Bicycle air pump structure

摘要

A bicycle air pump includes a cylinder adapted to be secured to the bicycle frame having a cylinder bore within which a piston reciprocates, a crank shaft rotatably supported on the cylinder and drivingly coupled to the piston by means of a connecting rod and a driving mechanism for coupling the crank shaft to the bicycle chain to be driven thereby so that when the bicycle pedals are actuated to drive the bicycle chain, the bicycle chain forces the crank shaft to rotate and thus making the piston reciprocate within the cylinder bore to pump air through an outlet of the cylinder.