Importance

Loading Importance Indicators...

Abstract

A crank system mounted to a drive sprocket of a bicycle includes a crank arm secured to the drive sprocket and disposed at both sides thereof, the crank arm having two bent ends; and two telescopic assemblies each comprising a bar having one end fixedly secured to either end of the crank arm, the bar having a cross section of polygon, the bar including a plurality of longitudinal notches, a sliding tube slidably put on the bar, the sliding tube including a surface opening communicating with the bar, and a pivotal lock member in the surface opening, the lock member being adapted to either dispose in one of the notches in a locked position of the telescopic assembly or clear the notch in a unlocked position of the telescopic assembly. This length adjustable bicycle crank system can save force when pedaling.

Loading the Abstract Image...

First Claim