Mechanical toys are low-tech toys that move through some kind of mechanical process. The most well-known categories of mechanical toys are windup mechanical toys, cam toys and crank toys.
According to the article "Your Kids Will Love Mechanical Retro Toys" at ideamarketers.com, mechanical toys encourage imagination, curiosity and creativity.
A spring inside the toy powers windup mechanical toys. The child uses a key to wind the spring, which allows the toy to move for several minutes.
These mechanical toys use a cam attached to a crank to convey kinetic energy from you to the cam. The set-off-centre cam provides uneven rotation allowing the toy to move when cranked.
Related to cam-powered mechanical toys, crank toys use a combination of several cams in a single toy. This type of toy can exhibit complex movement.
Traditionally, mechanical toys have been made of wood or tin. Some modern mechanical toys are still made of the traditional wood and tin materials, while others are made of plastic.