US1194125A - Sylvania - Google Patents

Description

H. F. BETHUNE.

RHEOSTAT.

APPLICATION FILED MAR. 1, 1911.

Patented Aug. 8, 1916.

2 SHEETS-SHEET I.

i nhn WiTNESSES'. 65.1

INVE TOR :ATTORNEY H. F. BETHUNE.

RHEOSTAT.

APPLICATION FILED MAR-1.1911.

2 SHEETS- SHEET 2.

Patented Aug. 8, 1916.

INVENTOR ATTURNEY J WITNESSES:

UNITED s'rarns grnntr OFFICE.

HARRY F. BETHU'NE, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYL VANIA.

RHEOSTAT.

To all whom at may concern Be it known that I, HARRY F. BETHUNE, 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 Rheostats, of which the following is a specification.

My invention relates to electrically operated remotecontrol rheostats and it has special reference to such devices as are adapted 'to be operated by electro-magnets.

The object of my invention is to provide a comparatively inexpensive device, of the above indicated class, which shall be exceptionally effective and reliable in operation.

Heretofore, it has been common to employ remote-control rheostats for regulating the speed of motor-driven machinery or the voltage of generating units. In general, however, such devices have been motordriven and have, therefore, involved considerable unnecessary expense. Electromagnetically operated field rheostats have also been employed to some extent, but have not proved entirely satisfactory, from an operating standpoint, on account of their non-uniform intermittent action and non-adjustable speed of operation.

According to my invention, I provide a rheostat that may be operated at a predetermined uniform speed, in either direction, by independent electro-m'agnets, and embodies means for regulating the speed of operation, means for automatically arresting the operation at the limits of travel in either direction, and means for effecting a positiveand uniform operation in either direction, of rotation.

In the accompanying drawings, Figure 1 is a back view of a rheostat constructed in accordance with my invention, a portion of' Specification of Letters Patent.

Patented Aug. 8, 1916.

Application filed March 1, 1911. Serial No. 611,730.

panel 8'and supports the various parts of the operating mechanism, while the resistor 9 may be arranged and mounted 'on the back of the panel 8 in the usual manner. The resistor 9 may be constructed in any well known manner and is sub-divided into a plurality of units 21, each of which is connected "between adacent contact buttons 10 which are disposed upon the face of the insulating panel 8 in the form of a circle. The rotatable arm 11 is rigidly fastened to the ratchet wheel 12, which is mounted upon a shaft 22 having an insulating handle 23 secured at its outer end. The proportions of theratchet wheel and the number of notches thereon are so chosen that the contact arm 11 is advanced from center to center of the contact buttons as the device is operated.

The electro- magnets 13 and 14, which are suitably mounted upon the supporting frame 7, are of like construction and each comprises ,a stationary core 24, a movable core 25, and a magnet winding 26. The operating levers 15 and 16, which are also of like construction, are pivotally mounted, at their outer ends, upon shafts 27 and 28, respectively, and are pivotally connected, at their inner ends, to the dash pots 18 and 17, re spectively. The levers 15 and 16 are also pivotally connected to the movable core members of the electroma'gnets 13 and 14 recess near the middle of each operating lever, a spring 34 being suitable secured to the operating lever to cooperate with the lo er end of said dog in order to maintain it in its operating position and to permit it to free itself from the ratchet wheel on the back stroke of the operating lever. A projection 35 of the operating lever 15 is disposed upon the rear side of the ratchet wheel 12 and is adapted to be engaged, under predetermined conditions, by a stop or pin 40, with which the'ratchet wheel is provided, for the purpose of limiting the operation in a clockwise direction. Similarly, a projection 35 of the operating lever 16 is disposed upon the front side of the ratchet wheel 12 and cotiperates with a stop 41 for a similar purpose. A coil spring 36 is adjustably secured between each operating lever, and a boss 37 on the supporting frame 7.

The dash pots .17 and 18, which are pivotally suspended from pins 42 and 43, are of well known construction and perform well known functions.

The make and break devices 19 and 20 are of like construction and each comprises a lever member 50 which is pivotally mounted upon a pin 51, near its outer end and is provided, at its inner end, with a projecting portion 52 having buffers 53, of relatively soft material, on its respective sides. A coil spring 54 is adjustably secured between the boss 37 and an extension member 55 of the lever 50 and a projection 56 of said lever limits its upward movement. Near the inner end of each lever 50, a supporting member 57 is pivotally'suspended from a pin 58 and said member is provided with a contact terminal 59 at each end, said terminals being electrically connected together and adapted to engage cotjperating stationary contact terminals' 60, under predetermined conditions. The stationary terminals 60 are secured to a supporting member 61 which is suitably mounted upon the supporting frame 7. A body of magnetizable material 65 is provided upon the lever member 50 to serve as an armature for an electro-magnet. 66 which comprises a magnetizable core member 67, having upwardly projecting end portions 68 and a magnet winding 69. The electromagnet 66 is adapted to restrain the lever member 50 until it is released by reason of engagement with one of the levers15 and 16.

Assuming the various parts of the device to occupy the positions shown in the drawings, it will be observed that all of the resistor 9 is out out of the field circuit of anotor 3"and the contact arm 11 is in its extreme counter-clockwise position. The motor 3 ,is adjusted, therefore, for slow speed operation. If it should be desired to increase the speed of motor 3, a double-throw switch 70is closed upon a stationar tact terminal 71, thereby completing a circuit from the line conductor, through conductor 72, switch member 70, stationary contact terminal 71, conductor 7 3, stationary contact terminals 60, movable contact terminals 59, conductor 74, magnet winding 69, conductor 75, the winding 26 of the magnet 13 and conductor 76 to the line conductor 2. Upon the completion of the circuit just recitedfthe electro-magnet 66 of the make and break device 20 and the operating electromagnet 13 become energized and the operating lever 15 is raised, thereby causing the dog 32 to engage oneof the notches of the ratchet Wheel 12 and to actuate it in a clockwise direction.

Inasmuch as the tension of coil spring 54 is less than the force exerted by the electromagnet 66, the coiiperating contact terminals 59 and 60 are maintained in engagement as long as electro-magnet 66 is energized. As the operating lever 15 reaches the top of its stroke, however, the adjustable setscrew 30 engages the bottom cushion 53 of .the projecting portions of the lever 50 action of the dash pot 18 which introduces a predetermined time element. It will be understood that, by varying the tension of the spring 36, the speed of operation may also be varied, as desired. As the lever member 15 falls to its lowest position, the lower edge of the web 31 engages the upper cushion 53 of the projecting portion 52 of the lever member 50 and thus causes engagement of the stationary and movable contact terminals 59 and 60. It is evident, therefore, that the energizing circuit is again established and that the cycle of operation just recited will be continued intermittently until the switch member 70 is disengaged from its contact terminal 71, as will be readily understood.

Those skilled in the art will readily understand that, as the ratchet wheel 12 and contact arm 11 are rotated, step-by-step, in a clockwise direction, the resistor 9 is cut into the field circuit of the motor 3 and, hence, its speed is increased, according to Well known principles. Assuming the contact arm 11 to occupy some intermediate position with respect to the resistor 9, it is evident that a decrease in motor speed may be effected, in a similar manner, by closing switclnmember 70 upon a contact terminal 80, whereby a circuit through the make and break device 19 and the operating electromagnet 14 is established.

On account of the simplicity of the circuit arrangements and the similarity to those hereinbefore described, it is believed that those skilled in the art will experience no difiiculty in understanding the circuit connections and the mode of operation in a counter-clockwise direction.

Assuming that the switch member 70 closed upon the contact terminal 80, thereby causing movement of the contact arm in a counterclockwise direction, it is evident that intermittent rotation continues automatically until the contact arm 11 has reached its limit of travel in a counter-clockwise direction, in which position the stop ll is advanced to make contact with the projecting member of the operating lever 16 and thus prevents the closure of the cooperating contact terminals 59 and 60 of the make and break'device 19. Hence, the operation of the rheostat is automatically discontinued and the energizing circuits are interrupted. In a similar manner, the operation in a reverse direction is automatically arrested at the limit of travel.

It is evident that a definite and positive operation of the apparatus is effected by reason of the direct means of actuating the make and break devices 19 and 20 and the cooperative action of the electro-magnets 66, as hereinbefore described, and hence a uniform speed of operation is secured.

My invention is not restricted to use with rheostats alone, as various classes dfiapparatus, in which arot'ative movement is required, may also be operated by similar means and in a similar manner. Neither is the device in question limited to'operation in two directions, as certain types of apparatus to which my invention pertains, are essentially adapted for uni-directional rotation.

While I have illustrated and described a circuit controlling device of a specific structure and circuit arrangements, it is evident that many modifications may be effected in the size, arrangement and location of parts and circuit connections, without exceeding the scope and spirit of my invention. and I desire that only such limitations shall be .imposedas are indicated in the appended claims.

.I claim as my invention:

1. The combination with a rheostat comprising cooperating stationary and movable contact members and a resistor connected to .said stationary contact members, of a ratchet wheel, rigidly associated with said movable member, lndependent operating mechanisms for intermittently actuating said ratchet wheel, each comprising an electro-magnet, a

pawl, a time element device, a positively actuated make and break device and an electromagnet connected in series circuit with said make and break devicefor effecting the operation thereof.

2. The combination with a rheostat comprising cooperating stationary and movable contact members, and a resistor connected to said stationary contact members, of a ratchet wheel rigidly associated with said movable member, independent and duplicate means for actuating said ratchet wheel in opposite directions, each comprising an electro-magnet, a pi'votally mounted pawl member connected to said electro-magnet, a time element device associated with said pawl member, means positively actuated by said pawl member for intermittently app ying elec trical energy to said electro-magnet and means in circuit with said electro-magnet for opposing said last means.

3. In a rheostat, the combination with a plurality of resistance elements, a set of stationary contact terminals disposed in a circle and connectedvthereto, and a movable contact arm to cooperate with said contact ter minals, of a ratchet member rigidly associated with Said movable arm, independent and duplicate operating mechanisms em bodying electro-magnets adapted to cause movement of said ratchet member in opposite directions, make and break devices associated with each operating mechanism and normally arranged to close the energizing circuits of the respective electro-magnets,

electro-magnetic means tending to maintain said devices closed and means associated with said operating mechanism for positively opening and positively closing said make and break devices subsequent to the operative movement of said mechanism.

4. In a rheostat, the combination with cooperating stationary and movable contact members, and resistance elements associated therewith, of a ratchet wheel associated with the movable member, independent operating mechanisms embodying electro-magnets for actuating said wheel in opposite directions, and make and break devices electrically associated with said electro-magnets and embodying cooperating movable and stationary contact terminals, and electro-magnets normally arranged in series circuit with said operating electro-magnet's and said cooperating contact terminals and adapted to maintain engagement of said cooperating terminals, said operating mechanisms being adapted to effect the initial separation of said contact terminals subsequent to the movement of said ratchet wheel.

5. The combination with a rotatable member, a ratchet wheel attached thereto and independent electricallv operated means for intermittently actuating said wheel in either direction, of adjustable means for regulating ,the speed of operation in either direction, means for securmg a uniform speed of oper- 7 The combination with a rotatable member and means for intermittently actuatingsaid member, of means for regulating the speed of operation thereof, and means in'-' eluding an intermittently energized coil and actuated solely by said first means for maintaining a uniform step by step rotative movement.

8. In a rheostat, the "combination with a plurality of stationary contact terminals, a plurality of resistance elements connected thereto and a movable arm to cooperate with said contact terminals, of an adjustable electrically operated means for intermittently actuating said contact arm and intermittently energized electromagnetic means and a positively actuated circuit controlling means for governing the operation of said electrically operated means.

- 9. The combination with a rotatable member and an operating mechanism therefor embodying a working electro-magnet, of a make-and-break device embodying cooperating contact terminals and an auxiliary electromagnet both normally connected in series withsaid working elec'tromagnet.

10. The combination with a rotatable member and an operating mechanism therevior embodying a working electro-magnet, of.

a make-and-break device embodying cooperating contact terminals in series circuit with said working electro-magnet and electromagnetic means included in the same circuit tending to maintain said contact terminals in engagement.

In testimony whereot, I have hereunto subscribed my name this 18th day of February,

HARRY F. BETHUNE. -Witnesse s: v

H. G. YoUNGBLooo, KANUTH BUCHANAN.

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