| 摘要 |
<p>A pedal drive system (9) for propelling a multi-wheeled cycle has a cycle frame (10) that has a steerable front wheel (12) and at least one driven wheel (14); first and second pedal arms (21, 22), each having a support member (23, 24) for supporting a respective foot of the user. Each support member (23, 24) is hingably supported by said cycle frame (10) at a proximal end (21a, 22a) of said arm. A drive spindle (40) is supported by said cycle frame (10) between said first and second pedal arms (21, 22). The drive spindle (40) has a toothed member for transmitting a driving force to said at least one rear wheel (14), using a flexible transmission element (50) and a rear wheel toothed member (60). The pedal drive system (9) further has first and second two-bar linkages connecting respective said pedal arms (21, 22) to the said drive spindle (40). The two-bar linkages further have an inner bar, and an outer bar, and wherein said inner bars have one crank pin G, I each, respectively, located between the distal (21b, 22b) and proximal (21a, 22a) ends of the said pedal arms (21, 22). Each crank pin G, I remains 180 degrees apart around the said drive spindle (40), and wherein both said outer bar linkages F, H have differing angular relationships with respect to the said respective pedal arms (21, 22) at said first and second pedals' end of stroke positions. One or the other said first and second pedal arms (21, 22) can always apply rotation force to the said inner bars' crank pins G, I without the necessity of rotational force being back to the said inner bars' crank pins G, I by means of the rotation of the wheel.</p> |
