STRETCHABLE CRANK ARM FOR BICYCLE

摘要

PURPOSE: A variable crank arm for a bicycle is provided to increase torque due to increase in the length of the variable crank arm while pressure is applied to a pedal and to rapidly enter a second cycle due to the recovery of the length of the crank arm while pressure is not applied to the pedal. CONSTITUTION: A variable crank arm(1) for a bicycle comprises a slide guide(5), a spring(10), a fixed spring support(8), and a variable spring support(7). The sliding guide enables the reciprocating stroke of the body(2b) of a pedal axis side. The sliding guide is installed on one surface of the body(2a) of a crank axis side. The spring, the fixed spring support, and the variable spring support are installed on the insertion unit of the body of the crank axis side. The force of the spring is applied to the opposite direction to the extended direction of the body of the pedal axis side.