Elevator Types: Traction Elevators

Geared and gearless traction Elevators

Traction elevators are rather common. Like all elevators, they must meet certain specifications and regulations. They must also be inspected often to ensure safety. Failure to inspect an elevator could be a contributing factor to negligence that may entitle you to a large cash settlement if you've been in an elevator accident. Fill out this simple form for your free case evaluation with our experienced elevator accident lawyers.

Geared Traction machines are driven by AC or DC electric motors. Geared machines use worm gears to mechanically control movement of elevator cars by "rolling" steel hoist ropes over a drive sheave which is attached to a gearbox driven by a high speed motor. These machines are generally the best option for basement or overhead traction use for speeds up to 350 ft/min.

Gearless Traction machines are high speed electric motors powered by AC or DC current. In this case the drive sheave is directly attached to the end of motor.

In each case, cables are attached to a hitch plate on top of the cab or may be "underslung" below a cab, and then looped over the drive sheave to a counterweight attached to the opposite end of the cables which reduces the amount of power needed to move the cab. The counterweight is located in the hoistway and rides a separate rail system; as the car goes up, the counterweight goes down, and vice versa. This action is powered by the traction machine which is directed by the controller, typically a relay logic or computerized device that directs starting, acceleration, deceleration and stopping of the elevator cab. The weight of the counterweight is typically equal to the weight of the elevator cab plus forty to fifty percent of the capacity of the elevator. The grooves in the drive sheave are specially designed to prevent the cables from slipping. "Traction" is provided to the ropes by the grip of the grooves in the sheave. As the ropes age and the traction grooves wear, some traction is lost and the ropes must be replaced and the sheave repaired or replaced.

Some elevators have a system called compensation. This is a separate set of cables or a chain attached to the bottom of the counterweight and the bottom of the elevator cab. This makes it easier to control the elevator because the weight will flucuate less over the entire system. If the elevator cab is at the top of the hoistway, there is a short length of hoist cable above the car and a long length of compensating cable below the car and vice versa for the counterweight. If the compensation is cables there is an additional sheave in the pit below the elevator, to guide the cables. If the compensation is a chain, the chain is guided by a bar mounted between the counterweight rails.

If you've been injured in an Elevator Accident, please fill out our simple Elevator Accident Form. A Client Relations Representative will contact you shortly to discuss your potential case. Feel free as well to call us at (800) 476-6070 or email us at clientrelations@weitzlux.com.

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see also:

Passenger Passenger Elevators - Elevator Accidents
Passenger Elevators - FREE evaluation by an elevator accidents lawyer

Handling Belts Material Handling Belts - Grain Elevators and other Material Handling Belts
Material Handling Belts - Type of elevator used to transport material.

Elevator Types Elevator Accident/Escalator Accident Attorneys - Elevator Types and Uses
Escalator, Elevator Accident Attorneys - FREE Lawsuit Evalutaion-Types