In a rack and pinion drive, what moves the gate?

• A. The interaction of rack teeth and pinion teeth moves the gate
• B. The hydraulic cylinder extends to move the gate
• C. Chain and sling drive the gate
• D. Belt and pulley assembly move the gate

Answer: (A)

In a rack and pinion drive, the gate moves because the pinion gear rotates and meshes with a straight rack. As the pinion turns, its teeth push against the rack teeth, converting the rotary motion of the gear into linear motion of the rack, and the gate moves along with that rack. This direct meshing action is what produces smooth linear movement without needing other drive methods. Hydraulics, chains, belts, or pulleys describe different ways to move something, but they don’t implement the rack-and-pinion conversion that actually drives the gate in this system.