traction
Elevators raised and lowered along tracks by cables, using a counterweight for balance.
Traction elevators are the most common type of vertical lifts used in buildings. The cab is lifted by cables along a trackway (with or without gears), and its weight is counterbalanced by a counterweight that moves in the opposite direction.
Because the cab and counterweight are nearly equal in weight (usually the counterweight exceeds the cab by roughly half of the allowed passenger or freight capacity), the role of the cables is not to lift dead weight so much as to overcome forces of traction built into the cab/counterweight system.
Traction elevators use far less energy than hydraulic elevators, and are common in tall buildings as well as low-rises and other structural types. They are the standard system for any kind of building with heavy traffic.
More specific definitions
2 sub-definitionsRelated definitions
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hydraulic
Elevators raised by a fluid-powered cylinder-and-piston mechanism and lowered by controlled release of fluid. -
paternoster
Doorless vertical lift cabins carried upright around a continuously moving loop with upward and downward shafts. -
platform lift
A platform raised and lowered mechanically to transport persons and cargo between different levels. -
rack and pinion
Elevators that climb along a toothed rack through the rotation of pinion gears engaged to the rack. -
scissor lift
Elevators raised and lowered from underneath by an extendable lattice of criss-crossed folding beams.