US2472959A - Elevator control mechanism - Google Patents

Description

ELEVATOR CONTROL MECHANISM Filed Oct. 2, 1947 FUSES 66 52 ATTORNEYS Patented June 14, 1949 UNITED "STATES PATENT OFF ICE ELEVATORICONTRJOL MECHANISM :GeorgesD. Fettengill, ThomasaF. J arvis,and Williami L. Fader, Warsaw, N.'Y., 'assignors to War- :saw Elevator 00., Warsaw, N. Y.

Application October 2, 1947,'Serial No. 777,396

ell-Claims.

This invention relates to improvements in electrically powered elevator drive mechanisms; the

term elevator as -used-herein being intended to employ relatively low-speed single speed'or two-speed alternating current motors or direct current motors with suitable speed control accessories, such motorsandcontrol equipment are relatively costly compared to standard type higher speed (singlespee'd) alternating current motors. Such standard motors are unsuited for use in connection with 'the'prior-elevator drive designs because of their slow-down characteristics when high speed'elev-ator performance is prescribed. Hence, it" 'has'heretofore been necessary to employ the more expensive types of motors and speed control accessories for elevator drive purposes. 'Anotherdisadvantage attendant the use of such-prior elevator drive designsis that they do not lendi'themselves tojgood advantage to certain brakingtechniques'such as would reduce the friction braking requirements on the drive system incidental to service stops and automatic leveling procedures.

It is an'object of i the present invention to provide an improvedtype of elevator-electric drive and braking mechanism which embodies" an improved motorand traction sheave interconnection means of such character as to provide overall improved elevator car starting acceleration and braking deceleration characteristics, while-employing the most economical type electric motor and speed reduction gear devices.

Another object of the invention is toprovide an improved elevator drive mechanism which provides a smoother starting operation while imposing lower inrush currents 'on the driving motor windings.

Another object of the inventionis to provide Jto'bring the elevator car to astop, 'wherebyzonly a relatively light duty frictional :brake need :be

supplied for holding'the car whileat rest.

'Another object of therinvention is to "provide an improved elevator 'driving "and :braking :sys-

tern which is fully controllable through means'of a simplified control arrangement.

Another object of the'invention is to J provide a new and improved drivingmotorcoupling arrangement in electrical elevator drives 'andthe like, wherebyto obtain smoother starting and stopping of the elevator 'car.

Other objects and advantages of the invention will appearfrom the specification hereinafter.

In order toattainthepbjects'and advantages set forth hereinabove the inventioncontemplates an elevator drive unit comprising a relatively low cost single win'dingtype 'A. C. motor of suitable horsepower; a traction type'l'torquetransmitter connecting the motor to the load; anelevator traction sheave or drum; suitable holding''fric- 'tion brake means acting 1 upon means geared'to the traction wheel; and'where necessary, a suitable speed reduction gear unit interconnecting i the driven portionof'the torque transmitterand the traction-sheave. "Withinthe concept OfilthB present invention it 'is essential that 'the :motor "be adaptable to A. C. plugging serviceythat is; it may be suddenly reversed-as to'phase relation,

and 'that'the torque transmitter be -adapted"to slip while themotor is coming up to "speed so as to avoid excessive inrush of starting currents through the motor windings, and to avoid uncomfortable acceleration of "the elevator car. It is also essential "thatthe torque transmitter 'be of such nature as to'impose high drag forces from the plugged motor upon the traction sheave system during the initial high speed stage of elevator car deceleration preliminaryto a stopping operation; and it'is further essential,"for

the purposes of the invention, that thetorque purposes only. The torque transmitter may be of some suitable traction type, such as for example a fluid coupling device employing the hydrokinetic principle or a hydraulic system of the torque converter type, or an electromagnetic clutch, or a suitable variable slip mechanical clutch, or the like. However, we presently prefer to employ for this purpose a fluid coupling device because of its mechanical simplicity and ruggedness and economy and ease of operation, as well as because of its operational characteristics which so particularly adapt it to the problem as will be explained more fully hereinafter.

Referring now to the drawing, the single figure is a diagrammatic representation of an elevator driving and braking and control mechanism embodying the invention; and as illustrated therein the elevator car I6 is suspended by a cable 12 running over a traction sheave l4 and counterweighted at its opposite end as indicated at I6. The traction sheave I4 is fixed to a shaft l8 which is in turn fixed to gear 20 meshing with a worm 22. The worm 22 is driven by a shaft 24 which connects at its other end to the driven element of a traction coupling device which is illustrated generally at 25. The driving element of the traction coupling 2 is fixed to the armature shaft 26 of the elevator driving motor 36. The motor 36 is illustrated herein to be of the three-phase single speed A. C. type, and an e1ectromagneti-. cally actuated friction brake 32 is shown as being applied to the drive shaft 24.

In the drawing the circuits carrying power to the motor 36 are shown in heavy lines, commencing with supply mains 34-35-36 and thence leading through circuit controlled relays, the operation of which will be explained fully hereinafter. It will of course be understood that the invention is applicable to various types of driving motors and control systems, and that the drawing herein purposely illustrates only a relatively simple or basic motor control system providing minimum elevator control features. Thus, the drawing herein shows a control system embodying the usual hatchway door contact switches; F

an elevator car gate switch; an elevator speed governor switch; normal limit switches; terminal limit switches; a car safety switch, and the usual manual control switch in the elevator car. How ever, further accessory features may be readily added to the control system shown in the drawing herein as will be readily understood by those skilled in the art, so as to include for example automatic operation from hall buttons, automatic leveling, automatic door operation, and so on.

Referring again to the drawing; whereas the power circuits are shown in heavy lines, the control circuits are shown in lighter lines, and the manual car control switch is indicated at 46 as comprising a lever pivotally mounted on the elevator car wall. The lever 46 carries a conducting segment 42 which, when the lever is in its neutral position interconnects contact terminals 44-46- 48 of the control circuit. Commencing at the lower left hand corner of the drawing, it will be seen that a control circuit feed is picked up from supply main 35 by a control conductor to which includes in series therewith an appropriate number of hatchway door contact switches, depending upon the number of doors in the hatchway. In the drawing, for purposes of illustration, it is indicated that there are three doors in the hatchway equipped with door contact switches, as indicated at 52-53-54, respectively. The conductor 56 also includes the elevator car gate contact switch 55 and then terminates at a normally open terminal 56 of a sequence control switch 66. The switch 60 is actuated by a relay coil 62 as will be explained hereinafter.

The second control circuit feed originates at supply main 36 and leads therefrom through conductor 64 and through the usual governor switch 65, and thence through the upper terminal limit switch 66 and thence through the lower terminal limit switch 68 and thence through the car safety switch 16 to the controller terminal contact 48. The contact terminals 46-48 of the controller switch are interconnected by a conductor 12, and hence the second control circuit continues on through terminal 46 and through conductor 14 to a second normally open contact 16 of the sequence relay switch 60. Another conductor 18 leads from the contact 16 to the terminal armatur i9 of a two-way normally open motion responsive switch 66. The armature of the switch 86 is connected such as by means of a friction coupling device 8| of the fluid coupling type to a shaft 82 which is in turn geared to the elevator traction sheave shaft as by means of a sprocketchain system 84. Hence, whenever the elevator traction sheave shaft is rotating in one direction the armature of the switch will .be thrown over against one of either of the contact terminals 86-88 of the switch, while upon reversal of the direction of shaft rotation the switch armature will be thrown over against the other contact terminal of the switch. However, when the shaft is stopped the armature of the switch 86 moves to its neutral or non-contacting position, as under the influenc of spring means 89.

Thus, it will be seen that when the car controller 46 is in its neutral position, as shown in the drawing, the segment 42 thereof interconnects the contacts 44-46-48 thereby creating a control feed from either terminal 46 or 48 to ter minal 44 which is connected through conductor 96 to the relay coil 62 of the sequence control switch 60. Thus, when all of the hatchway doors and the elevator gate are closed (with the car controller in neutral position) the relay coil 62 is energized and lifts the switch device 6!] so as to bridge the contacts thereof. By means of the lower pair of contacts of the switch the circuit of the relay coil 62 remains energized and the relay switch holds itself closed, while the bridging of the upper pair of contacts of the relay switch provides feed for the motor control relay coils 92-94-96.

Thus, if the car controller handle 46 is moved over to the up position the segment 42 will clear the contacts 44-46 and will interconnect the contact 48 with another contact I66, thereby providing a closed circuit from terminal Hi0 through conductor I62, and thence through the upper normal limit switch I64 and thence to contact I66 of a normally closed relay switch I08 and thence through the relay coil 92 of a relay switch I [0. This will energize the coil 92, thereby lifting the relay switch l l6, whereupon the upper power control contacts thereof will close. At the same time the auxiliary contacts at the bottom of the switch I ID will close, providing a closed circuit to the relay coil 96 on the relay switch I I2. This lifts the switch I l 2, whereupon it will be seen that the power control contacts of switches I I0- I I2 are both closed, whereby a three phase power supply is established to the motor 30 through Dower conductors I l3-l I l-l l 5. The motor will thereupon turn to drive the elevator sheave l4 to raise the elevator car, the motor torque being transmitted through the fluid. coupling The fluid coupling device 25 thereupon operates to provide a particularly soft acceleration effect because of its inherent tendency to slip at slow speeds and to gradually increase in torque transmitting efficiency as the speed increases.

As illustrated in the top center portion of the drawing, the electro-magnetic brake device 32 is automatically energized coincidentally with energization of the motor 38 through conductors l |-8--l 4'? leading from two of the motor terminals. The conductors ll6li'i connect to a rectifier H8, the output terminals of which connect through conductors liiill2i to the coil of the electromagnetic brake device 32, whereby D. C.

current is supplied to the brake'coil whenever the motor '36 is energized. The brake device 32 comprises; for example, a, spring-actuated friction band or block brake with the coil magnet thereof arranged to release the bi eke whenever the motor isenergised. Thus, the brake device 32 automatically sets whenever the power to the motor is interrupted.

The upward travel of the elevator car may, of

course, be interrupted either by contact of any suitable member extending from the car, such as a cam, with the upper normal limit switch arm, or by manual movement of the control handle 4!! away from its up position. Assuming, for example, the control handle to have been returned bythe operate; to its neutral position, the feed through the segm nt t2 between the contacts 48l t3 is thereby interrupted, and the circuit including the coil $2 in the up travel relay unit is now deenergized. Momentarily, inertia of the car and the drive mechanism will continue the upwar travel of the car, and therefore the armature oi the traction switch 30 is still biased to keep the up travel contacts closed. Thus, the feed from the controller contact 46 forms a closed circuit through the conductors M 18 and the traction switch 89 and the conductor i2 l and the contact 52% of the relay switch I ll As the switch i it drops, due to deenergization of the coil 92 as explained hereinabove, the circuit through the contact lid is thereupon completed through switch contact E28, conductor I38, controller contact i222, and thence through the lower normal limit switch its, and then back through conductor i355 through contacts 238-439 of the relay switch lid, to the coil 95 of the down control relay switch 168, and thence through contacts l4t55 of the switch 60 and thence through conductor 58 to the supply main 35.

Thus, the clown control relay switch I08 and the main line conductor switch I 12 are both lifted, thereby completing a three-phase power supply to the motor 39, but in reverse phase relationship to the direction of the previous operation of the motor. The motor is thereby plugged or reversed, and drags upon the elevator drive mechanism to decelerate the latter in the manner of a braking device; the traction coupling device 25 permitting varying rates of slip between the motor and the elevator traction sheave, depending upon the relative speeds thereof.

It is with respect to this braking performance of the motor 3i during deceleration of the elevator car travel that the novel torque transmitting characteristics of the traction coupling device, such as for example of the so-called fluid coupling type, become manifest and provide an improved electrical braking or plugging performance when using a motor of the relatively however, the

economical singleespeed A..C. type. For example, when the controller is moved to neutral position the driving mechanism is at first traveling at relatively high speed, and the tendency of the 5 traction sheave end of the drive mechanism to overrun the motor end of the mechanism is'at first strenuously. resisted because of the nature of the operation of. the fluid coupling device at high speeds. Thus, at this stage the motor imposes a high degreeof drag upon the drive mechanism, thereby tending to quickly brake the car travel. However, as the rate of car travel is reduced', the coupling 25 becomes less efiicient as a torque transmitter, and a progressively softening dragging efiect is supplied by the motor to the traction sheave; with the result that as the elevator car slows down and approaches the stop thedeceleration rate smooths-01f, thereby avoiding violent deceleration shock in connection with the stopping operation.

In event the inertia of the elevator car and driving mechanism is suflicient to continue to carry the car upward even after the motor 30 comes to a stop, the motor will of course then commence to rotate in reverse direction, thereby maintaining arelative speed between the driving and driven elements of the traction coupling 25 so as to continue to impose the desired braking drag upon the traction sheave end of th mechanism. In any case when the traction sheave is brought to rest the traction switch 80 will open, thereby interrupting the circuit to the contact 1% and the circuit to the relay switch coil 94, permitting the switch I98 to drop. This interrupts the power supply to the motor and to the electro-magnetic brake 32, whereupon the latter is mechanically applied to hold the elevator car at rest.

It will be appreciated that if, instead of manual return of the controller to neutral position as explained hereinabove, the elevator car is permitted to rise until the car cam opens the upper normal limit switch I04, the circuits to the coil 92 of the switch III will be interrupted; and that the switch 89 will thereupon assume control of the system to cause reversal of the motor so as to effect the braking action explained hereinabove and to finally stop the elevator car with the mechanical brake applied.

Downward car travel control is effected by the mechanism illustrated upon manual manipulation of the controller into its down position as shown in the drawing, whereupon the control circuits are completed to energize the down relay and the main line switch H2 to complete a three-phase power supply to the motor in reversed phase relation. The switch 88 then closes in the clown direction upon starting of the elevator travel upon centering of the car control handle 40, or opening of the lower normal limit 60 switch I34, the relays lll8ll2 will be deener:

gized, whereupon control circuit feed will be established through switch 86 and conductor M5 to the coil 92 of the up relay I It, which will in turn energize relay H2 and cause the motor to be plugged. The elevator mechanism will be thereby braked as explained hereinabove until it comes to rest at which time the armature of switch 88 assumes its neutral position. The control circuit feed is then broken to the up relay H9, which then falls out and deenergizes the motor 3|) and causes the brake 32 to be set.

Thus, it will be understood that it is a particular feature and advantage of the invention that acceleration of the elevator car travel is acquired through a traction-type coupling which prevents violent acceleration effects, and that braking of the car travel is acquired by "plugging the single speed A. 0. motor and transmitting the drag therefrom to the elevator traction sheave through the traction coupling device which delivers in improved manner a counter-torque operating to retard and stop the car. Thus, a nearly constant rate of deceleration is obtained, and although the driving motor may even be running in reverse direction when bringing the elevator car to a stop, no violent deceleration efiects are experienced, and the car comes to a soft stop because of the braking characteristics of the plugged motor operating in cooperation with the novel coupling element of the driving system.

What is claimed is:

1. In an elevator drive and braking control system, a reversible alternating current electric motor, an elevator drive shaft, a fluid coupling device interconnecting the drive shaft of said motor and said elevator drive shaft, and a power supply control system for said motor including manual switch means operable to cause energization of said motor, switch means operable to reverse said motor to impose a counter-torque through said coupling device to halt the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

2. In combination, an elevator, a reversible alternating current electric motor, a traction type coupling device interconnectin the drive shaft of said motor and said elevator for moving the latter, and a power supply control system for said motor including manual switch means operable to start said motor to run in either direction and operable to reverse said motor while running to impose a counter-torque through said traction coupling device to halt the elevator travel, and switch means operable automatically upon halting of said travel to deenergiz said motor.

3. In an elevator drive and braking control system, a reversible alternating current electric motor, an elevator drive shaft, a fluid coupling device interconnecting the drive shaft of said motor and said elevator drive shaft, and a power supply control system for said motor including manual switch means operable to cause energization of said motor, switch means operable to reverse said motor when running to impose a counter-torque through said coupling device to halt the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

4. In an electric drive and braking system for elevators, a reversible alternating current motor, an elevator drive member, a traction type coupling device interconnecting the drive shaft of said motor and said elevator drive member, and a power supply control system for said motor including switch means operable to cause energization of said motor, switch means operable to reverse said motor when running to impose a counter-torque through said traction coupling device to brake the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

5. In an elevator drive and braking control system, a reversible alternating current electric motor, an elevator drive shaft, a fluid torque converter interconnecting the drive shaft of said motor and said elevator drive shaft, and a power supply control system for said motor including manual switch means operable to cause energization of said motor, switch means operable to reverse said motor to impose a counter-torque 8 through said'converter to halt the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

6. In combination, an elevator, a reversible alternating current electric motor, a torque converter coupling device interconnecting the drive shaft of said motor and said elevator for moving the latter, and a power supply control system for said motor including manual switch means operable to start said motor to run in either direction and operable to reverse said motor while running to impose a counter-torque through said traction coupling device to halt the elevator travel, and motion responsive switch means operable automatically upon halting of said travel to operate to cause deenergization of said motor.

7. In an elevator drive and braking control system, a reversible alternating current electric motor, an elevator drive shaft, 21. fluid torque converter interconnecting the drive shaft of said motor and said elevator drive shaft, and a power supply control system for said motor including manual switch means operable to cause energization of said motor, switch means operable to reverse said motor when running to impose a counter-torque through said converter to halt the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

8. In an electric drive and braking system for elevators, a reversible alternating current motor, an elevator drive member, a fluid torque converter device interconnecting the drive shaft of said motor and said elevator drive member, and a power supply control system for said motor including switch means operable to cause energization of said motor, switch means operable to reverse said motor when running to impose a counter-torque through said fluid torque converter to brake the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

9. In an elevator drive and braking control system, a reversible alternating current electric motor, an elevator drive shaft, a torqu connecter interconnecting the drive shaft of said motor and said elevator drive shaft, and a power supply control system for said motor including manual switch means operable to cause energization of said motor, switch means operable to reverse said motor to impose a counter-torque through said connecter to halt the elevator travel, and means operable automatically upon halting of said travel to deenergize said motor.

10. In combination, an elevator, a reversible alternating current electric motor, a torque con necter device interconnecting the drive shaft of said motor and said elevator for moving the latter, and a power supply control system for said motor including manual switch means operable to start said motor to run in either direction and operable to reverse said motor while running to impose a counter-torque through said connecter device to halt the elevator travel, and switch means operable automatically upon halting of said travel to deenergize said motor.

11. In an electric drive and braking system for elevators, a reversible alternating current motor, an elevator drive member, a hydrokinetic fluid coupling device interconnecting the drive shaft of said motor and said elevator drive member, and a power supply control system for said motor including switch means operable to cause energization of said motor, switch means operable to reverse said motor when running to impose a 10 counter-torque through said coupling device to REFERENCES CITED brake the elevatbr travel, and means operable The following references are of record in the automatically upon halting of said travel to file of this patent,

deenergize said motor.

GEORGE D. P NGILL- 5 UNITED STATES PATENTS THOMAS F. JARVIS. Number Name Date WILLIAM L. FADER. ,6 Ayres Dec. 7, 1937

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