| 摘要 |
Two pedal carriages guided on guide rollers are arranged in a guide frame and are connected via pulley tackles, by the cords of the latter, to the flap carriages. The pedal carriages are connected to each other at the opposite ends by a connecting cable, deflected by a roller. The flap carriages also have a similar connection, as a result of which the system is friction-actuated. The guide frame is connected to a strap-on saddle by a connecting piece and a receiving piece. Both pressure and tension are exerted on the pedals, a short linear foot stroke being converted by the pulley tackle into a long flap stroke. The flaps, which are attached to the flap carriage in the form of wings, perform a reciprocal movement to the movement of the foot. During forward movement they spread out and exert a thrust, whereas during the backward movement they close and, because of their curvature, form a favourable shape for flow.
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