| 摘要 |
A crank device which can produce a large torque without increasing the locus of the crank arm. The crank arm has first and second arms which are longitudinally slidably coupled together through a pinion. The second arm is formed with two sets of rack teeth on both sides of the pinion. The pinion has along its circumference a plurality of teeth which are adapted to alternately come into mesh with the respective sets of rack teeth every time the crank arm makes a half turn in the same direction. Thus, the entire length of the crank arm alternately becomes maximum and minimum every time the crank arm turns by 180 DEG . By applying a driving force to the crank arm when the length of the crank arm is maximum, it is possible to produce a large torque. <IMAGE> <IMAGE> |
