Feb 1, 2008 12:00 PM, By David A Kolman

LIFT DESIGNS

Six main types of lifts are used in truck maintenance facilities: inground lifts, pit lifts, two-post surface lifts, four-post surface lifts, parallelogram lifts, and mobile column lifts.

Inground lifts are available in two- or three-post designs. They engage the vehicle by its axles. Intended for most preventive maintenance and repair tasks, lifting capacity is typically up to 90,000 pounds.

Pit lifts, common in European service garages, are new to North America. Axle-engaging lifts are added to existing service pits to expand the maintenance and repair tasks that can be performed. Lifting capacity is up to 44,000 pounds.

Three pit lift models are floor-running, rail-mounted, and suspended. Floor-running pit lifts have caster wheels so technicians can roll them anywhere in the pit. Rail-mounted lifts move along a rail system at the bottom of the pit. Suspended pit lifts ride on rails installed at the top of the pit.

The most widely used vehicle lifts in the world are the two-post frame-contact surface design. Two sets of lifting arms are attached to two columns. The vehicle is driven between the columns, and the arms are manually positioned under the vehicle to lift it at designated pick-up points on the frame. Two-post lifts typically come in asymmetrical and symmetrical designs. Lifting capacity is up to 18,000 pounds.

With four-post drive-on surface lifts, the vehicle is driven onto a runway that is then raised. These lifts are one of the fastest to use because no set-up is required to raise the vehicle. Lifting capacity is up to 60,000 pounds.

Parallelogram lifts, as their name implies, rise using a parallelogram motion. Similar to the four-post drive-on surface lifts, the runway is raised after the vehicle is driven onto it.

Three versions of parallelogram lifts are surface mount, surface with recessed mount, and flush mount. Lifting capacity is up to 130,000 pounds.

The fastest-growing category of above-ground lifts for the heavy duty market is mobile column lifts. This design consists of four or six portable columns linked by a common control circuit.

The columns are wheeled to the vehicle, then connected together via control cables for synchronized lifting. The columns engage at the vehicle's wheels. Lifting capacity ranges from 60,000 to more than 90,000 pounds.