Abstract: A wheel assembly includes a wheel having an axle, and a constant force mechanism coupled to the wheel. The constant force mechanism includes a horizontal support, a horizontal carriage associated with the horizontal support, a vertical support oriented perpendicular with respect to the horizontal support, a vertical carriage associated with the vertical support, and a rigid arm that is pivotally coupled with the horizontal carriage, the vertical carriage, and the axle. The rigid arm is coupled with the vertical carriage at a point intermediate where the rigid arm is coupled with the horizontal carriage and the axle. The horizontal carriage is capable of being urged along the horizontal support, and the vertical carriage is capable of being urged along the vertical support.

Abstract: A lift truck can include a mast and a lift cylinder. The lift cylinder can include a piston rod and a cylinder housing. The lift truck also can include a piston rod retention mechanism that restricts movement of the lift cylinder in a direction lateral to an axial direction when the mast is in an extended position.

Abstract: A wheel assembly includes a wheel having an axle, and a constant force mechanism coupled to the wheel. The constant force mechanism includes a horizontal support, a horizontal carriage associated with the horizontal support, a vertical support oriented perpendicular with respect to the horizontal support, a vertical carriage associated with the vertical support, and a rigid arm that is pivotally coupled with the horizontal carriage, the vertical carriage, and the axle. The rigid arm is coupled with the vertical carriage at a point intermediate where the rigid arm is coupled with the horizontal carriage and the axle. The horizontal carriage is capable of being urged along the horizontal support, and the vertical carriage is capable of being urged along the vertical support.

Abstract: A wheel assembly includes a constant force mechanism and a wheel coupled to the constant force mechanism. The wheel is displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force on the wheel in the dimension. In one aspect, the wheel is displaceable in a first regime and a second regime. For a wheel displacement in the first regime, the constant force mechanism imparts a substantially constant force on the wheel, and for a wheel displacement in the second regime, the constant force mechanism imparts a variable force on the wheel. The variable force can be linear or non-linear to the magnitude of the displacement in the second regime and is equal to or greater than the substantially constant force.

Abstract: A wheel assembly for a material handling vehicle includes a chassis, a first caster wheel mounted to the chassis, a second caster wheel mounted to the chassis, a torsion bar coupling the first caster wheel to the second caster wheel, and a constant force mechanism coupled to at least one of the first caster wheel, the second caster wheel and the torsion bar. The first and second caster wheels are displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force opposing a displacement in the at least one dimension.

Abstract: A lift truck can include a mast and a lift cylinder. The lift cylinder can include a piston rod and a cylinder housing. The lift truck also can include a piston rod retention mechanism that restricts movement of the lift cylinder in a direction lateral to an axial direction when the mast is in an extended position.

Abstract: A wheel assembly includes a constant force mechanism and a wheel coupled to the constant force mechanism. The wheel is displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force on the wheel in the dimension. In one aspect, the wheel is displaceable in a first regime and a second regime. For a wheel displacement in the first regime, the constant force mechanism imparts a substantially constant force on the wheel, and for a wheel displacement in the second regime, the constant force mechanism imparts a variable force on the wheel. The variable force can be linear or non-linear to the magnitude of the displacement in the second regime and is equal to or greater than the substantially constant force.

Abstract: A wheel assembly for a material handling vehicle includes a chassis, a first caster wheel mounted to the chassis, a second caster wheel mounted to the chassis, a torsion bar coupling the first caster wheel to the second caster wheel, and a constant force mechanism coupled to at least one of the first caster wheel, the second caster wheel and the torsion bar. The first and second caster wheels are displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force opposing a displacement in the at least one dimension.

Abstract: A system and method that maintains the dynamic stability of a material handling vehicle having a vertical lift. The method allows static vehicle properties, such as vehicle weight, wheelbase length, and wheel configuration, and dynamic operating parameters, such as vehicle velocity, floor grade, lift position, and load weight, to be accounted for when maintaining the dynamic stability of a moving material handling vehicle. The method may include calculating and predicting center-of-gravity parameters, wheel loads, and projected force vectors multiple times a second and adjusting vehicle operating parameters in response thereto to maintain vehicle stability.

Abstract: A system and method that maintains the dynamic stability of a material handling vehicle having a vertical lift. The method allows static vehicle properties, such as vehicle weight, wheelbase length, and wheel configuration, and dynamic operating parameters, such as vehicle velocity, floor grade, lift position, and load weight, to be accounted for when maintaining the dynamic stability of a moving material handling vehicle. The method may include calculating and predicting center-of-gravity parameters, wheel loads, and projected force vectors multiple times a second and adjusting vehicle operating parameters in response thereto to maintain vehicle stability.