Abstract: A materials handling vehicle is provided. The vehicle comprises a main body, a seat deck assembly including an operator seat, and structure for movably mounting the seat deck assembly to the main body. The seat deck assembly moves relative to the main body along a varying radius path.

Abstract: A lift truck having a frame and a two-stage telescopic mast in which an outer, movable mast is mounted to telescope over an inner mast which is fixed to the frame, each mast having a substantially continuous, unitary tubular body which provides superior strength characteristics in response to torsional loads and bending moments. The masts each include vertically extending beams, integral with the tubular bodies thereof, having tracks to receive rollers mounted to the beams so that the only contact between the masts is by the rollers. The beams of the outer mast include tracks which receive the rollers of a platform having a lifting fork structure and which is vertically movable relative to the outer mast.

Abstract: In a material handling vehicle having an operator platform, a sideshift carriage mounted for lateral movement relative to the platform, a traverse carriage mounted for lateral movement relative to the sideshift carriage and forks mounted to the traverse carriage, an improved sideshift control system monitors the position of the sideshift carriage to define home positions for the sideshift carriage relative to the platform. Two home positions are defined, one for the forks facing to each side of the vehicle. The home positions offset the sideshift carriage to one or the other side of the platform to substantially center the load on the vehicle such that a portion of the base of the forks extends a set distance beyond one side of the platform, and the load supported on the forks extends approximately an equal distance beyond the opposite side of the platform.

Abstract: An improved system for monitoring lift chains included within mast assemblies in material handling vehicles disables downward movement of the forks upon detection of a first level of slackness in a lift chain. Since upward movement of the forks is not disabled, the forks may be raised to clear any obstruction causing the chain slackness. A lift chain may also be monitored to detect a broken chain in which case all vertical movement of the forks is disabled. In a material handling vehicle wherein the operator is elevated along a first mast and the forks are elevated along a second mast connected to an operator's platform, dual lift chains in the first mast are individually monitored for both slackness and breakage while dual lift chains in the second mast are monitored in common primarily to detect slackness. Lateral and rotational movement of the forks is also disabled for detection of a slack or broken first mast lift chain, but not for detection of a slack or broken second mast lift chain.