| 摘要 |
The unit comprises two variable-length pedal cranks (20) having a common rotation pin (21) of transverse axis (A), and a mechanism (34, 35, 36) for varying the length of the two pedal cranks (20) on the basis of their angular position; the position of the axes of the pedals (25) in the vertical plane of projection defines, as the angular position of the pedal cranks (20) varies, an endless closed curve (F) about a reference axis (R) which is displaced by an angle of about 15 degrees forwards from the axis (N) passing through the center of the seat (11) of the bicycle and intersecting the axis (A) of the pin (21). The endless curve (F) comprises an upper portion, extending through at least 60 degrees of rotation of the pedal crank about the upper point of its intersection (Ta) with the reference axis (R), in which the length of the pedal crank (20) is less than the mean value (LM) thereof, in the remaining part of the endless curve (F) the length of the pedal crank being greater than the mean value (LM); the point in which the length of the pedal crank reaches its maximum value (Lmax) is in a position between 40 and 120 degrees after the upper point of intersection (Ta)
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