Triple stage upright for lift truck

Claim 1

A MAST ASSEMBLY FOR A LIFT TRUCK COMPRISING FIRST, SECOND AND THIRD UPRIGHT SECTIONS, SAID SECOND SECTION BEING MOUNTED FOR VERTICAL MOVEMENT ON SAID FIRST SECTION, SAID THIRD SECTION BEING MOUNTED FOR VERTICAL MOVEMENT ON SAID SECOND SECTION, A LOAD CARRIAGE MOUNTED FOR VERTICAL MOVEMENT ALONG SAID THIRD SECTION, A CYLINDER ASSEMBLY MOUNTED BETWEEN SAID SECOND AND THIRD SECTIONS, SAID ASSEMBLY HAVING A FIRST HYDRAULIC CYLINDER SUBSTANTIALLY THE LENGTH OF ONE OF THE UPRIGHT SECTIONS CONNECTED TO SAID SECOND SECTION, A SECOND HYDRAULIC CYLINDER SLIDABLE ON THE SAID FIRST CYLINDER, CONNECTED TO THE THIRD SECTION AND HAVING A LENGTH SUBSTANTIALLY THE LENGTH OF ONE OF THE UPRIGHT SECTIONS, A THIRD HYDRAULIC CYLINDER SUBSTANTIALLY ONE-HALF THE LENGTH OF ONE OF THE UPRIGHT SECTIONS AND SLIDABLE ON THE SECOND CYLINDER AND A FOURTH HYDRAULIC CYLINDER SECURED TO SAID SECOND CYLINDER AND SLIDABLE IN RELATION TO SAID THIRD CYLINDER, SAID FOURTH CYLINDER AND THIRD UPRIGHT SECTION BEING IMMOVABLE RELATIVE TO EACH OTHER, ANCHOR MEANS SECURED TO SAID FOURTH CYLINDER, FIRST SPROCKET MEANS MOUNTED AT THE UPPER END OF THE THIRD CYLINDER AND ROTATABLE ABOUT AN AXIS TRANSVERSE OF THE TRUCK, FIRST CHAIN MEANS EXTENDING OVER SAID SPROCKET MEANS AND CONNECTED AT ONE END TO THE LOAD CARRIAGE, SECOND SPROCKET MEANS MOUNTED AT THE LOWER END OF SAID SECOND UPRIGHT SECTION AND ROTATABLE ABOUT AN AXIS LONGITUDINAL OF THE TRUCK, AND SECOND CHAIN MEANS EXTENDING BENEATH SAID SECOND SPROCKET MEANS AND CONNECTED AT ONE END THEREOF TO THE UPPER END PORTION OF THE FIRST UPRIGHT SECTION, THE OPPOSITE ENDS OF SAID FIRST AND SECOND CHAIN MEANS BEING SECURED TO SAID ANCHOR MEANS.