US1780612A - Motor-controlling device - Google Patents

Description

Nov. 4, 1930. c. J. ANDERSON ,5

MOTOR CONTROLLING DEVICE Filed June 29, 1928 2 Sheets-Sheet l NOV. 4, 1930. Q ANDERSON 1,780,612

MOTOR CONTROLLING DEVICE Filed June 29, 1928 2 Sheets-Sheet 2 far/ of 4770 823907?- Patented Nov. 4, 1930 PATENT @FFEE CARL J". ANDERSON, OF CHICAGO, ILLINOIS MOTOR-CONTROLLING DEVICE Application filed June 29, 1928.

My invention relates to devices for controlling the operations of reversible motors, and has for its object improvements in such devices.

In the accompanying drawings Fig. 1 is a front elevation of a controlling device illustrating my invention;

Figs. 2 to 5, inclusive, are sections on correspondingly marked lines of Fig. 1; and

Fig. 6 is a diagram of the circuits involved.

Mounted upon a slate 9 is a solenoid 10 having an armature 11, said solenoid being preferably supported in a vertical position so that the armature will fall by gravity to its 5 lower position as shown in Figs. 1, 2 and 3.

Supported near the lower part of the slate 9 are standards 12 and 13 which carry a horizontal shaft 14, and secured on this shaft is a four-toothed ratchet wheel 15. Pivoted upon the shaft 14, and adjacent to the ratchet wheel 15, is an arm 16 which carries a pawl 17 adapted to engage the teeth of the ratchet wheel. On the arm 16 is a lug 18, and between this lug and the pawl 17 is a spring 19 which serves to press the pawl into contact with the ratchet wheel.

Pivoted in the lower hollow end of the armature 11 is a connecting rod '20, the lower end of which rod is connected to a pin 21 carried in the end of the arm 16, said pin 21 serving also as a pivoting pin for the pawl 17. The construction is such that when the armature 11 is attracted by energizing the solenoid 10, the arm 16 is moved to cause the pawl 17 to advance the ratchet wheel one step, and'consequently to advance the shaft 14 and parts carried thereby. When the solenoid is de-energized, the armature falls back to its lower position and carries the pawl back into a position adapted to engage the next tooth of the ratchet wheel when the solenoid is again energized. This lower position of the armature is determined by a pro jection 22 on the standard 13, which projection serves as a stop as shown in Figs. 2 and 3.

Secured to the slate 9 are three brackets 23, 24 and 25, and pivoted to these brackets are contact levers A, B and C. Under the upper ends of these levers are contact blocks, one of which is shown at in Fig. 3. Under the Serial N0. 289,232.

lower ends of the levers, and near the brackets to which the levers are centrally pivoted, are springs 26, one of which is shown in Fig.

3. These springs act to normally press the upper ends of the levers into contact with their respective contact blocks.

The lower ends of the levers A, B and O are provided with rollers 27 which are adjacent to cams 28, 29 and 30 secured upon the the shaft- 14. These rollers are made of insulating material to prevent electrical connection being made from one lever to another by way of the shaft 14.

The cams 28, 29 and 30 act to depress the lower ends of the contact leversA, B and C against the action of their springs 26 so as to lift the upper ends from their respective contact blocks or points. Later the cams release said levers so that the springs 26 may operate to close electrical connections as will be explained hereinafter.

Figs. 3, 4 and 5 represent the cams 28, 29 and 30 in their normal positions, which are the positions in which all contact levers are lifted from their contact blocks. Cam 28 has on it two projections, between which projections are two depressions or parts cut away. As a consequence, a complete revolution of the cam will twice lift the lever A from its contact block 40 and twice permit the spring 26 to complete an electrical connection.

The cam 29 (Fig. 4) has a depression at 31, and consequently when the cam makes one complete revolution the lever B will be permitted to close an electric circuit only once in such revolution. Similarly, the cam 30 has only one depression shown at 32, and consequently the lever O can close an electric circuit only once in a revolution of cam 30.

The shaft 14 and the cams secured thereto move in a clockwise direction as shown by the arrows in Figs. 4 and 5. By inspection it will be seen that the cam 29 must move threequarters of a revolution before the lever B can move under the action of its spring 26 95 from the full line to the dotted line position.

By similar inspection it will be seen that the cam 30 will permit lever C to move from full line to dotted line position as a result of only one-quarter of a revolution of said cam. 1

And by reference to Fig. 3 it will be seen that cam 28 permits lever A to close electrical connections at one-quarter revolution and again at three-quarters revolution.

It is to be observed that cam 29 permits an electrical connection to be made only when the roller 27 of lever B comes to the depression or recess 31. At all others parts of the cam surface the cam is idle, as far as any efiect upon the making of an electrical connection is concerned. Similarly, cam 30 has a lever operating recessonly at the point- 32, all other parts of the cam surface being non-effective as faras contact making is concerned. 7

Normally, cams of this kind would be round between the points at the beginnings and ends of the operative recesses, that is, those parts of the cams which did not affect the contact making operations would be at uniform radii from the center of the shaft for'the-sake of economy of power and the avoidance of wear. It is to be observed, however, that these cams have flat surfaces. That is, each cam is in the form of a square, with a recess on one side, and the extreme corners cut off. r

Asbefore described, the shaft 14 has on it a ratchet wheel having four teeth, and the shaft is advanced by a solenoid having considerable power. When the solenoid is energized, the armature 11 is attracted rapidly, and has a length of movement determined by it coming into contact with an internal stop as is customary with devices of this kind.

The shaft 14 and parts connected'securely thereto are comparatively heavy, and the consequence is that they do not stop suddenly when the armature stops, but have a tendency to-over-run by mere momentum.

The cams 29 and 30 have fiat faces between the cut off corners, and the centers of these flat faces correspond with the teeth on the ratchet wheel 15. That is, when the ratchet wheel is in the position shown in Fig. 2, one orboth of the cams 29 and 30 have the centers of fiat faces in contact with rollers 27. To move the shaft 14 either way from the position shown in Figs. 4 and 5 would be to de press levers B and G against the force of their springs 26. As a consequence of the, structure set forth, the springs 26, the levers B and G, and the flat faces of the cams 29 and 30 act to prevent the ratchet wheel and other rotary parts over running at the termination of a stroke by the armature 11.

In the diagram of Fig. 6, M is a reversible motor, P is a push button, and L is a limit switch. The motor M is used to move anything as a door, a gate, or an elevator, first in one direction and later in the other. The limit switch L is simply an electrical connection whichis closed mechanically by the moved object as it reaches the end of its movement in either direction. Its purpose is to stop the motor by bringing about an operation which will break the motor circuit.

The diagram shows the parts in their normal or idle position, except that in such posithe motor to open a door or move some other object, as indicated at D in Fig. 6, he presses the button P. Thereupon a current from the source 7 flows as follows :source3334. solenoid 10'-35P36source.

This energizes-the solenoid and advances the shaft 14 and cams thereon one step. By this advance, cams 28 and 30 permit levers A and C to close connections with their contacts 40 and 37. Thereupon a current flows :source33C37r+38' M39sour ce;

V This starts the motor inthe proper direction to open the door. The first movement of the door opens the switch L, but as this switch is not in the motor circuit, such opening produces no result beyond breaking the circuit for the solenoid. When this circuit is broken, the armature fallsback to bring pawll'? into position to engage the next tooth of the ratchet wheel, but otherwise accomplishes nothing.

, Asthe door I) or other moved object reaches the end of its destined movement, it-closes the switch L, whereupon a new circuit is completed' and a current flows as follows source 33-34solenoid3540 lever A414236source. Thisadvances the cams 28, 29 and 30 another quarter of a revolution, or a total of a half revolution beyond the starting positions shown'in Figs. 3, 4 and 5. In these positions the levers A, B and C will all be open as shown in full lines in said figures.

What has just been given represents opening a door or moving any other object from one position of rest to another position of rest. If the operator then or later wishes to closethe door, he presses the button P as before, and another impulse flows thru the solenoid to advance the shaft 14 and cams thereon another quarter revolution. This leaves levers A and B closed, and lever C open. Under these conditions a current fiows:source33B43,--44M 39source.

This starts the motor inthe reverse direc-, tion. The first movement of the door operates to open the switch L, and the final part of the door movement closes this switch as described before. The consequence of this procedure is to send another impulse thru the solenoid to advance the cams so as to leave all levers open at their contact points. The movement last indicated completes a full revolution of the shaft 14 and leaves the 1,7so,e 12

parts of the apparatus in the position from which they started.

It is to be observed that the contacts closed by the lever A and the limit switch L are parallel with the contacts closed by the button P. As a consequence, the solenoid may be operated either by the push button or by the simultaneous closure of A and L. This makes it possible to start the motor in each of its directions by a single push button instead of by a complication of two or more buttons in which the operator is obliged to select the desired button from a plurality of buttons. From the description it will be evident that the functions of lever A are to prepare the circuit of the magnet for ultimate closure by the limit switch, and to break the circuit for the magnet so that the limit switch may remain closed when all parts are in idle position. Otherwise, the lever A serves no purpose.

In the upper part of Fig. 1 is shown a knife switch for connecting the circuits shown in Fig. 6 to a source of electrical energy, but as such switch is well known, it is not herein described.

What I claim is:

1. In a device of the class described, contact closers, springs serving to move said contact closers to contact closing positions, a shaft provided with electrical connections for advancing it step by step, and cams on said shaft and serving to open said contact closers by depressing the springs thereof, said cams having their surfaces so constructed that the tension of said springs operates thru the cams and the shaft to prevent the parts over-running at the termination of each step of the step by step movement.

2. In a device of the class described, a shaft provided with a ratchet wheel by which it is advanced step by step, cams of polygonal form, each cam having as many sides as there are teeth in the ratchet wheel, and springs operating thru the sides of the cams to restrain the parts from over-running at the end of each step of the step by step operation.

CARL J. ANDERSON.

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