| 摘要 |
This invention relates to a gear crank suitable for use in a pedal vehicle comprising a crank shaft (11) and a pair of crank arms (12,13) at respective axial ends of said crank shaft (11) and a chain wheel support means (2) with an annular chain wheel (3) thereon, said chain wheel support means (2) having a plurality of radially extending stays (4-7). Known such cranks are heavy and create significant drag during pedalling. …<??>According to this invention the chain wheel support means (2) has two groups each of two stays (4,5 and 6,7), said stays of each of said groups being disposed angularly rearwardly of a respective crank arm (12, 13) with respect to the forward driving direction of the gear crank at a rotational angular spacing (O1) from an upper dead point thereof and corresponding substantially to exertion of a maximum torque on said crank arms (12, 13) during pedalling in use of said gear crank. |
