DRIVE FOR BICYCLES

摘要

Drive for bicycles of the type which has a frame and a pair of pedals (1, 2) at respective sides of the frame, a driven rear wheel with a shaft (10) and a pair of swinging arms (3, 4), wherein each pedal (1, 2) forces respective ones of the swinging arms (3, 4) for periodic swinging movement in planes substantially parallel to the plane of the frame, so that the phase of movement is opposite at the two sides. Respective wires (6, 21) are coupled to each of the swinging arms (3, 4), respective wire drums are located at the two sides of the rear shaft, the wires (6, 21) are wound around the associated one of the wire drums with a plurality of turns, and the drive comprises biasing means for keeping the wires (6, 21) stretched during said swinging movement. The wire drums comprise respective additional windings (18, 23) made of tension wires (14, 15) in addition to the windings (9, 22) of the wires (6, 21), and the tension wires when leaving the additional windings (18, 23) are wound around respective spools of a double tension drum (20) constituting the biasing means. The spools can be turned around a common shaft relative to each other and they are interconnected by means of a resilient tension means.