US1308043A - Controller - Google Patents

Description

I. R. COOK.

CONTROLLER.

APPLICATION FILED JULY 6| I9 I5.

' Patented July 1, 1919.

2 SHEETSSHEET l.

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.wr I I WITNESSES I INVENTOR 0% Jae/5600K ATTCRNEY J. R. COOK.

CONTROLLER.

APPLICATION FILED JULY 6,1915

1,308,043. Patented July 1, 1919 2 SHEETS-SHEET 2.

WITNESSES INVENTOR UNITED STATES PATENT OFFICE.

JOEL B. COOK, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CONTROLLER.

Specification of Letters Patent.

Patented July 1, 1919.

Application filed July 6, 1915. Serial No. 38,158.

To all whom it may concern:

Be it known that I, JOEL R. @0011, a citizen of the United States, and a resident of \Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Controllers, of which the following is a specification.

My invention relates to controllers and particularly to such devices as are adapted for use in connection with electric motors of small horsepower.

My invention has for its object to provide a simple and compact arrangement for efficiently controlling the operation of electric motors.

Controllers constructed in accordance with I my invention are particularly adapted for use in connection with electric motors that are employed to drive sewing machines and similar mechanisms which are operated more or less intermittently. I provide a'pair of resistors of the well known form in which the resistance element is wound upon a cylinder of insulating material. These resistors are connected in series with the motor to be controlled. The resistors are gradually shunted by means of a curved resilient conductor the curvature of which is gradually reduced to effect contact engagement with the resistors and, at the same time, the conductor moved longitudinally to effect a sliding or wiping engagement therewith.

The details of my invention will be described in connection with the accompany ing drawings in which Figure 1 is a "view, partially in plan and partially in section, of a controller constructed in accordance with my invention, the cover being removed. Fig. 2 is a view, in longitudinal section, of the mechanism of Fig. 1, the cover being in place. Fig. 3 isa view, in transverse sec tion, of the mechanism of Fig. 2. Figs. 4 and 5 are views in elevation and in plan, respectively, of a resilient contact member. Fig. 6 is a diagrammatic view of circuits and apparatus embodying my invention. Fig. 7 is a view, in section, illustrating certain details of the pivotal support for the lever.

Referring particularly to Figs. 1, 2 and 3, a controller 1 comprises a casing 2 of substantially rectangular shape. Two resistor units 3 are rigidly secured to the bot tom of the casing by means of a member 4.

Each of the resistor units 3 consists of a resistance element 5', such as, for example, nichrome wire, that is wound upon a cylinder of insulating material and the respective termlnals of which are connected to contact members 6 and 7.

A lever 8, which is arranged for vertical movement between the resistors 3, is pivotall y supported, at one end, by means of two pro ect1ng plates 9 having vertically extending slots 10 of approximately triangular shape. A pin 1].,Wl1l0l1 extends transversely through the end of the lever 8, is provided with reduced end portions upon each of which is mounted'a grooved wheel 12. The slots 10 are of such size that the pin 11 and the grooved wheels 12 may be passed through them for convenience in assembling.

A spring 13, which is connected, at one end, to a stationary part, and, at the other end, to the lever 8, exerts force upon the latter to retain the wheels 12 in engagement with the vertical edges of the slots 10 throughout the movements of the lever 8. A

spring 14; also tends to retain the pivotal cover 18 and its connected parts in their respective illustrated positions, with the plate 16 and the contact member 17 out of engagement with the contact members 6 and 7 and the resistance element 5.

As shown in Fig. 6, line conductors 20 and 21 supply current to an electric motor 22 which may be operatively connected to any suitable mechanism to be driven. The motor circuit, which is normally open at the re sistors 3, is controlled by the contact member 17 and the conducting plate 16.

To start the motor, the operator presses the cover member 18jdownwardly and the- .lever 8 is actuated about its point of pivotal support to effect the engagement of projecting portions 23 of the contact member 17 with the contact members 6 that are connected to the terminals of the corresponding resistors. The motor circuit is then completed through the resistors 3 in series. Further movement of the lever 8 causes its piv otally supported end to be actuated upwardl about the projections 23 as a fulcrum.

At the same time, the spring 13 causes the lever S to move longitudinally, and the projections 23 have, therefore, a sliding engagement with the contact members 6. This operation causes the surfaces of the coacting contact members to be kept free from the products of corrosion caused by the arcs incident to the closing and opening of the motor circuit. Further movement of the lever S in a downward direction decreases the curvature of the contact plate 16 to ef fect contact engagement thereof with the upper surfaces of the resistors 3 to gradually shunt the coils of the resistance element The curvature of the contact member 17 is correspondingly decreased to permit contact engagement thereof with the contact plate 16.

The longitudinal movement of the lever 8 and the contact members carried by it continues substantially throughout the operation of the controller. hen the lever 8 is at the end of its path of movement, projections 2% of the contact member 17 engage contact members 7. to completely shunt the resistors 3 and projections 23 are disengaged from the contact members 6. The motor, which has been gradually accelerated by the removal of resistance from itscircuitJthen operates at its normal speed.

' To stop the motor, the operator decreases the pressure applied to the cover 18 and the spring 19 returns the latter and the lever S to their respective inoperative positions. The projections 12% are first disengaged from the contact members 7 and the contact plate 16 is gradually permitted to resume its curved shape and thereby gradually insert resistance in the motor circuit. The circuit is broken by the separation of the projections from the contact members 6. The return of the lever S to its illustrated Josition insures that the wiping contact of the coacting members occurs during the return of the several parts to their respective inoperative positions.

It will be noted that I provide a simple and etficient means for controlling the circuit of an electric motor whereby the motor is gradually accelerated toits normal speed and is brought to rest by the gradual increase of resistance in its circuit. This result is accomplished by means of a controlling device having the novel arrangement of partsand operating characteristics above set forth.

I claim as my invention: 1. In a controller, the combination with a wound resistor, and a plate member for gradually shunting turns of said resistor, of means for effecting simultaneous lateral and longitudinal movements of said member.

2. In a controller, the combination with a wound resistor and a resilient plate member for gradually shunting turns of said resistor, of means for effecting simultaneous lateral and longitudinal movements of said resilient member.

3. In a controller, the combination with a resistor, and a curved flexible plate of conducting material for coacting therewith, of means for causing said plate to conform to the surface of said resistor and, at the same time, to have a sliding engagement therewith.

4:. In a controller, the combination with a resistor, and a curved resilient member for coacting therewith, of means for causing said member to gradually engage said resistor, and, at the same time, to have a wiping contact therewith, said means compris ing a pivotally mounted lever.

5. In a controller, the combination with a resistor, and a curved resilient member for coacting therewith, of means for causing said member to gradually engage said resistor and, at the same time, to have a wiping contact therewith, said means comprising a pivotally mounted lever for carrying said member.

6. Ina. controller, the combination with a resistor, and a member for coacting therewith mounted on a lever having a floating pivotal support, and a spring tending to actuate said lever longitudinally.

7. In a controller, the combination with a resistor, and a. member for coacting therewith mounted on av lever having a floating pivotal support, means tending to actuate said lever longitudinally, and means for yieldingly retaining said lever and said member in an inoperative position.

8. In a controller, the combination with a spirally-wound resistor and a resilient member for coacting therewith, of means for simultaneously actuating said member longitudinally and causing it to shunt a varying number of turns of said resistor, said means comprising a pivotally-mounted lever and av spring for normally retaining said lever and said member in an inoperative position.

9. In a controller, the combination of a re sistor, a resilient conducting member for coacting therewith, and a pivotally and slidably mounted lever connected to said member.

10. In a controller. the combination with a resistor, and a flexible conducting strip, of means for simultaneously actuating said strip longitudinally and causing it to progressively shunt said resistor. said means comprising a loosely pivoted lever carrying the strip, and means for actuating the lever and connected parts to cause sliding engagement of the strip with the resistor.

11. In a controller, the combination with a resistor. and a curved flexible conducting member of substantially the same length as said resistor and disposed adjacent thereto of means for exerting a lateral pressure on said flexible member to cause it to gradually shunt said resistor.

In testimony whereof, I have hereunto subscribed my name this 29th day of June 1915.

JOEL R. COOK.

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