Screw Drive – How Does It Work?

A screw drive is use in many commercial and residential wheelchair lifts. This utilizes a long screw shaft and drive nut to raise and lower the platform. The speed of the screw drive wheelchair lift is fairly slow, so it is typically used in applications with 6 feet or less vertical travel.

An electric motor resides between the rails. It is connected to the screw shaft by belts. The drive nut is attached to the platform. As the screw shaft rotates, the drive nut (and platform) are moved up or down along the shaft. A shallow pit or ramp is required for this wheelchair lift.

The screw drive wheelchair lift is considered machine-room-less; The controller and motor unit are located in the hoistway, eliminating the need for a separate machine room closet.