pulley, roller
轆 centers on a wheel-like device that turns to move or lift things: a pulley or roller. Both meanings share the idea of a rotating cylinder that guides or transports.
轆 combines 車 (vehicle, wheel) with 鹿, which likely contributes the sound. The character originally referred to a pulley or windlass, a wheeled device for lifting.
A cart 車 with a deer 鹿 on it? Imagine a deer turning a large wheel on a cart to lift heavy loads—that's a pulley or roller.
For ロク, picture a lock on the pulley that keeps it from turning: lock -> ロク, and the locked pulley stays still.