Patent GB-633412-A (GB)
Title: Improvements in or relating to elevator systems
IPC: B66B1/52
Filed: 1946-06-24
Abstract: 633,412. Control of motors. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. June 24, 1946, No. 18896. Convention date, June 25, 1945. [Class 38 (iii)] [Also in Group XXXVIII] In a elevator system the controller is operated under the control of the floor selector to accelerate the car in a series of predetermined tuned steps and to decelerate it to floor level, means also being provided responsive to the operation of the controller and to the position of the car to stop it at the selected floor. General operation.-Fig. 3. When the attendant operates the starting button a motor AM drives through a differential K2, the shaft 30 of which is braked at this stage to operate the levelling controller L to its " on " position, thereby cutting resistance out of the field of a Ward-Leonard generator supplying the hoising motor. Simultaneously the carriages of a floor selector which are mounted on opposite runs of an endless chain are given a lead corresponding to 20 inches on the car by way of the ring gearing 227, Fig. 13, of another differential K1, the output of which drives the floor selector. As controller L reaches its full " on position the brake is transferred to the shaft of controller L and motor AM drives the main controller M to its " on " position shorting out field resistances and connecting the hoisting motor to its supply. The hoisting motor then accelerates under the control of speed relays which cut resistance out of the generator field. An electric synchronous link SM driven by the hoisting motor adds its motion to that of the motor AM to give the carriages a lead on the car corresponding to 20 feet. When controller M reaches its stops the motor AM is stalled and the carriages move in synchronism with the car. As the carriage closes contacts prepared by the call-buttons however a pawl is energized to lock the carriage whereupon the synchronous motor drives controller M to its " off position so as to decelerate the car. When the car reaches a point 20 inches from the floor an inductor relay operates its contacts to brake the controller M and release fine controller L so as to decelerate the car very gradually to a standstill. Detailed operation. Starting.-For simplicity the bottom floor will be called the first and so on and the figures relate to floors 10 feet distant from each other. Assume that a seventh floor up call button 7 UB is pressed to call a car which is standing at the first floor with its doors open. A " no hall-call above relay 78 is then deenergized and an up call registering relay 7UR is operated to prepare circuits which will cause the stopping of the car at that floor. Operation of a car starting button CS energizes a starting relay 80 and thereby a brake transfer magnet TM which locks the shaft of coarse controller M and releases L. Relay 80 causes operation of an up direction relay U which locks itself, energizes a direction preference relay W and connects the generator field to the supply as at contacts U2 and U3. Relay 80 also energizes a door operating relay 45 and sets the advance motor AM in operation. As previously stated this motor rotates controller L to its " on " position by driving shaft 166, Fig. 13, differential K2 and controller drum shaft 188 and gives the up carriage a small lead by ring 227 of the differential Kl and output shaft 159, synchronous motor SM being at rest. Controller L short-circuits resistances Rll, R10 and R9 in the generator field then transfers the brake to its own shaft releasing M, and de-energizes the advance motor. When the lift doors close their safety contacts, main and auxiliary door safety relays 40 and 22 energize and finally a pre-energization relay 7 which connects the motor to its supply. Relay 40 sets the advance motor in operation again. By the time the motor gets under way the carriage has a lead corresponding to about 1 floor. Controller M then initiates the successive energization of speed relays GR4, 6 and 8 which cut resistance out of the generator field their speed of operation being determined by the drop-out time of delay relays GR6T and GR8T. The car accelerates to full speed. The motion of the synchronous motor is added to that of the advance motor in the differentials K1 and K2 so that the carriage has a lead on the car corresponding to two floors. Controller contact M13U inserts resistance R14 in series with the advance motor AM and then engages limit stop and stalls this motor so that the carriage continues up at a speed proportional to the car speed. Stopping.-As the carriage moves up a roller carried by it, lights a lamp in the position indicator while further rollers close contacts such as TS4, Fig. 22, to energize a stopping relay 438 and contacts 7UR1 are already closed by the call registering relay 7UR. Holding coil 438H also locks and operates the up pawl magnet UPP which stops the carriage by engaging another roller with fixed lugs mounted in the floor selector. Since the up carriage is locked, synchronous motor SM drives the advance motor AM backwards and commences to rotate controller M from its " on " to its " off position. As the controller opens it de-energizes the speed relays inserting resistance in the generator field and energizes the inductor relays UF and DF. When the car is a short distance from the floor all resistances up to R8 have been inserted. At this point the inductor relay UF is brought near a plate of magnetic material in the lift shaft and closes its contacts energizing an up stop relay UE and a clutch magnet control relay H. The latter operates a clutch to disconnect controller M from the differential and at the same time forces a pin 34 into a slot on the controller to centralize it. Contact H4 transfers the brake from controller L to controller M. Controller L inserts further resistances in the generator field to decelerate the car very gradually and energizes door safety relays 22 and 45 to start the doors opening. When the car is at a very short distance from the floor (say # inch) the inductor contacts again open and de-energize relays H and UE and hence the clutch magnet CM, M being braked however remains at rest. Relay UE de-energizes the up-direction relay U and the running relay 6. U de-energizes the hoisting motor the auxiliary levelling relay 65 and the hoisting motor brake coil 15a to apply the brake to stop the lift. After a time lag relay 32T falls out and de-energizes pre-energizing relay 7, disconnects the motor from the generator and inserts a resistance R1 in series with the generator armature for series field energization. Finally de-energized relay 43T applies brake 27 to the controller L and releases controller M. Car reversal.-When a car is at a floor and there are no calls above it the car is automatically reversed on operation of the start button by means of a relay 38R. Suppose the car proceeds to floor 10 as a result of operation of the car button 10C when it is held by its holding coil CC and energizes relay 38R to prevent reversal of the car. As in the previous operation controllers L and M are rotated to " on " positions and the car moves upwards. When the up carriage locks at the 10th floor however the up lantern 10LMU is not illuminated because contact 38R6 of relay 38R is open. The down pawl magnet DNP is energized however, by the circuit L43, 38R5, W6, 45-2, UPP2 and 38R4 so that the down lantern is lit to indicate that the car will reverse. When the car is decelerated to a stop at the floor as in the previous case contacts 32T2 in series with the up direction preference relay W open and in consequence direction preference relay X is energized via the back contact of W and contact 38R2 of relay 38R. Thus the next operation of the car button causes the car to move downwards. It is stated that any number of cars may be added to the system described by adding contacts and signal circuits for each car and connecting their hall call cancellation contacts to the cancellation coils such as 2UNR of the hall call registering relays. Re-levelling-for an overrun or for a stretched cable.-If a car is standing level at a floor and say a large number of persons leave it causing it to rise above floor level contacts DF1 of inductor relay UF are closed closing the circuit of the down direction relay D and running relay 6 and energizing the generator field. Relay 6 energizes relay 7 which closes the loop circuit to the motor and releases the brake. The car now moves slowly downwards until contacts DF1 are again opened. Neither controller has been operated. If the car overruns the floor by a considerable distance, say 7 inches, contacts DF1 of the inductor relay are again energized thus energizing the clutch control relay H and the auxiliary down stopping relay DE. It prevents energizing of the transfer magnet TM, that is only controller L is free. The advance motor AM is also energized but this is overridden by the upward movement of the car which rotates L past its mid-point to one of the " down positions depending on the amount of overrun. Energized relay DE energizes the down direction relay D and the car running relay 6 excites the generator field and since relay 7 has not yet de-energized the car moves back as for a normal arrival at a floor. Express operation. Fig. 23. When a car is not required to stop at any of say the first 14 floors the floor selector may be simplified by the removal of the blocks of contacts corresponding to the floors intermediate between the first and 15th floors and the insertion instead of an up and down express contact blocks and stop lugs. The carriage runs ahead of the car as before until it engages these contacts which are situated a distance proportional to two and a half floors from the end of the express zone which the car has left. The carriage then locks on this lug and is held until operation of an inductor relay about three floors from the end of the express zone releases the carriage to carry