Up to date, there are many devices for putting a limb of an animal-shaped toy in motion. However, the mechanisms are very complicated. Traditional devices usually use gears or cams as an actuation source and are composed with rectangular slide plate sets or rack and pinion sets as an activity track to act upon the toy. Approximately, ninety-five percent of reciprocating type toys apply the rack and pinion set to form a track and the rest of them apply a rectangular slide plate set. Therefore, traditional devices have the following drawbacks:
1. The activity track is a simple straight line whose motion is monotonous.
2. The manufacturing cost is high and assembly is relatively difficult.
3. The type of motion cannot be changed.