Patent GB-1172521-A (GB)
Title: Method and means for Controlling Elevator Cars
Inventor: GINGRICH JOHN ALVIN
IPC: B66B1/16
Filed: 1965-11-05
Abstract: 1,172,521. Lift control systems. DOVER CORP. (CANADA) Ltd. 3 Jan., 1967 [5 Nov., 1965], No. 47065/65. Heading B8L. A plurality of elevator cars are adapted to serve a plurality of floors, by continuously providing bits of information in binary digit form representing some or all of hall calls and car position and availability to answer the calls, repetitively scanning said bits of information in a predetermined order and sufficiently rapidly that the cars do not effectively change their positions during each scan, and dispatching the cars in response to the scanned information from wherever the cars happen to be. The system comprises counters and memory devices for each car, and means for supplying information to the circuits which determine the movement required. The hall call information comprises, for each floor, information as to up and down hall calls registered from that floor, and the car position and availability information may comprise, for each car, its availability to go up, its availability to go down, a car position corresponding to the nearest floor for which the car is available, and the degree of availability of the car. Moreover, the degree of availability of a car may be the number of hall calls that the car is arbitrarily allowed to answer without requiring assistance from other cars. The car calls and car loading are used to reduce the degree of availability of the car. Conveniently the hall call information as to down hall calls at the various floors and the car position and availability as to cars available to go down are scanned in ascending order from the lowest to the highest floor, and then the hall call information as to up hall calls and car position and availability information as to cars available to go up are scanned in descending order. Two consecutive bits of information may be used to indicate a car's degree of availability, one of them to indicate whether or not this car is available to answer two hall cars, and the other of them to indicate whether or not this car is available to answer one hall call, so that the combination of these consecutive bits can indicate that this car is available to answer none, one, two or three hall calls. Each car is not normally available to answer two hall calls, but is available to answer only one hall call if loaded beyond a predetermined load, or if an intervening car call would require this car to make two stops before being able to answer the second of two existing hall calls, and a car becomes unavailable if loaded beyond a higher predetermined load, or if two intervening car calls would require this car to make two stops before answering an existing hall call. It is determined whether there are hall calls above a car which the car should answer by resetting a counter at a point in the ascending scan during scanning of the conditions at the floor where the car is represented to be, and whether there are hall calls below a car which the car should answer by resetting a counter at a point in the descending scan. Thus when the up direction of travel is established for a car, and when there are no hall calls below it which it should answer, its counter may add one, instead of two, each time a car above with an availability of two is seen during the scan; and when the down direction of travel is established for a car, and when there are no hall calls above it which it should answer, its counter may add one, instead of two, each time a car below with an availability of two is seen during the scan. Conveniently the cars whose MG sets are running do not respond to the bits of information regarding the availability of cars whose MG sets are shut down automatically, and for each car whose MG set is automatically shut down it is determined when there are hall calls above it, which require it to start its MG set in order to answer some or all of these hall calls. The floors are divided into at least four groups of which the lowest group contains the main floor, and the cars are distributed throughout the building, when not otherwise required for the answering of car or hall calls, such that, as long as a predetermined number of cars more than one are available, in the absence of cars in the lowest group of floors the lowest car is brought down to the main floor, in the absence of cars in the upper two groups of floors the highest car travels up until it is at the lowest floor of the upper group of floors, in the absence of cars in any intermediate two immediately adjacent groups of floors, the lowest car in a group of floors above the two adjacent groups, provided that there are two or more such cars there, travels down until it is at the top floor of the lower of these two intermediate adjacent groups of floors, or, if there are less than two cars in the group of floors above the two adjacent groups, and there are no cars in the two intermediate adjacent groups of floors, the highest car in a group of floors below the two adjacent groups travels up until it is at the bottom floor of the higher of these two intermediate adjacent groups of floors, provided that there are at least two cars in the lowest group of floors. Alternatively the floors are divided into four groups of which the lowest group contains the main floor and the cars whose MG sets are running are distributed throughout the building, when not otherwise required for the answering of car or hall calls, such that, as long as two or more cars have their MG sets running, in the absence of cars with MG sets running in the lowest group of floors, the lowest car with MG set running is brought down to the main floor, in the absence of cars with MG sets running in the upper two groups of floors the highest car with MG set running travels up until it is at the lowest floor of the upper group of floors, in the absence of cars with MG sets running in the middle two groups of floors the lowest car with MG set running in the upper group of floors, provided that there are two or more such cars there, travels down until it is at the top floor at the lower of these two middle groups of floors, or, if there are less than two cars with MG sets running in the upper group of floors, and there are no cars with MG sets running in the middle two groups of floors, the highest car with MG set running in the lowest group of floors travels up until it is at the bottom floor of the higher of these two middle groups of floors, provided that there are at least two cars with MG sets running in the lowest group of floors. The order of registration of down hall calls, for floors above the main floor, may be continuously recorded, and during down peak, one group of cars may answer long-wait down hall calls and another group of cars answer other calls including up hall calls. Upon arrival at the main floor during down peak, cars may be allocated to said one group and remain in said one group only until they commence their next down trip, cars not so allocated and all cars in their down trip may belong to said other group. The allocation of cars to said one group or to said other group upon arrival at the main floor may follow a predetermined sequence independent of whether a car has previously been allocated to said one group. Conveniently the number of calls treated as long-wait calls equals the number of cars allocated to said one group.