Elevator system

An elevator system for a building having a plurality of floors, comprising:

• a plurality of elevator cars,
• means mounting said plurality of elevator cars for movement relative to the floors,
• up and down hall call registering means for registering calls for elevator service for up and down service directions, respectively, from at least certain of the floors,
• car call means associated with each of said elevator cars for registering car calls,
• assignment means assigning service directions from floors to said elevator cars according to a predetermined strategy,
• and clearing means periodically clearing the assignments of those service directions from the floors which do not have a registered hall call associated therewith,
• said assignment means reassigning said cleared assignments to said elevator cars according to the predetermined strategy,
• said assignment means including first means which assigns unassigned service directions from floors to each car related to the floors at which the car will stop due to registered car calls, and the direction in which the car will leave such floors, and second means responsive to the number of such car call related assignments given to a car for limiting the number of such assignments by said first means to N per car.

An elevator system for a building having a plurality of floors, comprising:

• a plurality of elevator cars mounted in the building to serve the floors therein,
• car call means associated with each of said elevator cars for making car calls,
• up and down hall call registering means for registering calls for elevator service for up and down service directions, respectively, from at least certain of the floors,
• supervisory control means assigning, clearing, and re-assigning service directions from the floors to said plurality of elevator cars according to a predetermined strategy,
• said supervisory control means including car call related means which assigns unassigned service directions ahead of each car associated with those floors at which each car will stop due to a registered car call, and limit means limiting such car call related assignments to the closest N stops ahead of each car to which the car is already committed.

An elevator system for a building having a plurality of floors, comprising:

• a plurality of elevator cars,
• means mounting said plurality of elevator cars for movement relative to the floors,
• up and down hall call registering means for registering calls for elevator service for up and down service directions, respectively, from at least certain of the floors,
• car call means associated with each of said cars for registering car calls,
• assignment means assigning service directions from floors to said elevator cars according to a predetermined strategy,
• and clearing means periodically clearing the assignments of those service directions from the floors which do not have a registered hall call associated therewith,
• said assignment means reassigning said cleared assignments to said elevator cars according to the predetermined strategy,
• said assignment means including first means which starts at the floor associated with the location of each car and proceeds in a predetermined direction therefrom, assigning only those unassigned service directions to each car which are related to the floors at which the car will stop due to registered car calls, and second means responsive to the sum of such car call related assignments and any pre-existing assignments to each car which are encountered as the car call related assignments are being made, to count the number of stops to be made by each car, with said second means limiting such car call related assignments to the N closest stops to be made by each elevator car.