US2489750A - Electric switch - Google Patents

Description

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Patented Nov. 29, 1949 ELECTRIC SWITCH John R. Caldwell, Hampton, Olan Richardson, Atlanta, and Thomas E. Curtis, Hampton, 6a., assignors to Southern States Equipment Corporation, a corporation of Georgia Application January 10, 1947, Serial No. 721,184

3 Claims.

This invention relates to electric switches in which a hingedly mounted switch arm is moved into' and out of engagement with a contact spaced away from the hinge mounting, and in which the pressure between the switch arm and the contact is increased after the-switch arm has completed its arcuate motion in closing. More particularly it relates to the type of switch in which this increased pressure is produced by a partial rotation of the switch arm about its longitudinal axis.

Referring to the drawings, Fig. 1 shows in reduced scale a single pole of one type of switch embodying this invention; Fig. 2 is an enlarged side view of the hinge portions of the switch; Fig. 3 is a top view of the parts shown in Fig. 2; Fig. 4 is a sectional view along the plane 4-4 when the switch arm is midway in iii rotative travel; Fig. 5 is a longitudinal view along the section 5-5; Fig. 6 is an end view of the switch arm and the contact: Fig. 1 is a diagram explaining one part of the operating motions of the switch; Fig. 8 is a top view of a modified arrangement of the operating member; and Fig. 9 shows a detail.

The base I supports two stationary insulators 2, 3 and one rotative insulator 4 which is controlled by crank 5. The crank l is integral with the rotative insulator unit 4. The hinge base I is secured to insulator 3 and it also serves as e a steady bearing for the top of insulator unit 4.

Line 8 is connected to hinge base I, and line 8' is electrically connected to contact l3. Switcharm structure 9 is hinged on hinge pivot l0 and it includes the switch arm II which is rotative about its own longitudinal axis. Switch arm II has a flattened end l2 which engages with contact l3. Rocker I4 is mounted on hinge base 1 by rocker pivot II which is parallel with hinge pivot I0, connecting rod I6 is held by a universal joint to crank 6, and, a second universal joint and swing pivot I! hold connecting rod IE to rocker I4. Swing pivot II also carries two curved links l8, l9 which are connected by diagonal pivot 20 to terminal bearing member 2| which is integral with and a part of rotative switch arm II. The switch-arm structure 9 also includes the hinge member 22 which is mounted on the hinge base I by hinge pivots l0, l0, and which provides the trunnion in which terminal bearing member 2| rotates.

Fig. '7 is a diagram showing how switch arm ll is-rotated by motion of rocker l4 and links I8, I9. When the switch is fully closed swing pivot I! is at position indicated by IIa and the link I! is indicated by Na, with the near end of diagonal pivot 20 being at a. The location of rocker pivot I5 is shown at lia. Link i8 occupies the position indicated by l8a, with the far end of pivot 20 being at location c. As rocker i4 is moved so that swing pivot I1 is moved to position llb, the link l8 takes position l8b and link l9 takes position lab. In other words the near end of pivot 20 is raised to b and the far end of pivot 20 is lowered to d. This places link IS in tension and link It in compression and as they are on opposite sides of switch arm I I they rotate switch arm ll without otherwise changing its location. Fig. 8 is a plan view showing how the two links l8, is can be replaced by a single bifurcated member 23 which is mounted on diagonal pivot 20 and on swing pivot I! without altering the locations of saidpivots. In this case swing pivot ll passes through the single eye 24 which is integral with 23, and which fits within the clevis 25, which is part of the universal joint connection to connecting rod It. In this case, the single 23, 24, 22 is rotatable about the straight diagonal pivot 20, the eye 24 tending to move at right angles to axis of pivot 20. However, the rocker l4 forces swing pivot ll to travel at right angles to axis of pivot I5. The resultant is the same as with two separate links, namely to raise one end of pivot 20 and lower the other end, thereby causing rotation of switch arm II. There are slight discrepancies in the travel of the various members, and when two links such as l8, it are used, proper clearances are allowed at each end of each link to prevent binding. When a single bifurcated link is used such as 23, 24, 23 all the clearance for these slight discrepancies is provided between eye 24, clevis 25 and swing pivot l'l. As shown in Fig. 9, the link 23, 24, 23 may be replaced by the swivelled members 23', 24', 24" the swivelled eye 24 replacing the rigid eye 24. In such arrangements,

no extra clearance is needed between eye 24' and clevis 25.

Operation is as follows: Assuming the switch to be fully closed, the fiat end l2 of arm H is horizontal and is in heavy pressure engagement with contact members l3, l3; Hinge members are as shown in Fig. 2. When crank 5 is turned, connecting rod l6 moves rocker l4 counter-clockwise moving swing pivot 11 from position lie to "D. This places link I! under tensionand link It under compression. This partially rotates switch arm ll so that end I2 is released from heavy pressure against contact l3, l3. Further motion of crank it moves pivot l'l so that the 3 plane which includes the axes of pivots l1 and i5 is past the locations 0 and d. Further counterclockwise motion of rocker i4 changes the stress on link It from compression to tension so that links l8 and I9 are both in tension and this lifts the diagonal pivot 20 and so raises switch arm ll through its operating plane, which is normal to the axis of pivots l0, Hi, until the switch arm ultimately reaches its fully open vertical position. Since the axes of pivots l0, l8 and ii are parallel, the motion of swing pivot I! is likewise parallel with the operating plane.

through which switch arm ll swings.

The reverse motions close the switch and rotate arm ll so that end I! is again horizontal as shown in Fig. 6 and the switch is fully closed.

If it should be desired, diagonal pivot 20 could be replaced by two separate pivots which need nothave the same axes. Instead of pivot l1 serving as the connection with connecting rod IS, a second pivot could be provided adjacent to pivot I I. And various other changes might be made by one familiar with the art without departing from the spirit and purpose of this invention.

We claim:

1. In an electric switch, an insulated contact, and spaced away from it an insulated hinge base carrying a hinge pivot, a switch arm mounted on said hinge pivot to swing through its operating plane from its open position to its closed switch location and into engagement with saidcontact and also rotatable about its longitudinal axis when at its closed location, a rocker pivot mounted in a fixed position on said hinge base spaced from and parallel with said hinge pivot. a rocker mounted on said rocker pivot, a swing pivot in the swing end of said rocker and movable only in a fixed are parallel with said operating plane, and linkage directly connecting the swing pivot with the rotatable switch arm to rotate the switch arm when at its closed location, together with means to move the rocker in one continuous motion and so operate the switch from fully closed to fully open position.

2. In an electric switch an insulated contact and spaced away from it an insulated hinge base carrying a hinge pivot, a switch arm mounted on said hinge pivot to swing in its operating plane into and out of engagement with said contact and also rotatable about its own longitudinal axis when at its closed switch location, a rocker pivot also mounted on said hinge base and a rocker mounted on said rocker pivot, with its swing end movable only in a fixed are about the rocker pivot and parallel with said operating plane, two links pivotally connected to the swing end of the rocker and with their other ends pivotally connected with the rotatable switch arm at substantially diflerent distances from the hinge pivot and operable by motion of the rocker to rotate the switch arm about its longitudinal axis when the switch arm is at its closed location.

3. In an electric switch, an insulated contact and in spaced relation to it an insulated hinge base carrying a hinge pivot, a switch arm mounted on said hinge pivot to swing in its operating plane from its open position to its closed switch location and into engagement with said contact and also rotatable about its own longitudinal axis to vary its engagement pressure with said contact. a swing pivot movably supported upon said hinge base and movable only in a fixed are parallel with said operating plane, two links pivotally connected with said swing pivot and with their other ends pivotally connected to opposite sides of said switch arm at susbtantially diflerent distances from said hinge pivot and operable to rotate the switch arm when at its closed location, together with operating members to move the swing pivot and thereby to operate the switch.

JOHN R. CALDWELL. OLAN RICHARDSON. THOMAS E. CURTIS.

REFERENCES CITED The following references are of record in the tile 01' this patent:

UNITED STATES PATENTS Number Name Date 1,560,998 Koppitz Nov. 10, 1925 2,276,257 Caldwell Mar. 10, 1942 2,303,119 Froland Nov. 24, 1942 2,328,171 Schwager et a1 Aug. 31, 1943

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