US3831715A

US3831715A - Elevator control process and system

Info

Publication number: US3831715A
Application number: US00328677A
Authority: US
Inventors: H Matsuzawa; K Watanabe; I Inuzuka
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1972-02-02
Filing date: 1973-02-01
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: HK75876A; GB1420133A; DE2304716C3; CH555778A; DE2304716B2; CA969292A; DE2304716A1

Abstract

A process and system for controlling a plurality of elevator cars servicing a plurality of service floor landings in which at least three specific floors are selected beside the basic floor where the number of passengers is largest so that some of these elevator cars can stand by at the basic floor and one of the elevator cars can stand by at each of the specific floors. The up and down hall call responding zones of each elevator car are determined so that it can respond to up and down hall calls originating from the floor at which the elevator car is situated and from the floors lying between this elevator car and the nearest upper and lower elevator cars.

Description

United States Patent [191 Matsuzawa et a1.

[ ELEVATOR CONTROL PROCESS AND SYSTEM [75] Inventors: Hideto Matsuzawa; Kikuo Watanabe; 1520 Inuzuka, all of Katsuta, Japan [73] Assignee: Hitachi Ltd., Tokyo, Japan [22] Filed: Feb. 1, 1973 [21] App]. No.: 328,677

[30] Foreign Application Priority Data [11] 3,831,715 [45] Aug. 27, 1974 3,378,107 4/1968 Madison 187/29 3,412,826 11/1968 Glaser 3,511,343 5/1970 Lamater 187/29 [57] ABSTRACT A process and system for controlling a plurality of elevator cars servicing a plurality of service floor landings in which at least three specific floors are selected beside the basic floor where the number of passengers is largest so that some of these elevator cars can stand by at the basic floor and one of the elevator cars can stand by at each of the specific floors. The up and down hall call responding zones of each elevator car are determined so that it can respond to up and down hall calls originating from the floor at which the elevator car is situated and from the floors lying between this elevator car and the nearest upper and lower ele-' vator cars.

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ELEVATOR CONTROL PROCESS AND SYSTEM This invention relates to improvements in the process and system for controlling the operation of an elevator car group consisting of a plurality of elevator cars disposed for parallel operation in a building.

In a building in which a plurality of elevator cars are arranged for parallel operation under control of group control means, various operation modes are commonly prepared to deal with the traffic. For example, when the traffic is busy, the individual elevator cars are operated in a substantially uniformly dispersed condition within the overall service range, while when the traffic I is idle, all the elevator cars are controlled so that they stand by at a basic floor and start to move only when calls are originated. Various other operation modes are presently employed. Suppose, for example, that a hall call is originated from one of upper floors of a multifloor building in a condition in which the traffic is idle. Since one of the elevator cars standing by at the basic floor responds substantially to the hall call in such a case, the passenger standing at the service floor landing of the upper floor must wait anxiously for the elevator car departing the basic floor and moving upward toward the floor through many intermediate floors.

It is an object of the present invention to provide a process and system for controlling the operation of a plurality of elevator cars servicing a plurality of service floor landings in such a manner that these elevator cars can be suitably dispersed to stand by at different floors thereby reducing the waiting time for passengers and realizing an efficient parallel operation of the elevator car group.

Another object of the present invention is to provide a process and system for controlling a plurality of elevator cars in such a manner that, even when the number of operatable elevator cars is decreased, the remaining operatable elevator cars can be suitably dispersed to stand by at different floors.

A further object of the present invention is to provide a process and system for controlling a plurality of elevator cars in which means are provided so that, even when the preset dispersed stand-by mode islost due to the operation of one or some of the elevator cars, the dispersed stand-by instructions for the unsuitable ele-' vator cars can be cancelled and other suitable elevator cars can be selected to stand by at the predetermined floors.

One of the features of the present invention resides in the fact that a plurality of elevator cars are suitably dispersed to stand by at at least three specific floors including a basic floor and each elevator car responds to up hall calls originating from the floors ranging from the floor one floor position below the floor position of the nearest upper elevator car to the floor at which the specific elevator car is situated and to down hall calls originating from the floors ranging from the floor one floor position above the floor position of the nearest lower elevator car to the floor at which the specific elevator car is situated.

Another feature of the present invention resides in the fact that, in the system having the above feature, one or more elevator cars dispersed to stand by at their specific floors except the basic floor are returned to the basic floor when the number of operatable elevator cars is decreased to such an extent that it is no more possible to secure all the elevator cars previously scheduled to stand by at the specific floors and at the basic floor. 7

A further feature of the present invention resides in the fact that a plurality of stand-by zones each consist- FIG. 1 shows the manner of operation of elevator.

cars in response to hall calls in a known system in which such elevator cars are dispersed to stand by at a plurality of floors;

FIG. 2 shows the basic stand-by mode and hall call responding zones of individual'elevator cars dispersed to stand by at different floors according to the present invention;

FIG. 3 shows one form of the change in the hall call responding zones of the individual elevator cars from the basic stand-by mode shown in FIG. 2 inresponse to a hall call;

FIG. 4 shows another form of the change in the hall call responding zones of the individual elevator cars according to the present invention;

FIG. 5 shows a further formof the change in the hall call responding zones of the individual elevator cars according to the present invention;

FIG. 6 shows one form of cancellation and transfer of the dispersed stand-by instructions according to the present invention;

FIG. 7 shows another form of cancellation and transfer of the dispersed stand-by instructions according to the present invention;

FIG. 8 shows the stand-by mode and service zones of the dispersed elevator cars when the number of opertable elevator cars is five;

FIG. 9 shows the stand-by mode and hall call responding zones of the dispersed elevator cars when the number of operatable elevator cars is four;

FIG. 10 shows the stand-by mode and hall call responding zones of the dispersed elevator cars when the number of operatable elevator cars is three;

FIG. 1 1 shows the structure of a circuit for detecting the number of operatable elevator cars in the system according to the present invention;

FIG. 12 shows the structure of a position detecting circuit provided for each elevator car in the system according to the present invention;

FIG. 13 shows the structure of a dispersed stand-by instruction circuit in the system according to the present invention;

FIG. 14 shows the structure of an auxiliary dispersed stand-by instruction circuit in the system according to the present invention;

FIG. 15 shows the structure of a service zone instruction circuit provided for each elevator car in the system according to the present invention; and

FIG. 16 shows the structure of a position detecting circuit for detecting the position of all the elevator cars in the system according to the present invention.

An elevator control method as described below has been proposed in an effort to obviate the drawbacks described previously. According to the proposed control method, the entire service range of a plurality of elevator cars arranged for parallel operation in a building is divided into a plurality of zones and these elevator cars are dispersed to stand by in the respective zones. The number of floors included in each zone is generally selected to be four to six although it varies depending on the structure of the building and operating conditions of the elevator cars. The elevator car standing by in each zone responds to hall calls originating from the floors belonging to that zone.

FIG. 1 shows by way of example the manner of dispersion of elevator cars according to the known process. Referring to FIG. 1, six elevator cars A to F are provided for servicing seven service floor landings in a building having seven floors and the seven floors are divided into three zones Z1, Z2 and Z3, the first zone Z1 including the first and second floors, second zone Z2 including the third, fourth and fifth floors, and third zone Z3 including the sixth and seventh floors. Suppose that the traffic is idle and the elevator cars A, B, C and F are standing by at the basic floor or first floor in the zone Z1, while the elevator cars D and E are standing by in the respective zones Z2 and Z3 as shown. The elevator cars D and E standing by in the second and third zones Z2 and Z3 may be at rest at one of floors in the zones depending on the previous operating conditions. Suppose, for example, that the elevator cars D and E stand by at the third and sixth floors respectively. Thus, when a down call is originated from the fifth floor, the elevator D responds to such call because it is standing by in the zone Z2. However, due to the fact that the elevator car D is situated at the third floor which is the lowest floor of the zone Z2, the elevator car D must move upward to the fifth floor, and after taking a passenger therein, reverses its moving direction as shown by the arrow to move downward to the destination floor registered in the cage by the passenger.

Such manner of operation will be compared with the case in which the elevator car E standing by in the zone Z3 responds to the down call originating from the fifth floor and moves downward in a direction as shown by the arrow b. In the illustrated situation, the latter manner of operation is remarkably advantageous over the former manner of operation although we cannot simply conclude so in view of the problem of later zoning. Further, an up call may then be originated from the fourth or fifth floor. In such a case, the former manner of operation is inefficient in that the elevator car D which has moved downward in response to the down call from the fifth floor in the direction shown by the arrow a must move upward again to respond to the up call originating from the fourth or fifth floor. In contrast. the latter manner of operation is remarkably efficient in that the elevator car D can move upward to respond to the up call originating from the fourth or fifth floor even after the elevator car E responding to the down call originating from the fifth floor has move downward in the direction shown by the arrowb. However, the latter manner of operation is merely imaginary and cannot be put into practical use due to the fact that it ignores the significance of zoning.

In the present invention, at least three specific floors are selected as floors at which elevator cars are dispersed to stand by. More precisely, the first floor which may be the basic floor, third floor, fifth floor and seventh floor are selected as specific floors as shown in arranged to respond to up calls originating from the floors ranging from the floor one floor position below the floor position of the nearest upper elevator car to the floor at which the specific elevator car is situated and to down calls originating from the floors ranging from the floor one floor position above the floor position of the nearest lower elevator car to the floor at which the specific elevator car is situated. In the case of, for example, the elevator car C standing by at the third floor as shown in FIG. 2, the up and down hall call responding zones of this elevator car are determined so that it responds to up calls originating from the up hall call responding zone, i.e., from the floors ranging from the fourth floorone floor position below the fifth floor at which the nearest upper elevator car B stands by to the third floor at which it is situated and to down calls originating from the down hall call responding zone, i.e., from the floors ranging from the second floor one floor position above the first floor at which the nearest lower elevator car D stands by to the third floor at which it is situated. The call responding zones of the individual elevator cars are shown by the arrows in FIG.

2 and are tabulated below.

The arrangement of the elevator cars and determination of the call responding zones in this manner eliminates inefficient operation as previously described and ensures quite efficient operation of the elevator cars for calls originating from all the floors. 1

In the present invention, when the moving direction of any one of the elevator cars is determined, one of its up'and down call responding zones from which calls in the direction opposite to the moving direction of the elevator car may originate is cancelled and one of the down and up call responding zones of the nearest upper or lower elevator car situated forward of this specific elevator car to be moved is extended to cover the cancelled call responding zone portion.

The call responding zone so extended of the nearest elevator car is clearly such as originating calls in the direction opposite to the moving direction of the firstmentioned specific car.

This change in the call responding zones will be described with reference to FIG. 3. Suppose, for example, that a down call shown by the symbol V is originated from the fifth floor and the elevator car B responding to such call starts to move downward. In such a case, the up call responding zone from which backward calls for the elevator car B, that is, in this ease, up calls from the fifth and sixth floors may originate are cancelled, and the up call responding zone of the nearest lower elevator car C situated forward of or below the elevator car B is extended as shown. In FIG. 3, the elevator car 8 cannot respond to upcalls from the fifth and sixth floors which have been included in the call responding zone of the elevator car B, due to the fact that the direction of movement of the elevator car B is decided to In the present invention, furthermore, when any one of the elevator cars, after its moving direction has been determined and the one responding zone of the forwardly situated nearest elevator car has been extended to cover the cancelled zone of the moving elevator car, as described above in connection with FIG. 2, begins to move to another floor, one of the down and up call responding zones from which calls in the direction opposite to the moving direction of the elevator car may originate and at least a part of the other zone are cancelled and the down or up call responding zone of the nearest lower or upper elevator car situated backward of this moving specific elevator car is extended to cover the cancelled part of the other zone. The call responding zone so extended of the nearest elevator car is clearly such as originating calls in the moving direction.

This change in the call responding zones will be described with reference to FIG. 4. Referring to FIG. 4, the elevator car B responding to-the down call from the fifth floor has started its downward movement. In such a case, the backward call for the elevator car B, that is, in this case down call from the fifth floor is cancelled and the down call responding zone of the nearest upper elevator car A situated backward of or above the elevator car B is extended as shown. In FIG. 4, the door of the elevator car B has been closed at the fifth floor landing and the elevator car B has started its downward movement. Since this elevator car B cannot respond to a down call originating later from the fifth floor, the down call responding zone of the elevator car A is extended to cover such a hall call. In the illustrated example, the elevator cars are dispersed to stand by at the four specific floors including the basic floor in the seven-storied building, and thus, the distance between these specific floors is short or corresponds to the spacing between two floor levels. However, in an actual elevator system, the number of floors is large and there is a greater spacing between these specific floors. Therefore, the elevator car B moving downward from one of the specific floors toward the nearest lower specific floor must pass a plurality of intermediate floors and the call responding zOne is changed as this elevator car passes through these intermediate floors.

It will thus be understood that, whenever one of the elevator cars is rendered incapable of responding to hall calls originating from its call responding zones due to movement in either direction, the call responding zones of another most convenient elevator car are extended. Therefore, whenever one of the elevator cars is rendered incapable of responding to hall calls for any other reasons than the positional reason, the call responding zones of other most convenient elevator cars should be similarly extended. When, for example, the elevator car C in FIG. 2 is loaded to its full capacity, the up call responding zone of the elevator car D is extended to cover up calls from the first to fourth floor, and the down call responding zone of the elevator car B is extended to cover down calls from the secondand third floors, while the elevator car C is operated depending on the cage call registered by the passenger in the cage. I

FIG. 5 shows the state in which the elevator car B having moved downward from the fifth floor as shown in FIG. 4 is at rest at the fourth floor and the elevator car D has moved upward to the fifth floor. 'It is needless to say that the elevator cars should be controlled to have the up and down call responding zones most suitable for their positions in spite of whatever changes in the relative positions of the elevator cars. To this end, arrangement is made so that each elevator car can respond to up calls originating from an up hall call responding zone consisting of the floors ranging from the floor one floor position below the floor position of the nearest upper elevator car to the floor at which the specific elevator car is situated and to down calls originating from a down hall call responding zone consisting of the floors ranging from the floor one floor position above the floor position of the nearest lower elevator car to the floor at which the specific elevator car is situated, irrespective of whatever changes in the relative positions of the elevator cars. Thus, according to the present invention, the call responding zones of the elevator cars are changed in a manner as shown by the thin solid lines in FIG. 5 and these new call responding zones are tabulated as follows:

These call responding zones change successively with the operation of the elevator cars so that they can be continuously maintained most suitable for the situation. A problem arises as to whether the first dispatching instructions should be applied to the elevator car E or F standing by at the basic floor when a situation as shown in FIG. 5 occurs. However, any description as to such a case is not given herein as it has not any direct concern with the present invention.

In the foregoing description, the term floor at which an elevator car is situated is usedto indicate such specific floor that an elevator car is situated at a position at which is can respond to a hall call originating from the specific floor. For example, even when the position of an elevator car is very close to the third floor, this elevator car is considered to be situated at the fourth floor when this elevator car has already passed through the third floor during its upward movement or when this elevator car is moving at a high speed and cannot stop at the third floor although its position is between the second and third floors.

Further. the terms nearest upper elevator car and nearest lower elevator car" are used to denote such' elevator cars which are situated at the nearest upper and lower positions respectively relative to a specific elevator car (an elevator car under consideration). In the case of the elevator car C in FIG. 5, no elevator cars are present below it due to the fact that the elevator cars E and F are cut off from the power supply and are not ready to operate. In such a case, the searching direction is reversed and the elevator car B at rest at the fourth floor is the nearest lower elevator car relative to the elevator car C.'The nearest upper elevator should be similarly understood.

The number of specific floors in the present invention is at least three as described already and it is desirable that these specific floors include the basic floor. The term basic floor denotes generally the first floor at which the number of passengers is largest and a plurality of elevator cars can stand by thereat. In the present invention, however, the basic floor which is one of the specific floors is not necessarily the floor at which the number of passengers is largest, and any other suitable fioor near such floor may be selected.

'The foregoing description has referred to an improved stand-by system and determination of the call responding zones. However, this stand-by mode is not fixed at all and is flexible. Thus, when one of the elevator cars has moved to an unsuitable position, the dispersed stand-by instructions for this elevator car are cancelled and transferred to another suitable elevator car.

The elevator car, for example, the elevator car B in FIG. 4 is not situated at the fifth floor and it is considered to be situated at the fourth floor as described hereinabove. In this situation, no elevator car stands by at the intermediate specific floor or fifth floor although the elevator cars A and C stand by at the upper specific floor or seventh floor and lower specific floor or third floor respectively. In such a case, it is not preferable to readily apply the dispersed stand-by instructions to another elevator car. The elevator car B leaving the fifth floor may stop at the fourth floor, and after getting off of the passenger, its operation may be ended. In this case, the operation efficiency is higher when the elevator car B is moved upward to the fifth floor again than when another elevator car is instructed to move to the fifth floor. The same applies to any other elevator cars standing by at the specific floors.

As described previously, it is one of the objects of the present invention to provide. in a system in which a plurality of elevator cars are dispersed to stand by at at least three specific floors, means for cancelling the dis persed stand-by instructions for one of the elevator cars and transferring such instructions to another suitable elevator car. The cancellation of the dispersed stand-by instructions for one of the elevator cars and transfer of such instructions to another suitable elevator car, which is one of the'features of the present invention, will be described with reference to FIG. 6.

Referring to FIG. 6, a stand-by zone Z3 is established and consists of aplurality of continuous floors, that is, the floors ranging from the second to the fourth floor including the lower specific floor or third floor. The dispersed stand-by instructions for the elevator car C standing by at the lower specific floor are not cancelled unless the elevator car C moves out of the stand-by zone Z3 consisting of the second, third and fourth floors. Therefore, upon completion of the service for any call originating from the floor in the stand-by zone Z3, the elevator car C is returned to the third floor again to stand by at this floor. On the other hand, when the elevator car C moves out of the stand-by zone Z3 in response to a call, the dispersed stand-by instructions for the elevator car C are cancelled. In this latter case, the operation efficiency will be improved when the instructions are applied to another suitable elevator car. After the elevator car C has moved out of the stand-by zone Z3, the instructions must be applied to another most suitable elevator car so that it is moved to and stand by at the lower specific floor. To this end, searching operation is carried out to find any elevator car which exists within this stand-by zone Z3 and is ready to move toward the third floor. If such elevator car is found in the zone Z3, it is desirable to apply the instructions thereto. If such elevator car is not found in this stand-by zone Z3, the instructions may be applied to the elevator car E standing by at the basic floor so as to move same to the third floor. This manner of zoning can easily realize the desired cancellation and transfer of the dispersed stand-by instructions. However, the

above manner of operation will eventually result in a' situation in which no elevator cars stand by at the basic floor if the remaining elevator car F may move upward for carrying passengers to the upper floors or in response to the application of the dispersed stand-by instructions.

Generally, the demand for elevator cars in a building is such that the demand for transfer from the basic floor I toward the other floors can be considered to be substantially equal to the demand for transfer between the intermediate floors exceptthe basic floor. Therefore, at least one elevator car should always stand by at the basic floor. It is therefore desirable to bring back at least one of the dispersed elevator cars to the basic floor when the number of elevator cars standing by at the basic fioor is reduced to a predetermined number which may be zero or one. Further, in an idle traffic condition, the power supply for the MG set or motor of the elevator cars standing by at the basic floor or any other specific floors is commonly stopped in a predetermined period of time after they are brought to the position to stand by at such position. The return of the inactive elevator car standing by at one of the specific floors requires energization of the M-G set thereof. Therefore, the elevator car in which the M-G set is in the energized state should only be brought to the basic floor. Further, in the case in which the elevator car or cars standing by at the basic floor are inactive due to the deenergization their M-G set, the dispersed standby instructions should not be cancelled even when the elevator cars dispersed in the respective stand-by zones may move out of such zones. "15" In the dispersed stand-by mode of the character above described, incapability of operation of one or some of the elevator cars due to, for example, maintenance and inspection, trouble, or emergency would lead to insufficient service of the entire elevator system, and some measures must be taken to deal with such a situation. Therefore, when the number of operatable elevator cars is decreased for some reasons, the dispersed stand-by mode must be suitably modified so as not to deteriorate the service for passengers.

This will be described with reference to FIG. 2 by way of example. When any one of the elevator cars is rendered inoperative, the elevator system is controlled so to establish an operation mode in which as it were the elevator car E or F is eliminated in FIG. 2. By this manner of control, the desired satisfactory service can be realized except the case in which the number of pas-' sengers waiting at the basic floor landing is unusually large. FIG. 8 shows the state in which the elevator car E or F is eliminated from the arrangement shown in FIG. 2.

When two of the elevatorcars are rendered inoperative, the elevator car standing by at the lower specifc floor (elevator car C in FIG. 2)-is eliminated in addition to the elevator car E or F and the call responding zones of the remaining elevator cars are changed as seen in FIG. 9. When three of the'elevator cars are rendered inoperative, the elevator car standing by at the intermediate specific floor (elevator car B in FIG. 2) is similarly additionally eliminated. The result is shown in FIG. 10.

Generally, the demand for elevator cars in a building is such that the demand for transfer from the basic floor (lobby floor) toward the other floors can be considered to be substantially equal to the demand fortransfer between the intermediatefloors excep the basic floor. It is therefore desirable to have a plurality of elevator cars standing by at the basic floor at whatever conditions. On the other hand, the purpose of the dispersed standby system is to shorten the waiting time for whatever hall calls. Thus, an excessively large lower limit of the number of elevator cars which should stand by at the basic floor is undesirable in that the service for hall calls originating from the intermediate floors will be deteriorated when the number of operatable elevator cars is decreased. In view of the above problem, the lower limit of the number of elevator cars standing by at the basic floor should be carefully selected to give the best result. In an application of the present invention to a group control system for controlling a group of elevator cars less than ten, a good result could be obtained when the lower limit of the number of elevator cars standing by at the basic floor was set at two.

In a group control system for controlling a group of six elevator cars as shown in FIG. 2, the setting of the lower limit of the number of elevator cars standing by at the basic floor becomes effective when two out of the six elevator cars are rendered inoperative, and the elevator car standing by at the lower specific floor nearest to the basic floor is eliminated. This results in the service mode shown in FIG. 9 and the two contradictory demands above described can thereby be satisfied in the most appropriate form. A situation in which more than two elevator cars are rendered inoperative simultaneously would not occur as a matter of fact. If such a situation would .occur, the dispersed stand-by mode may be modified in a manner as shown in FIG. 10.

An embodiment of the system according to the present invention will now be described with reference to FIGS. 11 to 16. For simplicity of description, it is assumed that an elevator car bank consisting of six elevator cars A, B, C, D, E and F is provided in a sevenstoried building for servicing the service fioor landings of the first floor (bottom terminal) to the seventh floor. Although the basement and rooftop are not taken into consideration, they may be included in the service range of the elevator cars. Further, although no description is given herein as toan elevator system having express zones, the present invention is also applicable to such elevator system. FUrthermore, the present invention can be applied to any other elevator systems of different arrangement.

There are two traffic modes, that is, an idle traffic mode in which the traffic is not heavy or is idle in the day and a busy" traffic mode in which the traffic is relatively heavy or busy during the remaining period of time of the day. The number of specific floors at which the elevator cars are initially dispersed to stand by is suitably determined depending on the number of elevator cars, number of service floor landings, presence or absence of express zones, and peculiarity of the floors (for example, heavy traffic due to presence of offices of the top management of a firm). However, description will be given herein as to the case in which the ate specific floor or fifth floor and lower specific floor or third floor, and the remaining three elevator cars stand by at the bottom terminal.

Before giving detailed description of the system, the name and function of various relays will be described. Those relays and contacts bearing the suffixes A, B, C, D, E and F in FIGS. 11 to 16 are provided for the respective elevator cars A, B, C, D, E and F, while those relays and contacts not bearing the suffixes A, B, C, D, E and F are common to all the elevator cars A, B, C, D, E and F. For simplicity of description, the relays and contacts associated with the elevator car A will solely be described. Further, for simplicity of illustration, the circuits associated with the elevator cars A and F and with the first and seventh floors are solely illustrated, and those associated with the elevator cars B to E and with the intermediate floors are shown by dotted lines or omitted, but it is apparent that similar circuits are provided for the latter.

10A Operatable condition relay This relay is energized when the elevator car A is capable of controlled operation. This relay is deenergized when the elevator car A is not capable of controlled operation due to, for example, trouble, maintenance and inspection, emergency or shutdown. 41A 47A Position detection relays The less significant digit of the numeral designates the floor number, and the elevator car position is detected by the leading contactor on the elevator car. When the elevator car A is at rest at one of the floors, the position detection relay corresponding to such floor is energized, while when the elevator car A is moving, the position detection relay corresponding to the nearest floor at which the moving elevator car A can be stopped is energized. Therefore, this position varies depending on the actual physical position of the car and the moving speed of the car. For example, the position detection relay 44A is energized when the elevator car A is at rest at the fourth floor. However, when the elevator car A is moving upward past the fourth floor, the position detection relays 45A, 46A and 47A are energized when the speed of the elevator car A is low, intermediate and high respectively. Further, the energization and deenergization of these position detection relays takes place necessarily with a suitable overlap. For example, the position detection relay 44A is deenergized after energization of the position detection realy 45A when the elevator car A is moving upward toward the fifth floor from the fourth floor. 53A Lower specific floor relay This relay is energized when anyone of the position detection relays 42A, 43A and 44A is energized. 55A Intermediate specific floor relay This relay is energized when any one of the position detection relays 44A, 45A and 46A is elergized. 57A Upper specific floor relay This relay is energized when any one of the position detection relays 46A and 47A is energized. 53TA Lower specific floor timing relay This relay is energized in delayed relation in response to the energization of the lower specific floor relay 53A and is deenergized in delayed relation in response to the deenergization of the lower specific floor relay 53A. 55TA Intermediate specific floor timing relay This relay is energized in delayed relation in response to the energization of the intermediate specific floor relay 55A and is denergized in delayed relation in response to the denergization of the intermediate specific floor relay 55A. 57TA Upper specific floor timing relay This relay is energized in delayed relation in response to the energization of the upper specific floor relay 57A and is deenergized in delayed relation in response to the deenergization of the upper specific floor relay 57A. 11A Upward movement relay This relay is energized during upward movement of the elevator car A. 12A Downward movement relay This relay is energized during downward movement of the elevator car A 13A Deceleration position relay This relay is energized when the elevator car A in motion reaches the decelerating position for each floor, and this decelerating position is determined by the moving speed of the elevator car A. 14A Full load detection relay This relay is energized when the elevator car A is loaded to its full capacity. 15A Stop relay The elevator car A is decelerated to stop when this relay is energized. 16A M-G relay This relay is energized during operation of the M-G set of the elevator car A. 21A Upward movement selection relay Upward movement is instructed when this relay is energized. 7 22A Downward movement selection relay Downward movement is instructed when this relay is energized. 23A Stopping floor up call detection relay This relay is energized when an up hall call is originated from the floor toward which the elevator car A is moving under deceleration or at which the car A is at rest. 24A Stopping floor down call detection relay This relay is energized when a down call is originated from the floor toward which the elevator car A is moving under decleration or at which the car A is at rest. 31A Upward movement instruction relay This relay is energized when the elevator car A is previously instructed for upward movement. 32A Downward movement instruction relay This relay is energized when the elevator car A is previously instructed for downward movement. lCA 7CA Cage call relays These relays are energized when cage calls are registered. The numeral represents the floor number. 70A First dispatch relay This relay is energized when the elevator car A stands by at the basic floor and is designated as a first dispatching car. 63A Lower specific floor stand-by relay When this relay is energized, the elevator car A stands by at the lower specific floor to operate in the call responding zone including the third floor.

65A Intermediate specific floor stand-by relay When this relay is energized, the elevator car A stands by at the intermediate specific floor to operate in the call responding zone including the fifth floor. 67A Upper specific floor stand-by relay When this relay is energized, the elevator car A stands by at the upper specific floor to operate in the call responding zone including the seventh floor. 69A Stand-by relay This relay is energized when the elevator car A is instructed to stand by at anyone of the upper, intermediate and lower specific floors and is deenergized with predetermined delay time when the instructions are cancelled. 10H Three car operation relay This relay is energized when three out of the six elevator cars are capable of controlled operation. 10M Four car operation relay This relay is energized when four out of the six elevator cars are capable of controlled operation. 10L Five car operation relay This relay is energized when five out of the six elevator cars are capable of controlled operation. 41UP 46UP Common position relays (up) These relays are common to all the elevator cars and the less significant digit of the numeral represents the floor number. These relays are energized by the position relay of the elevator cars which are not instructed for downward movement. 42DN 47DN Common position relays (down) These relays are common to all the elevator cars and the less significant digit of the numeral represents the floor number. These relays are energized by the position relay of the elevator cars which are not in-. structed for upward movement. lUP-6UP Up hall call relays These relays are energized when up hall calls are registered. The numeral represents the floor number. 2DN-7DN Down hall call relays These relays are energized when down hall calls are registered. The numeral represents the floor number. 41? Lobby stand-by relay This relay is energized when anyone of the elevator cars stands by at the basic floor.

Claims

1. A process for controlling a plurality of elevator cars servicing a plurality of service floor landings comprising selecting at least three specific floors among all the floors and suitably dispersing said elevator cars to stand by at said specific floors so that each of said dispersed elevator cars can respond to up hall calls originating from an up hall call responding zone consisting of the floors ranging from the floor one floor position below the floor position of the nearest upper elevator car to the floor at which said specific elevator car is situated and to down hall calls originating from a down hall call responding zone consisting of the floors ranging from the floor one floor position above the floor position of the nearest lower elevator car to the floor at which said specific elevator car is situated.

2. An elevator control process as claimed in claim 1, wherein when the direction of movement of an elevator car is determined, one of said hall call responding zones of said elevator car from which zone, hall calls in the direction opposite to said direction of movement of said car originate is cancelled, and one of hall call responding zones of another elevator car nearest to the first-mentioned elevator car in said direction of movement of the first-mentioned elevator car is extended to cover said cancelled hall call responding zone, hall calls originating from said one of hall call responding zones of said other elevator car being in the direction opposite to the direction of movement of the first-mentioned elevator car.

3. An elevator control process as claimed in claim 2, wherein when an elevator car is moving from its original floor position to another floor position in said direction of movement, at least a part of the other hall call responding zone of said elevator car from which zone, hall calls in said direction of movement originate is further cancelled, and one of hall call responding zones of another elevator car nearest to the first-mentionEd elevator car in the direction opposite to said direction of movement of the first-mentioned elevator car is extended to cover said cancelled part of said other hall call responding zone, hall calls originating from said one of hall call responding zones of said other elevator car being in the direction of movement of the first-mentioned elevator car.

4. An elevator control process as claimed in claim 1, wherein when an elevator car is loaded with more than a predetermined load, the up hall call responding zone and the down hall call responding zone of said elevator car are cancelled, and the hall call responding zones of the nearest upper and lower elevator cars relative to said elevator car are extended to cover said cancelled hall call responding zones.

5. A process for controlling a plurality of elevator cars servicing a plurality of service floor landings comprising suitably dispersing said elevator cars so that each of said elevator cars can respond to up hall calls originating from an up hall call responding zone consisting of the floors ranging from the floor one floor position below the floor position of the nearest upper elevator car to the floor at which said specific elevator car is situated and to down hall calls originating from a down hall call responding zone consisting of the floors ranging from the floor one floor position above the floor position of the nearest lower elevator car to the floor at which said specific elevator car is situated, irrespective of any variations in the relative positions of the individual elevator cars.

6. An elevator control process as claimed in claim 1, wherein said at least three specific floors include the basic floor at which elevator cars should always stand by.

7. An elevator control process as claimed in claim 1, wherein the floor at which the number of passengers is largest is selected to be one of said at least three specific floors.

8. An elevator control process as claimed in claim 1, wherein the floor at which the number of passengers is the largest is selected to be one of said at least three specific floors, and said selected floor is the basic floor at which elevator cars should always stand by.

9. An elevator control process as claimed in claim 6, wherein when the number of operatable elevator cars is decreased to such an extent that it is no more possible to secure all the elevator cars previously scheduled to stand by at said specific floors and at said basic floor, the number of said specific floors is decreased to the same extent.

10. An elevator control process as claimed in claim 9, wherein at least one of said selected specific floors nearer to said basic floor than the other specific floors is returned to be a usual floor at which no elevator car stands by.

11. An elevator control system for controlling a plurality of elevator cars servicing a plurality of service floor landings comprising means for selecting at least three specific floors among all the floors for dispersing said elevator cars to said specific floors, means establishing a plurality of stand-by zones each consisting of predetermined successive floors including one of said specific floors, means for detecting the position and moving direction of the individual elevator cars, means for selecting elevator cars as dispersed stand-by cars at said specific floors in response to the outputs of said stand-by zone establishing means and said position and moving direction detecting means, means for instructing the selected cars to stand by at said specific floors, and means for causing said dispersed stand-by cars to stop at said individual specific floors instructed by said stand-by instruction means.

12. An elevator control system as claimed in claim 11, wherein said stand-by instruction means includes means for cancelling the stand-by instructions for an elevator car standing by at its originally associated specific floor when said elevator car moves out of said standby zone.

13. An elevator control system as claimEd in claim 11, wherein said stand-by instruction means includes means for applying the stand-by instructions to an elevator car which is present in a stand-by zone including one of said specific floors to which said elevator car was not originally dispersed and tends to move toward said specific floor.

14. An elevator control system as claimed in claim 11, wherein said stand-by instruction means includes means for applying the stand-by instructions to one of a plurality of said elevator cars standing by at the basic floor at which such elevator cars should always stand by among said specific floors, when any elevator car tending to move toward one of said specific floors except said basic floor is not present in the zone including said specific floor.

15. An elevator control system as claimed in claim 12, wherein said at least three specific floors include the basic floor at which elevator cars should always stand by, and means is provided for cutting off the output of said stand-by instruction cancelling means when none of said elevator cars standing by at said basic floor have their motors energized.

16. An elevator control system as claimed in claim 11, wherein said at least three specific floors include the basic floor at which elevator cars should always stand by, and means is provided for applying the basic floor returning instructions to an elevator car standing by at its specific floor with the motor thereof energized, when a predetermined number of elevator cars are not standing by at said basic floor.