Available car elevator control including means to provide extension floor service

Claim 1

IN AN ELEVATOR SYSTEM FOR A STRUCTURE HAVING A PLURALITY OF VERTICALLY-SPACED FLOORS INCLUDING A MAIN FLOOR, A PLURALITY OF INTERMEDIATE FLOORS ABOVE THE MAIN FLOOR AND AN EXTENSION FLOOR BELOW TH MAIN FLOOR, A PLURALITY OF ELEVATOR CARS, DOOR MEANS FOR EACH OF THE ELEVATOR CARS OPERABLE FOR OPENING AND CLOSING A DOORWAY OF THE ASSOCIATED ELEVATOR CAR, MEANS MOUNTEING THE ELEVATOR CARS FOR MOVEMENT RELATIVE TO THE STRUCTURE TO SERVE THE FLOORS, DOWN FLOOR CALL REGISTERING MEANS OPERABLE FOR REGISTERING A CALL FOR DOWN ELEVATOR SERVICE FROM EACH OF A PLURALITY OF SAID FLOORS, UP FLOOR CALL REGISTERING MEANS OPERABLE FOR REGISTERING A CALL FOR UP ELEVATOR SERVICE FROM EACH OF A PLURALITY OF SAID FLOORS, CAR CALL REGISTERING MEANS FOR EACH OF THE ELEVATOR CARS OPERABLE FOR REGISTERING A CALL FOR EACH OF A PLURALITY OF SAID FLOORS WHICH MAY BE DESIRED BY LOAD IN THE ASSOCIATED ELEVATOR CAR, AND SELECTING MEANS FOR SELECTING AN AVAILABLE ONE OF THE ELEVATOR CARS TO PROVIDE DOWN ELEVATOR SERVICE FROM ONE OF SAID INTERMEDIATE FLOORS A FIRST ONE OF SAID ELEVATOR CARS BEING AVAILABLE FOR SELECTION BY THE SELECTING MEANS WHILE SUCH CAR IS ADJACENT AN INTERMEDIATE ONE OF THE FLOORS WHILE A CALL IS REGISTERED BY THE UP FLOOR CALL REGISTERING MEANS FOR A FLOOR ABOVE SUCH FIRST ELEVATOR CAR, THE SELECTING MEANS COMPRISING ASSIGNING MEANS FOR ASSIGNING AN AVAILABLE CAR SELECTED BY THE SELECTING MEANS TO ANSWER A CALL FOR SERVICE REGISTERED BY ONE OF THE DOWN FLOOR CALL REGISTERING MEANS AT AN INTERMEDIATE ONE OF THE FLOORS.