| 摘要 |
<p>The drive device comprises a toothed front wheel (2) pivotable about a first straight line (T) with respect to which the toothed wheel (2) presents variable radii. A tread crank (3b) is pivotably arranged about a second straight line (D) horizontally offset with respect to the first straight line (T). Another tread crank (3a) is so connected to the toothed wheel (2) that it is inclined by an angle (α) comprised between 45o and 135o in the pedalling direction with respect to the upwardly maximum radius of the toothed wheel (2). When the second tread crank (3a) is in the horizontal position, the first tread crank (3b) is also in a horizontal position. Both tread cranks (3a, 3b) are coupled to each other by a shaft (A) which traverses the toothed wheel (2) and which is fixedly connected to a coupling lever (5) as well as by an oblong hole or slide guiding (6, 10) which enables the relative motion of the two tread cranks (3a, 3b).</p> |
