Patent ID: 8726753

Claim:
A gear, comprising: an outer ring defining a plurality of first fixing holes in its periphery; an inner ring concentric with the outer ring, and defining a plurality of second fixing holes in its periphery, the second fixing holes corresponding to the first fixing holes, wherein each first fixing hole, the corresponding one of the second fixing holes, and the center of the rings are in alignment, and defining an axis of radial movement between the pair of the first and second fixing holes; a plurality of gear teeth; and a plurality of elastic member sleeved on the respective gear teeth; wherein each gear tooth extends through a pair of corresponding first and second fixing holes, and being movable along the axis defined by the first and second fixing holes, each gear tooth comprises an engaging portion located outside the outer ring, the engaging portion comprises a meshing surface and a stopper surface having a size greater than the first fixing hole; each elastic member is configured to deform and rebound during the movement of the corresponding gear tooth so as to absorb shock generated by the gear.