US677923A - Electric switch. - Google Patents

Description

14. e. BASSETT. v ELECTRIC SWITCH.

I (Application filed Apr. 28, 1900.)

(No Model.)

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nary rheostat.

UNITED STATES,

PATENT Orrrole,

NORMAN O. BASSETT, OF BOS TON,'MASSACHUSETTS, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, OF NEW YORK.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent N 0. 677,923, dated July 9, 1901.

Application filed April 28, 1900.

To all whom it may. concern:

Be it known that I, NORMAN C. BAssET'I", a citizen of the United States, residing at Boston, county of Suffolk, State of Massachusetts, have invented certain new and useful Improvements in Electric Switches, (Case No. 1,043,) of which the following is a specification.

My present invention relates to electric switches, and has for its object to provide a simple and effective means for maintaining a switch-lever normally in a definite zero or off position and for exerting a force tending to return it to said position whenever it is moved.

My invention is particularly applicable to that type of controlling-switch for motor-'cir-' cuits in which a means is provided for lock ing the switch-lever in its operative position, the said locking means being controlled by the current flowing in the motor-circuit, so that whenever the said current fails the switch-lever will be released.

In the drawings annexed to this specification, Figure 1 shows a plan view of my invention as applied to a reversing-rheostat, and Fig. 2 is a view in side elevation.

Referring to the drawings, B indicates the box, and O the connection-board, of an ordi- On the connection-board is mounted the switch-lever L, pivoted at the point 0 and carrying the brushes at c d,which engage with the segments or contacts e f g h and the contacts '6 and e" to make the required circuitconnections. Dindicatesthebindingposts, from which circuits lead to the source of current-supply and to the motor-terminals. The switch-lever L is provided at its ends with guides G, having curved ways inclosin g straps 5, each fastened at one end of the guide to the pink and depending therefrom, the straps constituting a convenient means for manipulating the switch-lever when the rheostat itself is mounted in an inaccessible positionas, for example, near the ceiling of a room. In order to maintain the switch-lever L normally in its off position and in order to return it to such position whenever it is desired to open the motor-circuit, two springs S and S are provided. These springs are rigidly fastened at their lower ends to plugs 0 and Serial No. 14,681. (No model.)

0", pivoted on the pins Z and m, and at their other ends are fastened to nuts which engage with threaded portions on the rods 7 and r. 7

These rods are provided at their upper ends with enlarged portions and are of such a length that when the lever L is in its zero position the enlarged portions engage countersunk openings in a suitable support '11, arranged opposite the pivot of the lever, while the lower ends engage, respectively, the upper surfaces of the blocks 0 and 0". By turning the rods into the nuts at the upper ends of the springs the springs may be given any desired initial tension. As the lever L is moved in one direction or the other the tension of the spring on one side is increased, while on the other side the rod plays through the opening in the support n.

For example, when the lever L is moved in right handed rotation the tension of the spring S will be increased as the block 0 swings downward around the pivot 0, while on the other side as the block 0 swings upward around the pivot O the rod r will play through the aperture inthe support 1%. Under these conditionsthespringS,th0ugh maintained under its initial tension by the engagement of the lower end of the rod 1' with the block 0, is entirely inoperative, while the spring S is under an increased tension and tends to return the lever to its zero position. If after having been so moved the switch-lever is re leased, the spring S will throw the lever back to its zero position, and when it has reached such position the head of the rod r will again engage its countersunk aperture and the spring S will be brought into action to prevent the lever from swinging by the center. The operation when the lever is moved in the reverse direction is of course similar. The initial tension given to the springs S and S determines both the force with which the lever will be thrown back to its zero position and the force opposing the movement of the lever past its zero position when it is thrown back. By proper adjustment of the tension of the springs, therefore, the lever may be given any desired impulse within the capacity of the springs and may be prevented from vibrating when it comes to its zero position.

It is evident that it is not necessary that the upper ends of the springs S and S shall be supported from a single member. Instead of supporting these springs, therefore, from the support at, a separate support may be provided, if desired, for each. In order that the switch-lever may be maintained inits full-on position when turned either to the right or to the left, an electromagnet M is provided hav- 1o ing polar extensions on each side at the top and bottom, the support at constituting one of the poles of the magnet and the part 19 the other. The lever L is provided at each end on its upper side with armatures A and A,

adapted to engage the polar projections of the said magnet. This magnet is supplied with current in series with the motor-circuit eontrolledby the said switch, as is customary in motor-controlling switches, so that whenever 20 the current-supply fails for any reason the switch-lever will be released and returned to its zero position.

, The operation of my device. is as. follows:

When it is desired to start the motor in one direction, the lever L is moved by means of one of the straps s-as, for example, the one on the left-until the brushes a, and Z). come into contact with their corresponding segmentsf and h and brushes 0 and cl comeinto contact with the segment 9 and withone of the contacts 2. As the switch-lever is still farther moved the brush cl engages the successive contacts 2 gradually cutting out the resistance of the rheostat in. a manner well understood, until, finally, when the switch-lever has reached its full-on position the ara mature A comesinto contact with the poles of. the electromagnet M, and the switch-lever is held thereby so long as the current flows 40 in the motor-circuit. \Vhenever the current fails in the motor-circuit, the arm atn re A will be released and the switch-lever returned to its zero position in the manner alreadydescribed, and also whenever it is-necessary to stop themotor the armature A maybe withdrawn from engagement with the polar projections of the magnet M by means of the strap 3 on the right. If it is desired to cause rthe motor to rotate in the opposite direction,

the lever L will be operated by the straps on .the right to bring the brushes a and 7) into plied to a reversing-rheostat, it is evident that itis not limited thereto,but maybe used in con nection with any switch member whenever it is desired to maintain such member in a definite off position unless it is not positively held in an operative position, and although I have shown an electromagnetic means for n1aintaining the switch-leverin either of its oper- .ative.positions it is evidentthat I am not limited thereto, but may use any suitable looking means for maintainingthe leverwin such positions.

What I claim as new, and desire to secure by Letters Patent of the United States, is-- 1. Incombination, a pivoted-switch memher and a plurality of spring devices for re turningsaid member to its off position from either direction, each of said devices being so .mounted that. it is inoperative in.one.direc tion of movement of the switch member, and each comprising two members normally maintained in engagement by a spring connection.

2. In combination, a pivoted switch-lever, blocks rotatably mounted on either side of the pivotfot' said lever, a plurality of fixed sup ports, rods having at their upper endsenlarged portions normally engaging said sup-' ports and having their lower ends normally in engagement withsaid blocl-:s,and springs,- eaeh fastenedat one end to one of saidblocks and at the other end to a point on one ofsaid rods.

In witness whereof I have hereunto set my hand this 25th day or" April, 1900.

NORMAN BASSET' \Vitnesses:

DUGALD MeKILLor, CHAS. B. Bnrnnnn.

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