Patent GB-679999-A (GB)
Title: Improvements in or relating to multi-car elevator systems
IPC: B66B1/18
Filed: 1950-08-17
Abstract: 679,999. Electric elevator systems. WESINGHOUSE ELECTRIC INTERNATIONAL CO. Aug. 17, 1950. [Sept. 2, 1949] No. 20437/50. Class 40 (i). In a multi-car system in which the cars are despatched from upper and lower despatching floors to serve "down" and "up" demand respectively, the system is organized so that, under standard conditions, cars are despatched at regular intsrvals, but the normal interval is shortened when conditions depart from the ideal as follows: - (1) the top floor interval is shortened by one amount if two cars are at the top floor and by a larger amount if three or more cars are at the top floor (2) the top floor interval is modified in accordance with the relative "up" and "down" demands (3) with feature (1) disabled, a car is despatched immediately from the top floor with a certain volume of demand and no car in position to satisfy that demand readily(4) immediate despatch from the bottom floor is given with three cars waiting or with only two cars waiting if, in addition, either the top floor is working under "immediate despatch" conditions or a predetermined number of floorbuttons areoperated in the"next" car at the bottom floor (5) immediate despatch from the top floor may be similarly controlled by the despatching arrangements of the bottom floor or by the operated car buttons in the"next" car at the top floor. Operating under standard conditions. In this case one car arrives at the top floor as another leaves and there are no cars waiting. The "top floor" relay AU ... DU of the recently arrived car will be energized and the "next" relay AN ... DN of the car that has just left will have fallen back. Clutch RC is thus operated to drive the cam 41 operating the distributor AY ... DY. When the contacts of the waiting car are closed, a circuit is made for its "next" relay AN, DN which releases the clutch and lights lamps to indicate that the car in question will be the next to leave. When the previously despatched car left, its relay AU ... DU fell back, releasing its individual starting relav AS ... DS and so operating the clutch SC of a timing switch 43. When the latter closes its contacts, 1S is operated and locks and the time switch returns to normal. At the same time a timing relay 2S, shunted to make it slow-torelease, is disconnected. On the relapse of 2S a similar timing relay 3S is disconnected and, when this falls, a common starting relay US is energized. This energizes the individual starting relay AS ... DS of the allotted car to give the starting signal to the attendant to release the timing relay 1S and to extinguish the "next" signal lamps AHL, DHL, ANL, DNL and release the "next" relay AN ... DN. The timing interval is measured out also when there is no car at the landing and when a car does arrive it is despatched on the expiry of the normal interval or as soon as it is allotted, whichever comes later. Similar arrangements may be provided at the lower despatching floor. Reducing despatching interval in response to bunching. A reduction of demand causes the cars to bunch at the despatching floors. With (say) two of the top floor relays AU ...DU energized the current through 2E is enough to energize it and with (say) three cars at or near the floor 3E is able to pull up. With 2E energized, the common starting relay US is energized immediately on the relapse of 2S and the despatching interval is thus reduced by the release time of 3S. With 3E energized, the interval is shortened by the release time of both these relays. The shortening of the time interval may be brought about by the arrival of a car, and in this case the despatching interval may be shortened by something less than the release time of 2S or 3S since the car may not arrive and 2E or 3E may not operate until 2S or 3S has already begun to release. The result of these arrangements is that if at anytime (say) three cars are at the despatching floor, the first is despatched after a short, the second after a medium and the third after a long interval and hence bunching is corrected. This facility is provided in a different way in a system described below for modifying despatching arrangements in accordance with demand. Modifying despatching interval in accordance with relative "up" and "down" demands. "Up" call register-relays put resistors 57, Fig. 3 in parallel in series with one control-winding 59 of an electromagnetically controlled resistor and "down" call register-relays similarly control the oppositely acting winding 63. The position of the slider on the resistor thus depends on the relative "up" and "down" demands. The resistor may replace the resistor 47 or 49 in Fig. 2 which controls the release time of relay 2S or 3S. Modifying top floor despatching arrangements in accordance with demand. In the system described, this is mainly concerned with accelerating despatch from the top floor in response to "down" demand, but similar arrangements could be provided in connection with the ground floor despatching system. When this facility is in use, switch 51 Fig. 2 is opened to disable the previously described arrangement for expediting despatch in response to bunching. The building is assumed to have 17 floors divided into four zones. The presence of a downgoing car in the zone of the floors 14 ... 16 is indicated by the operation of relay P1 over floor selector terminals and wipers 81, 82. Similarly relays P2, P3 indicate the presence of down-going cars at the zones including respectively floors 10 to 13 and floors 6 to 9. A car at the lowest floor of one zone operates also the relay P of the zone below. When relay 1DU is energized, it operates the common starting relay US to cause the allotted car to be started immediately without regard to the operation of the timing system. The conditions bringing about the operation of 1DU are as follows (1) With shunt 72 connected up, the presence of three or more cars at or near the top landing (2) with shunt 72 disconnected, the presence of two cars at or near the landing. (The shunt can be disconnected by the energization of UT, which is operated by the immediate despatch relay 1DL of the low despatching floor, or by the relapse of K. The latter is brought about by the operation of any one of the zone call register relays R1 ... R3 (but not R0 of the top zone) unless the position relay P1 ... P3 of one of the zones above is operated and even if the relay P of the zone above the highest call is operated, K is released if the relays R of two zones (other than the top zone) are operated together. A zone register relay is operated by a call in two or more of the floors of the zone, unconditionally in the lowest zone and provided that there is no car actually travelling in the zone in the case of the others. This exception is nullified in the case of zones 2 and 3 if the register relay of one of the zones below is operated and there is not an additional car able readily to meet the additional demand. It will be observed that the register relay of the top zone is called R0, that of the second R1 and so on whereas the position relay of the top zone is called PI that of the second, P2 and so on). (3) Irrespective of the presence or absence of shunt 72, if the register relays R0 ... R3 are operated and the position relays P1 ... P3 are unoperated in certain combinations. (The operation of RO by itself is without effect., but jointly with R1 it operates 1DU unless P1 is operated because a car is serving the top zone. Similarly R2 with either R1 or R0 operates 1DU unless P1 or P2 is operated and R3 with either R1 or R0 is effective if none of the relays P is operated. Also R2 and R3 together are effective if neither P2 nor P3 is energized). Bottom floor arrangements. As shown, the bottom floor despatching arrangements are not responsive to "up" demand but otherwise resemble those at the top floor. An instant despatch relay 1DL is operated (1) by the presence of two or three cars at the floor according as T or LT is or is not operated. T is operated when 1DU of the upper despatching system operates, provided that K has been released, and locks under control of the ground floor start relay LS. LT is operated when the car allotted to start next from the ground floor has a predetermined number of its floor selecting buttons operated so as to energize the corresponding relay ACC ... DCC. When 1DL is operated as well as LT it energizes UT to remove the shunt from 1DU. UT locks until the next car leaves the upper floor. The upper floor despatching arrangements may be similarly controlled by floor demand from the allotted car.