Which term describes the device used to translate rotary drive into linear lift motion on escalators?

• A. Drive Unit
• B. Safety Governor
• C. Aircraft Cable Design
• D. Rack and Pinion

Answer: (D)

When you need to turn the motor’s spinning motion into the up-and-down movement of the steps, you use a rack-and-pinion arrangement. The drive motor turns a pinion gear, which meshes with a straight rack attached to the step carriage. As the pinion rotates, it travels along the rack, moving it in a straight line and thereby lifting or lowering the steps in a smooth, synchronized way. This setup provides precise linear motion from a rotary source, which is exactly what’s needed for the escalator’s vertical travel.

The other terms operate in different roles: the drive unit supplies power, the safety governor controls speed, and an aircraft cable design refers to a different lifting system—none of these directly convert rotary drive to linear lift like a rack and pinion does.