When the car is pulled back, it winds up an internal coil spring by engaging the motor with a clutch. When the car is released, the spring unwinds and propels the toy forward. Energy is stored quickly during pullback but gets released slowly during forward motion.

How does a pull toy work?

A pull toy works when a child usually between the ages of 2-3 holds the end of a string and pulls the toy in a straight line along a smooth surface. When the toy is pulled the wheels begin to turn as well, there is usually a mechanism like a cam and follower that is making a specific body part move.

How does a wind up car work?

Pull the car backwards while pushing down and the motion of the turning wheels is stored as energy in a coiled spring inside the big central toothed wheel. Let go and it unwinds, propelling the machine forward. When the spring has fully sprung, a clutch disengages and lets the car roll free.