwards in the dashpot towards ythe end of the closing movement of the circuit-breaker but permits free movement of the arcing vcontact during the opening ot' the circuit-breaker.

2. In an electric circuit-breaker an arcing contact slidable axially in a slotted support, a plurality of spring-mounted main contacts attached to said support, a crosshead on said arcing contact and guided in the slots in said support, a spring acting on said crosshead, a dashpot in the path of motion of the arcing contact, a piston in said dashpot, and a spring acting on said piston said piston being separate from Vthe arcing cont-act so that it is engaged and moved inwards in the dashpot towards the endV of the closing movement of thel circuit-breaker but permits free movement of the arcing contact during the opening of the circuit breaker.

3. In an electric circuit-breaker a contact comprising a supporting plate, a slot-ted guide attached to said plate, an arcing contact slidable axially in said guide, a plurality of spring-mounted main contacts surrounding said arcing contact, a crosshead on said arcing contact and working in said slotted guide, a spring acting on Said crosshead, a dashpot in the path oi motion of the arcing contact, a piston in said dashpot, a spring acting on said piston said piston being separate from the arcing contact so that it is engaged and moved inwards in the dashpot towards the end of the closing movement of the circuit-breaker but permits free movement of the arcing contact during the opening of the circuit breaker, and flexible connections between said cross* head and the supporting plate.

4. In an electric circuit-breaker an arcing contact slidable axially in a slotted support., a plurality of spring-1nounted main contacts attached to said support, a crosshead on said arcing contact and guided in the slots in 5 said support, a spring acting on said crosshead, a dashpot in the path of motion of the arcing contact, a piston in said dashpot, a spring acting on said piston said piston being moved inwards in the dashpot towards the end of the closing movement of the circuit-breaker, and a casing surrounding the contacts and having an open end extending almost to the lower end of the arcing contact so that in the open position of the circuit-breaker the lower ends of the casing and arcing contact are bounded by the surface of an imaginary sphere.

5. In an electric circuit-breaker a contact comprisingV a supporting plate, a slotted guide attached to said plate, an arcing contact slidable axially in said guide, a plurality of springLmounted main contacts surrounding said arcing contact, a crosshead on said arcing contact and working in said slotted guide, a spring act-ing on said 'crosshead, a dashpot in the path of motion of the arcing contact, a piston in said dashpot, a spring acting on said piston said piston being moved inwards in the dashpot towards the end of the closing movement of the circuit-breaker, flexible connections between said crosshead and the supporting plate, and a casing surrounding the contacts and having an open end extending almost to the lower end of the arcing contact so that in the open position of the circuit-breaker the lower ends of the casing and arcing contact are bounded by the surface of an imaginary sphere.

In testimony whereof I have signed my name to this specification.

ARCHIBALD ALLAN.

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