US1854990A - Electric switch - Google Patents

Description

April 19, 1932. J. D. HILLIARD ELECTRIC SWITCH Filed July 1, 1929 InventoP John D- H L LLLar'd,

HLS Attorneg.

Patented Apr. 19, 1932" UNITED STATES PATENT OFFICE JOHN D w, OI BCHRI EGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION 01!? NEW YORK ELECTRIC SWITCH.

Application filed July 1, 1929. Serial 'No. 875,141.

My invention relates to improvements in electric switches and more particularly switches for closing a circuit subject to large currentsespecially in case of abnormal cir- 6 cuit conditions. Circuit closing switches may'be used to avoid contactdestruction as disclosed in United States Letters Patent 1,546,172, dated July 14, 1925 and showing two switches in series, one to interrupt and N-the other to close a circuit. The closing switch may be subject-tosevere service particularl under overload and fault cond1- tions. in fact the electromagnetic stresses may be so great as to cause distortion of the 1 switch arts and attached conductors and even su cient to prevent closing the switch or to cause-it to open immediately contact occurs. An object of my invention is to provide an improved high pressure contact switch in which the electromagnetic forces involved tend to close the contacts and maintain them closed whereby the switch closing operation is :facilitated and the necessary contact pressure assured. Another object of 95 my invention is to provide an improved switch structure whereby to prevent deformation of the parts under the electromagnetic forces involved. F

My invention will be better understood 80 from the'following description when considered in connection with the accompanylng drawings and its scope will be pointed out in the appended claims.

- In the accompanying drawings Fig. 1 is a side elevation of an electric switch embodying my invention; Fig. 2 is a sectional elevation on the line 2-2 of Fig. 1; and Fig. 3 is a sectional elevation onthe line 3-3 of n the electric switch chosen to illustrate m invention, a conductor 100 10 is mounte on and insulated from suita le supporting means such as a station partition wall or a switch board' 11 and a bracket 12 secured thereto. The loop "10- is more or less U- shaped and includes two relatively movable cooperatingcontacts. such as the fixed contact 13 and a movable contact 14 mounted on the free end of a switch blade 15 which is pivoted at 16 as shown. In order to facililel portions of the loop 10. Inasmuch as current flows in opposite directions in these two portions, the tendency is for them to separate or the loop to straighten so that a pressure dependent on the current is maintained at the contact-surfaces which as shown are of the high pressure line contact type. Qbviously, if the switch is used to close a circult in conjunction with another for opening the circuit as disclosed in the patent previously mentioned, then on moving the blade 15 to engage the contact 13, the electromagnetic forces assist the closing operation.

In order to prevent distortion of the loop 10 under the electromagnetic stresses due to large currents, I provide a holding means which as shown includes two insulated tie rods 18 which engage the bracket-12 and a yoke 19 secured to an insulator 20 on the conductor portion 17. In this manner the insulator 20 is under compression while the rods '18 take the tension so that the materialsare used to withstand the stresses for which they are best adapted. The conductor loop leads 21 and 22, one of which such as 21, goes to the circuit opening switch are supported on insulators 23, 24. The lead 21 which mayform apart of one leg of the loop 10 has mounted thereon the contact- 13 and the insulator 23 is of course under compression for which it is suited. The base ofthe loop including the switch hinge is mounted on an insulator 25. The number of conductor sections or bars is, of course, a matter dependent on'ithe curgrant to be carried. The switch hinge includ ing the pivot may be provided with resilient means such as a spring 26 for. insuring the necessary contact pressure between the laminations of the hinge part 27 of the loop and the blade 15. In order to prevent cutting at the hinge, suitable means such as grooves 28 for the reception of vided.

In order to open and close the switch any suitable operating mechanism may be provided. This will in general be so interlocked with the circuit opening switch as to secure the proper sequence of operation as disclosed in the patent previously mentioned. The operating mechanism shown includes an op: erating member suchas a shaft 29 to which the blades 15 of the different poles of the switch are connected by rods 30. The shaft may be biased for circuit opening movement by a spring 31. For closing a solenoid 32 may be provided. The shaft may be locked in the circuit closing position by a latch *33 under the control of a trip coil 34. The circuit of the closing solenoid and trip coil may be controlled by switches 35 and 36 respectively arranged to be operated in any suitable manner.

Switches of the type embodying my invention may be used in arrangements where the phases are isolated by walls or partitions. Thus the switches may be double or triple pole with the poles in the different phases separated by walls 37 as indicated in Fig. 2. In this case, a short-circuit for example may mean large currents in opposite directions in two adjacent switch blades 15. The tendency is then for the blades to be displaced out of the plane of the loop 10. In order to avoid this, I provide a bracing means which, as shown, includes a sliding connection between the walls 37 and the blade 15. This connection may be of a universal joint type and includes a socket 38 pivotally secured to the blade 15 near the free end and a plunger 39 pivotall secured to and insulated from the walls 3 When the switch is closed, the

plunger 39 and the socket 38 form a brace, the

length of which can increase upon blade opening movement to allow for the angular movement of the blade.

Where two or more blades are actuated from the same shaft 29, thecontacts-l3' and 14in the different poles may not readily come to the same contact pressure due to variations in alinement, etc. In order to eliminate this difiiculty and yet be sure of high contact pressure, I provide a high pressure yielding means between the operating rod 30 and the switch blade. As shown, this means includes a transverse member 40 pivotally secured to the rod 30, a transverse member 41 secured to the blade 15 and between these members springs 42,- the compression of which will be according to the desired initial contact pressure.

What I claim as new and desire to secure by Letters Patent of the United States, is, 1 An electric switch including a conductor loop having two approximately parallel portions, and means for obtaining a switch contact pressure dependent on the electromaglubricant may be pronetic forces induced by a flow of eurrentin the loop when the switch is closed including a fixed contact mounted in one of said portions, and a coo crating contact mounted in said one of sai portions for movement between the fixed contact and the other conductor portion.

2. An electric switch including a fixed contact, a U-shaped conductor and means for obtaining a switch contact pressure dependent on the electromagnetic forces induced by a flow of current in said conductor when the switch is closed including in one leg of said conductor a portion thereof. angularly movable between the fixed contact and the other leg of theconductor.

3. An electric switch including a fixed contact, a U-shaped conductor and means for obtaining a switch contact pressure dependent on the electromagnetic forces induced by a flow of current in said conductor when the switch is closed including a switch blade pivotally mounted in one leg of said conductor and movable between said contact and the other leg of the conductor.

4. An electric switch includin a U-shaped conductor and means for obtaining a switch contact pressure .dependent on the electromagnetic forces induced by a flow of current in said conductor when the switch is closed including two relatively movable cooperating contactsone mounted in a leg of said conductor and the other mounted 1n said 1e for movement between said one contact an other leg of the conductor.

5. An electric switch including a U-shaped the conductor and means for obtaining a switch contact pressure dependent on the electromagnetic forces induced by a flow of current in said conductor when the switch is closed including a fixed contact mounted in a leg of said conductor, and a cooperating switch blade mounted in said leg for movement between the fixed contact and the other leg of the conductor.

6. An electric switch including a conductor loop having two portions for carryin current in opposite directions, and means or obtaining a switch contact pressure dependent on the electromagnetic forces induced by a flow of current in said loop when the switch is closed including a fixed contact mounted in one of said portions and a cooperating-contact mounted in said one portion for movement between the fixed contact and the other portion of the conductor.

7. An electric switch including a fixed contact and a U-shaped conductor including in one leg a pivoted switch blade movable between said contact and the other leg of the conductor, an operating member for actuating said blade and. a relatively high pressure resilient connection between the operating member and the blade. I

8. An electric switch including a conductor loop having two approximately parallel portions, one ofsaid portions including pivotal switch blade movable in the plane of said loop, a contact mounted in one of said loop portions adjacent the free end of said blade and on the side thereof opposite the other portion, means for actuating said blade and a fyieldin'g connection between said means and the blade. 9. An electric switch including a conductor loop having two approximately parallel portions, one of said portions including pivoted switch blade, a contact mounted in one of said loop portions adjacent the free end of the blade and on the side thereof opposite the other portion and means for preventing the displacement of said blade out of the plane of said loop.

10. An electric switch including a conductor loop having two approximately parallel portions, a fixed contact mounted in one of said portions, a cooperating contact mounted in said one of. said portions for movement between the fixed contact and the other conductor portion and means for preventing the distortion of said conductor loop under the electromagnetic forces due to current flowing in opposite directions in the conductor portions when said contacts'are engaged. 80 11. An electric switch including a conductor loop having two portions for carrying current in opposite directions, a fixed contact mounted in one of said portions, a cooperating contact mounted in said one of said portions for movement between the fixed contact and the other conductor portions, means for preventing the distortion of said conductor loop under the electromagnetic forces due to current flowing in oppm 40 site directions in the conductor portions Y when said contacts areengaged and means for reventing a displacement of said coop-= eratlng contact out of the plane of said loop. In witness whereof, I have hereunto set 4 my. hand this 26th day of June, 1929.

' JOHN D. HILLIARD.

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