Patent ID: 7823698

Claim:
A forklift mast assembly, comprising: a three-stage mast consisting of an outer mast, a middle mast, and an inner mast, each mast slidably and nestably engaging an adjacent mast and configured for positive and negative lift along the length of each mast; a first linkage system comprising a cylinder assembly mounted on the outer mast and a chain fixed at opposite ends to the outer and middle masts, therebetween engaging a pulley on the cylinder assembly, wherein the first linkage system achieves a 2:1 movement ratio of the middle mast to the cylinder assembly; and a second linkage system comprising a chain fixed at opposite ends to the outer and inner masts, therebetween engaging a pulley on the middle mast, wherein the second linkage system achieves a 4:1 movement ratio of the inner mast to the cylinder assembly.