Stacker crane

Claim 1

LOAD TRANSFER APPARATUS HAVING LOAD HANDLING MEANS MOVABLE VERTICALLY AND HORIZONTALLY IN AN AISLE BETWEEN VERTICALLY AND HORIZONTALLY SPACED LOAD SUPPORT MEANS COMPRISING OVERHEAD CARRIER MEANS MOVABLE PARALLEL WITH SAID AISLE; A TROLLEY MOVABLE TRANSVERSELY OF SAID AISLE ON SAID CARRIER; POWER MEANS FOR MOVING SAID TROLLEY; A MAST DEPENDING FROM SAID TROLLEY AND LATERALLY MOVABLE IN SAID AISLE BY SAID TROLLEY; SAID LOAD HANDLING MEANS CARRIED BY SAID MAST; SAID LOAD HANDLING MEANS BEING MOVABLE UP AND DOWN SAID MAST AND HAVING GENERALLY HORIZONTAL, CANTILEVERED LIFTING MEANS ROTATABLE FROM ONE SIDE OF SAID AISLE TO THE ANOTHER AND ADAPTED TO PICK UP OR DEPOSITE A LOAD FROM ANY OF SAID LOAD SUPPORT MEANS ON EITHER SIDE OF SAID AISLE; POWER MEANS FOR ROTATING SAID LIFTING MEANS; POWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UP AND DOWN SAID MAST; SAID TROLLEY ADAPTED TO POSITION SAID MAST TOWARD ONE SIDE OF SAID AISLE WHEN SAID CANTILEVERED LIFTING MEANS IS ORIENTED TOWARD THE OTHER SIDE OF SAID AISLE IN SUCH A MANNER AS TO MINIMIZE THE NECESSARY WIDTH OF SAID AISLE FOR ALLOWING VERTICAL AND HORIZONTAL MOVEMENT OF SAID LOAD HANDLING MEANS IN SAID AISLE; AND A SAFETY INTERLOCK CONNECTION BETWEEN SAID TROLLEY MOVING POWER MEANS AND SAID POWER MEANS FOR ROTATING SAID LIFTING MEANS ENABLING OPERATION OF SAID POWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UP AND DOWN SAID MAST ONLY WHEN SAID MAST AND SAID LIFTING MEANS ARE ORIENTED TOWARD OPPOSITE SIDES OF SAID AISLE.