The anatomy of a handling truck covers the parts and technical characteristics common to pallet trucks, stackers and forklifts: forks, carriage, mast, tiller, as well as concepts like free lift, residual capacity or center of gravity. This entry brings together twelve technical terms, each too narrow to justify a page of its own.
Forks
The forks are the two horizontal arms that slide under the pallet to lift it. The standard length is 1,150 mm, sized for the EUR pallet (800×1,200 mm); a shorter 800 mm version exists for tight spaces such as the inside of a truck. Fork spacing is adjustable to fit different pallet formats.
Carriage
The carriage (or fork carriage) is the vertical plate the forks are mounted on. It slides along the mast and carries the tilt mechanisms and, in some cases, side-shift. Its strength directly determines the actual load capacity at each lift height.
Simplex, duplex and triplex mast
The mast is the vertical structure that guides the carriage and forks up and down. A simplex mast has only one stage, for a limited lift height. A duplex mast adds a second telescoping stage, which generally allows for greater free lift. A triplex mast, with three stages, reaches the greatest lift heights while keeping a lower collapsed height, useful for passing through doors or low-clearance zones.
Tiller
The tiller is the steering arm of a walk-behind pallet truck or stacker. The operator, walking alongside, uses it to steer the machine, brake, and operate lifting via a built-in control. On electric models, its position (high, low, neutral) also controls forward, reverse and emergency stop.
Free lift
The free lift is the height the forks can rise to before the mast itself extends above its collapsed height. It is a key criterion for working under a low ceiling or inside a truck, where any mast extension would be blocked by insufficient clearance.
Rated capacity
The rated capacity is the maximum load the truck can lift under reference conditions defined by the manufacturer (centered load, at a given distance from the fork heel, usually 500 mm, at a reference lift height). It is shown on the machine's data plate.
Residual capacity
The residual capacity more precisely refers to the maximum load the truck can actually lift at a given lift height and load center distance, this capacity decreasing as height or distance increase, according to the manufacturer's load chart. This definition, not standardized in any single source consulted, remains a working definition to be confirmed with the manufacturer for precise regulatory use.
Center of gravity
The center of gravity is the point where the resultant weight of the load (and the machine) applies. Its position, distance from the fork heel, height above the ground, directly determines the truck's stability and therefore its residual capacity at each lift height.
PU wheels
PU wheels (polyurethane) fit most pallet trucks and stackers used on smooth floors. They roll quietly, offer low rolling resistance, and are gentle on floors, at the cost of somewhat lower load resistance than nylon.
PPS
Wheels or rollers made of PPS use a rigid technopolymer, harder and more resistant to wear and chemicals than polyurethane. They mainly fit stabilizer wheels or harsh environments, at the cost of a less comfortable ride; their exact composition varies by manufacturer.
Load rollers
Load rollers are small secondary wheels, located on either side of the forks or under the carriage, that provide the truck's lateral stability and make it easier to enter narrow racking slots, in addition to the main wheels.
Stacking
Stacking is the action of piling palletized loads, or placing them at height in racking, using a stacker or a forklift. "Stacking height" refers to the maximum usable lift height for this operation.
FAQ
What is the difference between a duplex and a triplex mast?
A duplex mast has two telescoping stages, a triplex three. The triplex reaches greater lift heights while keeping a lower collapsed height, which makes it easier to pass under low ceilings or into closed trucks.
What is the free lift of a pallet truck or stacker?
It is the height the forks can rise to before the mast itself starts to extend. It is critical for working under a low ceiling, inside a truck, or in a zone with limited headroom, without hitting the structure.
Why does residual capacity decrease with height?
The higher a load is lifted, the further it moves from the machine's center of gravity, which reduces its stability. The manufacturer therefore limits the allowed load as lift height or load center distance increases, according to a load chart specific to each model.
Related terms
Pallet truck · Manual pallet truck · Stacker · Forklift truck · Reach truck · CACES · Periodic inspection (VGP).
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