The self-stabilizing vertical lift from Suspended Climbing Systems, Tulsa, Okla. (suspendedclimbingsystems.com) relies on roller chains and drive sprocket rather than cables for a safer, more-reliable vertical lift.

The device can lift up to 900 lb at 40 fpm for an unlimited vertical distance on a gated platform. The system includes a pair of heat-treated steel rollers and a heat-treated chain sprocket. The power chain roller climbs or descends the roller chains which are fixed at the upper and lower limits of vertical travel. Rollers help the drive sprocket engage the roller chain without weakening it by bending it around the sprocket. This eliminates wear and fatigue problems associated with steel cables used to lift and lower platforms.

A closed-loop hydraulic motor under solid-state control turns the main driving shaft, letting it descend slowly and under control. All drive and stabilizing mechanisms are underneath the platform so they’re easy to get at for maintenance but out of the way for traffic using the lift.

In case of a power loss or failure of the dual disc brakes, transmission, or motor, the platform can descend safely without waiting for power to be restored. For safety, the lift will not move unless the gates are closed and locked. Nor will it move if overloaded. Stabilizer rails prevent the lift from swaying in high winds.

Edited by Stephen J. Mraz