US1708695A - Electric switch - Google Patents

Description

April 9, 1929; H. v. HAIGHT ELECTRIC SWITCH Filed Dec. 17} 1925 IN If EN TOR. 1 17a: r

f fd TTRNEY Patented Apr. 9, 1929 UNITED STATES PATENT OFFICE.

HARRY V. HAIGHT, 0F SHERBROOKE, QUEBEC, CANADA, ASSIGNOR TO INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTRIC SWITCB Application filed December 17, 1925. Serial No. 76,045.

This invention relates to electric switches adapted to carry very heavy currents, and its object is to extinguish the arcing at the switch contacts in a simple and effective manner.

The switch of this invention is adapted to be pneumatically operated. The exhaust air utilized in operating the switch is arranged to blow out the are between the switch contacts as they separate. In accordance with the practice of this invention means is provided to which the are is transferred from the switch contacts, which is so constructed that the arc thereafter dissipates and extinguishes itself without causing injury to the switch contacts.

Other objects and advantages of the inven tion will be in part obvious and in part pointed out hereinafter.

The invention will be more clearly understood by reference to the drawings, in which similar reference characters refer to similar parts, and which include Figure 1, a front elevation of a switch constructed in accordance with the practice of the invention; and

Figure 2, a vertical cross-section of the switch showing the switch operating mechanism and more particularly the arc extinguishing apparatus.

Referring to the drawings, the switch includes two sets of relatively movable electrodes, each comprising a stationary electrode A and a movable electrode B which are adapted to contact with each other to complete an electrical circuit. The contacts A are preferably rigidly mounted upon brackets C supported by insulating rods D extending preferably in a direction perpendicular to the contact faces of the contacts A. The contacts B may be mounted pivotally upon plungers E slidable within brackets F, also mounted on the rods D. Breaking of the electrical circuit is accomplished by separation of the switch cont-acts A and B, which is effected by lowering the plunger E.

The brackets O and F may be constructed of metal to act as terminals for electric cables G and H, whereby the current is supplied to the switch contacts A and B. To provide a solid contact between the brackets F and the contacts B flexible electrical conductors J may be bolted to rearwardly extending portions K of the switch contacts B and at the other ends to the brackets F. The brackets C and F are adapted to carry currents and are each provided with arcing horns L and 0 re spectively, which diverge from each other from points adjacent the switch contacts A and B. The arcing horns L and O are adapted to receive arcs transferred from the switch contacts A and B as the latter separate.

Due to the phenomena well known in the art,

an are between the arcing horns or electrodes L and O expands, and in a direction away from the switch contacts A and B, dissipating and extinguishing itself at the outer tips of the electrodes. The rods 1) are preferably mounted upon clamping brackets P and Q, in turn mounted on a panel or base R.

The relative movement of the switch contacts A and B is eficcted by means of a cylinder S, which may be formed integrally with the clamping bracket Q and provided with a piston T having a piston rod U extending in the direct-ion of the switch contacts B. Each of the plungers E is provided with a downwardly extending rod V connected with a cross head IV to which the piston rod U is bolted. The piston T is preferabiy pneumatically operated, and to this end a. valve X is provided in a pipe line. Y leading to a source of compressed air or other suitable gas (not shown). In the base Z of the cylinder S there is provided a passage 6 terminating in a valve seat 0. The base Z is provided with a cylindrical bore d in which a free floating piston valve 6 is adapted to reciprocate, having a groundseat f cooperating with the seat 0 to close thepassage b to the space above the pistin valve e. A bore 9 is provided longitudinally through the valve 6 to admit compressed air from the chamber below the piston valve, through the passage 6, into the interior of the cylinder S to force the piston T upwardly, to close the circuit of the switch contacts A and B. In its lowermost position the piston valve 6 seats upon a cap it closing the lower end of the cylindrical bore 03 to prevent the escape of air into the pipe line Y. In this position of the valve 6 exhaust motive fluid is permitted to escape through a passage j into a conduit is leading from the base Z of the cylinder S to a pair of nozzles 0 adjacent the the bore (Z of the cylinder base Z below the piston valve 6. The pressure of the entering air forces the valve 0 upwardly, closing communication at the seat 0 with the conduit Z2. Compressed air then passes through the bore y into the cylinder ta, forcing the piston T upwardly and through the piston rod U, closing the circuitthrough the contacts A and B and while the switch contacts A and B are closed no air escapes from the supply line Y. \Vhen the contacts A and l) are open no air, except that previously entrapped in the cylinder S, which is used to blow out the arc, can escape for the valve X closed. It itis desired to break the circuit between the contacts A and B, the valve X is turned to the position shown in Figure 2, whereat the supply of compressed air in the pipe Y is shut oil' and the pressure below the piston valve 6 is reduced by permitting the air to escape through a port p in the valve X to atmosphere. This causes the piston valve 6 to drop, sealing itself upon the cap it and preventing further escape of the air through the bore 9 to atmosphere by way of the valve. X. The valve 6 being removed from the seat 0, compressed air can then escape from the interior of the cylinder S through the conduit and out at the nozzles 0 adjacent the switch contacts A and B. Pressure in the cylinder S being released, the piston T will drop by gravity and with the assistance of a compression spring q, whereupon the switch contacts A and B separate. As is usual, an are forms between the switch contacts A and B but as the exhausted compressed air escapes from the nozzles 0 the arc is blown from the switch contacts A and B to the stationary electrodes or arcing horns L and O. Substantially no burning of the switch contacts A and 15 occurs, due to the cooling action of the air and the short duration of the are. The are between the electrodes L and O dissipates and extinguishes it self because of the divergence of the opposed faces of the electrodes.

1 claim:

A switch comprising a rod, a pair of. brackets having arcing horns fixed on the rod, a switch contact rigidly mounted on one of said brackets, a second contact movable with respect to said horn and guided by one of said brackets to cooperate with the other contact, a nozzle directed between said contacts and toward said arcing horns, and pneumatic means to actuate said movable contact member including a cylinder and piston associated with said movable contact member, a free floating valve for controlling the flow of mo tive fluid to said cylinder, and a conduit leading to said nozzle, said free floatingvalve being adapted to cut oil? communication between said motive fluid supply and said conduit while said switch is closed and to connect said cylinder with said conduit when the supply of motive fluid for said cylinder is cut ofl.

In testimony whereof I have signed this specification.

HARRY V. HAIGHT.

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