US3746131A

US3746131A - System for controlling a plurality of elevator cars

Info

Publication number: US3746131A
Application number: US00189347A
Authority: US
Inventors: K Hirasawa; K Kawatake; T Iwasaka
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1970-10-19
Filing date: 1971-10-14
Publication date: 1973-07-17
Anticipated expiration: 1990-07-17
Also published as: GB1358903A; DE2151272A1; JPS5117777B1

Abstract

A system for controlling a plurality of elevator cars in which a hall call originating means is disposed at each floor landing so that passengers standing at the floor landing can designate the floors to which they want to be transferred, and a target floor memory is provided for each elevator car to store information as to the floors at which such elevator car has already been instructed to stop. In the system, means are provided to detect the coincidence between the floor numbers designated by a hall call originating from one of the floors and the floor numbers stored already in the target floor memory for each elevator car so that the elevator car for which the coincidence occurs in a greater number can be preferentially selected to be stopped at the specific floor.

Description

United States Patent 1191 Hirasawa et al.

1111 3,746,131 1451 July 17, 1973 SYSTEM FOR CONTROLLING A PLURALITY OF ELEVATOR CARS Inventors: Kotaro Hirasawa; Koichi Kawatake, both of Hitachi-shi; Tatsuo lwasaka, Katsuta, all of Japan Primary l' xaminvr-- Bernard A. (illhCZllIy Assistant Examiner-W. E. Duncunson, Jr. A!tmey-Craig, Antonclli & Hill [57] ABSTRACT Asystem for controlling a plurality of elevator cars in which a hall call originating means is disposed at each floor landing so that passengers standing at the floor landing can designate the floors to which they want to be transferred, and a target floor memory is provided [30] Foreign Apphcanon Pnomy Data for each elevator car to store information as to the Oct. l9, 1970 Japan 45/91184 floors at which such elevator car has already been structed to stop. in the system, means are provided to [52] 11.8. C1. 187/29 R detect the Coincidence between the floor numbers [51] hit. Cl B661) 1/18 ignated by a hall n originating from one of the floors [58] Field 01 Search 187/29 and the floor numbers Stored already in the target floor memory for each elevator car so that the elevator car [56] References and for which the coincidence occurs in a greater number UNITED STATES PATENTS can be preferentially selected to be stopped at the spe- 3,374,864 3/1968 Port 187/29 R fi fl 3,507,362 4 1970 Kuzara et al.. 187/29 R 3,443,667 5/1969 Hall et al. 187/29 R 6 Clam, 7 Drawmg Flames HALL CALCU- CALL LAT/N6 REGISTER $55? Haj"? i alvc/os/vcs 1 125E670? TEMm ears FAR) M4 -5 mm 6/ 45 MB SELECT 62 L0 Mua AC A/VC 624 -RUNA s T 40 AND 625 --/?U/VE OPT/MUM ELE 14470,? 626 -/?U/VO 504 C SELECTOR 5 G20 --RU/V0 509 0 Zi'Z-fi;

ru/v man FLOOR $06 MEMORY D Patented July 17, 1973 6 Sheets-Sheet 1 QR QQ Qm Q Q\ 353GB SGKRQQ R F. w H

g bm fi IILII at um b 9 mm mm 3 an hm b9 INVENTORS KOTARo HIRASAWA Kocm KAWATAKE.

TATSUO (WASAKA ATTORNEYS Patented July 17, 1973 6 Sheets-Sheet 2 INVENTORS KOTARO HIRASAWAJ OICHI KAWATAKE,

TATSUO IWASAKA 'Patented July 17, 1973 v 3,746,131

6 Sheets-Sheet 5 HALL I FROM m3 (0 00) T0 FF (OFCD) INVENTORS KOTARO HIRASAWAIKOICHI KAWATAKE TATSUO IWASAKA BY =6 ATTORNEYS Patented July 17, 1973 I 3,746,131

6 Sheets-Sheet 5 FIG. 6

FROM

FF/ FF2-- -FF// SWl/ FROM J HO? INVENTORS KOTA R0 HIRASAWA, o lCHl KAWATA K F,

TArsuo IWASAKA BY Qu aMtgult 17 um ATTORNEY Patented July 17, 1973 I 3,746,131

6 Sheets-Sheet 6 729 AND INVENTORS KOTARO HIRASAWA K0|H| KAWATAKE TATSUO IWASAKA BY Cram haw H-LQQ k ATTORNEYS SYSTEM FOR CONTROLLING A PLURALITY OF ELEVATOR CARS This invention relates to an elevator control system for controlling the operation of a plurality of elevator cars servicing a plurality of service floor landings.

In a building in which a plurality of elevator cars are in parallel operation for servicing a plurality of service floor landings, individual elevator cars should preferably be prevented from stopping at the same intermediate floors more than is required so that they can make one round trip within the shortest possible period of time thereby improving the service efficiency of the elevator system as a whole, hence shortening the passengers waiting time.

The reduction in the number of stoppages increases the operating speed of the elevator cars and eliminates the period of time required for the stopping, deceleration and getting on and off of the passengers thereby greatly improving the operating efficiency of the elevator system. Suppose, for example, that four elevator cars rated at a speed of 300 meters per minute are provided in a-building having ll floors for servicing the floor landings. Suppose further that the probability of an elevator car stopping at one of the intermediate floors is 0.4 meaning that an elevator car stops at the specific floor four times during round trips, that the elevator car is at rest at each such floor for 10 seconds, and that the distance between the floor levels is 3.5 meters. Then, the period of time required for the elevator car to make one round trip without stopping at any floors except the bottom terminal is given by (3.5 X 20/300) z 0.23 minute 14 seconds and therefore, the mean period of time required for the elevator car to make one round trip while stopping at these floors is given by 10 X20 X 0.4 14 94 seconds.

The mean period of time required for the elevator car to make one round trip can be reduced to 94 10 84 seconds 94/4 z 24 seconds and 84/4 21 seconds respectively. The means waiting time may be considered to be directly proportional to the mean arrival interval. Thus, when the elevator cars are prevented from stopping wastefully at one of the intermediate floors during one round trip, the mean waiting time can be reduced by about 12% due to the fact that the ratio of the latter mean arrival interval to the former mean arrival interval is Conventional methods for effectively reducing the number of stoppages of elevator cars include a method in which each individual elevator car has its own preset service zone which may be fixed or variable and the-response of the elevator car'to hall calls belonging to the service zones of other elevator cars is limited, and a method in which some elevator cars are arranged to respond solely to hall calls originating from specific floors, for example, odd-numbered floors or evennumbered floors. However, these conventional methods are limited in that they limit the response of the elevator cars to hall calls, and the results are substantially the same as when the number of servicing elevator cars is decreased thereby reducing the quality of service to the passengers.

It is an object of the present invention to provide a novel system for a plurality of elevator cars according to which elevator passengers can substantially simultaneously get on and off the elevator cars so as to reduce the number of stoppages of the elevator cars as much as possible thereby shortening the mean waiting time for the passengers and providing a better service.

In the control system according to the present invention, a hall call originating means of the type capable of designating the destination floors is disposed at each floor landing, and a target floor memory is provided for each elevator car so that it stores information as to the floors at which such elevator car has already been instructed to stop. In response to the origination of a hall call by the hall call originating means at one of the floor landings, coincidence detectors detect the coincidence between the floor numbers designated by the hall call originating from the specific floor and the floor numbers stored already in the target floor memories. The elevator car for which the coincidence occurs in a greatest number is selected and responds to the hall call originating from the specific floor so as to minimize the number of stoppages of the elevator cars as a whole. Consequently, the passengers waiting time can be reduced to a minimum and the desired improvement in the service can be realized.

Passengers standing at the specific floor from which the hall call is originated may wait a long period of time when the elevator car for which the coincidence occurs in the greatest number is quite remote from the specific floor from which the hall call is originated. 7

It is another object of the present invention to avoid an exceptionally long waiting time by arranging so that another elevator car, for which the coincidence occurs in a relatively large number and which is relatively near the hall call originating floor, can respond to the hall call in such a case.

To this end, distance detectors are provided to detect the distances between'the specific floor originating the hall call and the elevator cars so as to determine the priority order of these elevator cars taking the relative distances intoaccount. Further, in the case of the elevator car which must stop at more floors than others until it reaches the specific floor from which the hall call is originated, the actual running distance between it and the specific floor is large compared with others when its running schedule is taken into account although the physical distance between it and the specific floor is short. Therefore, the actual distances that must be travelled by the elevator cars should also be detected and taken into-account for determining the priority order of the elevator cars.

Other objects, features and advantages of the present invention will be apparent from-the following description taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a schematic front elevational view of a hall call originating means having a plurality of push buttons for designating the destination;

FIG. 2 is a schematic diagram'showing the running state of a plurality of elevator cars;

FIG. 3 is a block diagram showing the structure of an elevator control system embodying the present invention;

FIG. 4 is a circuit diagram showing the structure of one form of a hall call register I-ICR preferably used in the system shown in FIG. 3;

FIG. 5 is a circuit diagram showing the structure of one form of a calculating order control means CD preferably used in the system shown in FIG. 3;

FIG. 6 is a circuit diagram showing the structure of one form of a gate G1 preferably used in the system shown in FIG. 3; and 1 FIG. 7 is a circuit diagram showing the structure of one form of a coincidence detector A preferably used in the system shown in FIG. 3.

- An elevator system is well known in which a hall call originating means having a plurality of so-called hall buttons or destination registering push buttons capable of designating the destination floors is provided at each floor landing for an elevator car so that it replaces the destination floor register previously provided in the elevator cage, This hall call originating means has an external arrangement as shown in FIG] in which it will be seen thata plurality of destination registering push buttons H131 to H811 are provided so as to designate any one or ones of the first floor (bottom tenninal) to the llth floor of a building having 11 floors, and this replaces the conventional hall call register having an up registering and a down registering push button. The provision of such means is advantageous in that passengers need depress the destination registering push buttons in the cage again after they get on the elevator car.

The present invention utilizes a hall call originating means of the type described above and will be described with reference to FIG. 2. FIG. 2 shows an elevator system in which four elevator cars A, B, C and D are provided in a building having eleven floors for servicing these floor landings. In FIG. 2, the physical positions of the elevator cars are designated by 1U (up from the first floor) to U (up from the 10th floor)-when they move upward and by 2D (down from the second floor) to 1 1D (down from the eleventh floor) when they move downward.

According to the basic principle of the present invention, the coincidence between the floor numbers designated by a hall call originating from a floor and the floor numbers already registered in the memories for the elevator cars is detected, and the elevator car for which the coincidence occurs in a greatest number is selected so that the selected elevator car can be preferentially stopped at the specific floor from which the hall call is originated. Suppose, for example, that the hall call originating means disposed at the landing of the fourth floor designates and registers the sixth, seventh and eighth floors, and the elevator cars A, B and C moving upward as shown in FIG. 2 are instructed already to stop at the sixth, seventh and eighth floors, at the seventh and eighth floors, and at the seventh floor respectively. Then the elevator car A is selected to stop at the fourth floor from which the hall call is originated. This manner of elevator control is advantageous in that the elevator cars B and C need not stop at the fourth and sixth floors and at the fourth, sixth and eighth floors respectively so that their movement can be accelerated by that much, and yet the increase in the number of stoppages for the elevator car A responding to the above hall call is only one corresponding to the stoppage at the fourth floor.

FIG. 3 is a block diagram showing the structure of an embodyment of the present invention. The elevator control system includes a plurality of hall call registers HCR each disposed at the floor landings. The hall call register I-ICR is of the type shown in FIG. 1 so that pas sengers standing at the floor landing can designate their destination floors by depressing the corresponding push buttons. The operation of the hall call register I-ICR is such that the floor number at which the hall call register I-ICR is disposed is also automatically registered when anyone of the destination registering push buttons is depressed. For example, in the case of the hall call register HCRS disposed at the landing of the fifth floor, the call for the fifth floor is also registered when the push buttons for the floors other than the fifth floor are depressed.

In a preset period of time of, for example, 15 seconds after the hall call register I-ICR at one of the floors has been actuated, a signal is applied to a calculating order control means CD so that it starts its calculating operation. The calculating order control means CD is a common control means for all the hall call registers I-ICRl to HCRll, and therefore, a locking signal IS is applied from the calculating order control meens CD to the hall call resisters I-ICR except the hall call register I'ICR at the specific floor so that they may not apply their outputs to the calculating order control means CD. In a very short period of time, the calculating order control means CD applies a signal to open a gate G1 so that the information as to the floor numbers registered by the specific hall call register I-ICR is transferred to and stored. in a temporary memory LAT. Therefore, the temporary memory LAT stores the information as to all the floor numbers designated and registered in the hall call register I-ICR within about 15 seconds after the depression of a destination registering push button of the hall call register HCR at the specific floor. For example, the information requesting the stoppage at the fifth, seventh, eighth and ninth floors is stored in the temporary memory LAT when the call for the seventh floor is first registered and then, within l5 seconds thereafter, the calls for the eighth and ninth floors are registered in the hall call register I-ICRS disposed at the landing of the fifth floor.

Target floor memories RUNA, RUNB, RUNC and RUND are provided for the respective elevator cars A, B, C and D so that these elevator cars are stopped at the floors according to the contents of these memories. Coincidence detectors AA, AB, AC and AD are connected to the temporary memory LAT and to the respective target floor memories RUNA, RUNB, RUNC originating the hall call and the respective elevator cars A, B, C and D so that the elevator car nearest to the specific floor originating the hall call may desirably respond to the hall call.

The outputs of the coincidence detectors AA, AB, AC and AD and the outputs of the distance detectors SDA, SDB, SDC and SDD are applied to respective adders ANA, ANB, ANC and AND, and the results of ad dition are applied to an optimum elevator car selector MMD. The optimum elevator car selector MMD selects one of the elevator cars for which the coincidence between the contents of the temporary memory LAT and the contents of the target floor memories RUNA to RUND occurs in a greater number and which is relatively near the specific floor originating the hall call. Upon completion of the selection of the elevator car, a signal is applied to the calculating order control means CD from the optimum elevator car selector MMD, and the calculating order control means CD applies in turn a signal to gates G2A, G2B, G2C and 62D. The gates 62A to G2D are thereby opened so that the contents of the specific hall call register HCR are transferred to the target floor memory RUN for the selected elevator car.

When the selected elevator car stops at the specific floor originating the hall call, the call pertaining to this floor disappears but the remaining calls designating the other destination floors are left registered in the hall call register HCR disposed at the landing of this floor. A signal LD indicative of the arrival of the selected elevator car at this floor is applied to the gates G2A to 62D and the gates 62A to G2D are opened again so that the contents of the hall call register HCR disposed at the landing of this floor are transferred to the target floor memory RUN associated withthe selected elevator car. Information as to the floor numbers having been registered in the hall call register I-ICR until the selected elevator car arrives at the specific floor is also stored together with the previous information in the target floor memory RUN associated with the selected elevator car.

FIG. 5 is a circuit diagram showing the structure of one form of the calculating order control means CD preferably used in the control system. The calculating order control means CD includes a plurality of flipfiops FFl, FF2, FFll connected to a common OR element CR3 and to the hall call registers HCRI, I-ICR2, HCRll disposed at the landings of the 11 floors respectively. In FIG. 5, only three hall call registers I-ICRI, HCRZ and HCRI l and associated flip-flops FFl, FF2 and FFll corresponding to the first, second and I 1th floors are shown for the sake of simplicity.

FIG. 4 is a circuit diagram showing in detail the structure of the hall call register HCR. The hall call register HCR comprises a plurality of or I l destination registering push buttons I-IBl, BB2, I-IBll, a plurality of AND elements A], A2, All associated with the respective push buttons, an OR element 0R1 delivering an output when anyone of the AND elements is turned on, a NOT element N which is turned off in response to the appearance of an output from the OR element 0R3 in FIG. 5, that is, in response to the turn-off of anyone of the flip-flops FFl to FFll in FIG. 5, and an OR element CR2 and a delay element DI for applying another input to one of the AND elements A] to All with a preset delay time of, for example, 15 seconds in response to the depression of the push button associated with this AND element.

When, for example, a passenger standing at the eighth floor landing depresses the push button HB6 of the hall call register I-ICR8 as he wishes to be transferred to the sixth floor, two inputs among three inputs are applied to the associated AND element A6 (not shown), but this AND element A6 is not turned on because another input is not simultaneously applied thereto due to the interposition of the delay element D1 between it and the OR element 0R2. In a preset period of time of, for example, 15 seconds, an output appears from the delay element D1 and an output appears from the AND element A6. The OR element 0R1 is thereby turned on to apply a setting input S to the flipflop FF8 (not shown in FIG. 5) to set this flip-flop FF8. The output of the flip-flop FF8 is applied to the common OR element CR3, and the output of the OR element 0R3 is applied to the NOT element N which is thereby turned off to turn off all the AND elements Al to All. At the same time, the output of the OR element 0R3 is applied to a delay element D2, then to a delay element D3 so that calculating order command signals LS1 and LS2 are successivey delivered from the delay elements D2 and D3, respectively. The OR element 0R3 functions to lock any hall calls originating from the other floors while a suitable elevator car is being selected for responding to the hall call originated from a specific floor which is the eighth floor in this case. Thus, in response to the appearance of the output from the flip-flop FF8 (not shown) in FIG. 5, the OR element 0R3 is turned on to turn off all the NOT element N in the hall callregisters I-ICRl to I-ICRll in the manner described above. Upon completion of the calculation and selection of a suitable elevator car, the flipflops FFl to FFll are reset by the signal LS2.

FIG. 6 is a circuit diagram showing the structure of one form of the gate G1 preferably used in the control system. The gate G1 comprises a plurality of switches SWl to SW11 which are associated with the flip-flops FFl to FFll respectively. Thus, one of the switches SW1 to SW11 corresponding to the operating one of the flip-flops FFl ro FFll is closed. The output of the corresponding hall call register HCR is applied to the temporary memory LAT to be stored therein in response to the application of the signal LS1 from the calculating order control means CD.

FIG. 7 is a circuit diagram showing in detail the struc ture of the coincidence detectors AA to AD each of which includes a plurality of AND elements to which the temporary memory LAT and the corresponding target floor memory RUN apply their outputs. When, for example, the destination registering push buttons HB6, I-IB7 and HB8 of the hall call register HCR4 disposed at the fourth floor landing are depressed, the calls for the fourth, sixth, seventh and eighth floors are 7 registered in the temporary memory LAT as described already. Suppose, for example, that the elevator car A is instructed to stop at the sixth, seventh and eighth floors. In this case, the AND elements AA6, AA7 and AA8 (not shown) in the coincidence detector AA are in the on state. The output voltage E appearing across a resistor R in the coincidence detector AA is given by where r and r, (r r,,) are the resistances of the resistors R and R, respectively, N is the number of the AND elements which are in the on state, and the output from each AND element is taken as a unit voltage. Thus, the output voltage E is proportional to the number N of the AND elements which are in the on state, hence this voltage is representative of the number of coincidences between the floor numbers registered in the temporary memory LAT and the floor numbers stored already in the target floor memory RUNA for the elevator car A. The number of coincidences is similarly sought for the target floor memories RUNB, RUNC and RUND for the remaining elevator cars B, C and D.

In operation, suppose that the elevator cars A, B, c and D are located at the fourth, second, sixth and eighth floors respectively and the elevator cars A, B and D are moving upward while the elevator car C is moving downward as shown in FIG. 2. When a passenger standing at the sixth floor landing depresses the destination registering push button I-IB8 (FIGS. 1 and 4) of the hall call register HCR6 disposed at the sixth floor landing as he wishes to be transferred to the eighth floor, this destination registering push button is kept depressed and the hall call register HCR6 registers the calls for the sixth and eighth floors. As a result, two inputs are applied to the AND elements A6 and A8 (FIG. 4) in the hall call register HCR6 disposed at the sixth floor landing due to the fact that the NOT element N therein is in the on state since all the flip-flops FFl to FBI] are in the reset state. However, the AND elements A6 and A8 are not turned on because no output is yet delivered from the delay element D1. The depression of the designation registering push button applies two inputs to the OR element CR2, and thus the delay element D1 delivers its output in a preset period of time of, for example, 15 seconds. As a result, the AND elements A6 and A8 are turned on to turn on the OR element R1. The setting input S is applied to the flip-flop FF6 in the calculating order control means CD so as to set this flip-flop FF6. As soon as the flip-flop FF6 is turned on, the OR element 0R3 in FIG. 5 is turned on and the NOT element N in FIG. 4 is turned off to turn off the AND elements A6 and A8. It will be apparent from FIG. 5 that, in response to the appearance of an output from anyone of the flip-flops FFl to FFll in the calculating order control means CD, the common OR element 0R3 is turned on to deliver a signal for turning ofi the NOT elements N in all the hall call registers I-ICRl to HCRll. Thus, only one flip-flop among the l I flip-flops is turned on and kept in the on state due to the fact that such flip-flop has been turned on first due to the depression of the push button of the hall call register HCR disposed at the landing of the specific floor. That is, the flip-flops except the flip-flop FF6 corresponding to the sixth floor are in the ofi state. In this manner, a hall call originating from each floor is subjected to calculation for selecting a suitable elevator car.

In a period of time preset for the delay element D2, a signal LS1 appears from the delay element D2 to open the gate Gl. It will be seen from FIG. 6 that the hall call registers HCRI to HCRll are connected to the temporary memory LAT through the gate G1. Due to the fact that the flip-flop FF6 corresponding to the sixth floor is now set, the switch SW6 corresponding to the sixth floor is solely closed and the calls presently stored in the hall call register HCR6 are transferred to be registered in the temporary memory LAT in response to the application of the signal LS1 to the gate G1. If calls calling for the transfer to the seventh and ninth floors are originated by depressing the designation registering push buttons H87 and HB9 of the hall call register HCR6 within a period of time of about 15 seconds after the call calling for the transfer to the eighth floor was initially registered but before the signal LS1 appears, the calls calling for the stoppage at the sixth, seventh, eighth and ninth floors are registered in the temporary memory LAT.

The coincidence between the contents of the temporary memory LAT and the contents of the target floor memories RUNA, RUNB, RUNC and RUND for the respective elevator cars A, B, C and D is detected by the respective coincidence detectors AA, AB, AC and AD shown in FIG. 7. Suppose, for example, that the elevator cars A, B, C and D are initially instructed to stop at the seventh and eighth floors, at the seventh, eighth and ninth floors, at the fifth, fourth and third floors, and at the eighth, ninth and 10th floors respectively. Then, the number of coincidences is two in the case of the elevator car A, three in the case of the elevator car B, zero in the case of the elevator car C, and two in the case of the elevator car D. Therefore, the number of coincidences is greatest in the case of the elevator car B and this elevator car B is instructed to stop at the sixth floor when the operation of the distance detectors SDA, SDB, SDC and SDD is not taken into account.

However, if the specific elevator car thus selected on the basis of the greatest coincidence will require more time than the others in arriving at the specific floor, it is desirable that another suitable elevator car responds to such hall call. In order to deal with such a case, the present invention employs special means including the distance detectors SDA to SDD and the adders ANA to AND for compensating the number of coincidences for each elevator car by the period of time required for the elevator car to reach the specific floor.

In the running state of the elevator cars shown in FIG. 2', the periods of time T,,-6U, T 6U, T 6U and T -6U which are required for the respective elevator cars A, B, C and D to reach the sixth floor relate generally with the number of stoppages of the elevator cars until they reach the sixth floor and the physical distance between the elevator cars and the sixth floor. The distance detectors SDA, SDB, SDC and SDD detect the number of stoppages and the physical distance for the respective elevator cars A, B, C and D and apply compensating values to the adders ANA, ANB, ANC- and AND which add the compensating values to the signals representative of the numbers of coincidences applied from the respective coincidences applied from the respective coincidence detectors AA, AB, AC and AD. This compensating value is added in a polarity opposite to that of the signal representative of the number of coincidences, and therefore, the adder AN delivers a smaller output with the increase in the period of time required for the associated elevator car to reach the specific floor. In the above example, the number of coincidences in the case of the elevator car B is three, while that in the case of the elevator car A is two as described. Thus, when the compensating values applied from the distance detectors SDB and SDA are L2 and 0.] respectively, the adder ANA delivers an output which is larger than that of the adder ANB, and the elevator car A is selected to respond to the hall call originated from the sixth floor. More precisely, the optimum elevator car selector MMD selects the elevator car A and the calculating order control means CD delivers a signal LS2. As soon as the signal LS2 is delivered from the calculating order control means CD, the gates 62A to G2D are opened so that the floor number information stored in the hall call register HCR6 is transferred to the target floor memory RUNA. Since, in this case, the calls calling for the stoppage at the sixth, seventh, eighth and ninth floors have been registered in the hall call register HCR6, such information is added to the contents of the target floor memory RUNA for the elevator car A. The signal LS2 is applied to the flip-flops FFl to FFll in the calculating order control means CD shown in FIG. 5 to reset same with the result that all the hall call registers HCRl to HCRll are released from the locked state and one of the remaining elevator cars is selected so that it can respond to the hall call originating from another floor.

The elevator car A stops at the sixth floor according to the instructions of the target floor memory RUNA. When the elevator car A stops at the sixth floor, the information pertaining to the sixth floor registered in the hall call register HCR6 and the information pertaining to the sixth floor stored in the target floor memory RUNA are erased. The gates GZA to G2D are opened again and the contents of the hall call register HCR6 are transferred to the target floor memory RUNA. New information is added to the contents of the target floor memory RUNA and represents the floor numbers which have been registered in the hall call register HCR6 until the specific elevator car A reaches the spe' cific floor or sixth floor. (It is arranged so that, among the calls registered in the hall call register HCR, those originating from the floors lying in the direction opposite to the running direction of the elevator car are not transferred to the associated target floor memory.) Thus, when, for example, a call calling for the transfer to the tenth floor has been registered in the hall call register HCR6 before the specific elevator car A reaches the sixth floor, such information is added to the contents of the target floor memory RUNA upon arrival of the elevator car A at the sixth floor. Subsequently, all the calls registered in the hall call register ,HCR6 are reset. The elevator car A stopping at the sixth floor departs from such floor soon and successively stops at the seventh, eighth, ninth and 10th floors in order in this particular example.

What we claim is:

1. In an elevator control system for controlling a plurality of elevator cars servicing a plurality of service floor landings a service priority determining system comprising hall call originating means disposed at each floor landing for generating floor landing signals of designated floors so that passengers standing at the floor landing can designate the floors to which they want to be transferred, target floor memory means provided for each of said elevator cars for storing request signals pertaining to the floors at which each said elevator car has been instructed to stop, coincidence detecting means provided for each of said elevator cars for detecting the coincidence between the floor landing signals representing floor numbers designated by a hall call originating from one of the floors and the request signals representing floor numbers stored in said target floor memory means, and means for determining the priority order of operation of said elevator cars in response to said coincidence detecting means so that the elevator car for which the coincidence between floor landing signals and request signals occurs in a greater number can be preferentially selected to respond to the hall originating from such floor.

2. An elevator control system as claimed in claim 1, which comprises distance detecting means provided for each of said elevator cars for detecting the distance between the specific floor originating the hall call and each said elevator car, said means for determining the priority order of said elevator cars being responsive also to said distance detecting means so that priority is also determined on the basis of said distances thus detected.

3. An elevator control system as claimed in claim 1, which comprises distance detecting means provided for each of said elevator cars for detecting the actual distance to be run by each said elevator car until it reaches the specific floor originating the hall call taking the operating schedule of each said elevator car into account, said means for determining the priority order of said elevator cars being responsive also to said distance detecting means so that priority is also determined on the basis of the distances thus detected.

4. An elevator control system as claimed in claim 1, in which the floor numbers designated by the hall call originating from the specific floor and applied to said coincidence detecting means include also the floor numbers designated by an additional hall call originating from the same floor within a predetermined period of time.

5. An elevator control system as claimed in claim 3, which comprises means for counting time so that it starts its operation in response to the appearance of the first hall call and counts a predetermined period of time.

6. An elevator control system as claimed in claim 1, in which means are provided so that, upon completion of the selection of the elevator car for servicing the specific floor in response to the appearance of an output from said priority order determining means, said coincidence detecting means start their operation again for selecting an elevator car suitable for responding to a hall call originating from another floor.

* t i i