| 摘要 |
PROBLEM TO BE SOLVED: To provide an expansion/contraction crank mechanism in which an rider can outstandingly reduce burden of leg force when riding on a continuing upslope in an adverse wind. SOLUTION: A fixing sprocket gear 2 is fixed to a spindle bearing and a crank 4 is pivotally mounted on a spindle end penetrated with a spindle 3. A gear in which a turning sprocket gear 6 is pivotally mounted on an inner shaft side is engaged with a support shaft 5 at a distal end by a chain 7. Motion of a sub-crank pedal 8 for stopping an inclination angle pivotally mounted to an outer shaft end side to a constant and moving in a reverse rotation and two inclination angles rotating/varying of a crank 4 are coincident in a linear shape. Therefore, the length of the expansion/contraction crank is elongated to the longest and a return side crank is shortened to a half by superposing it. Two fulcrums fixed to the frame 1 are superposed on the fulcrum of an inner/outer diameter of the spindle bearing and the expanding/contracting crank and the fixed fulcrum are one-rotated without hitting them. A unique driving mechanism for expanding/contracting the length from the spindle 3 to the pedal is provided. COPYRIGHT: (C)2006,JPO&NCIPI
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