Transmission system's i.e. gearbox, mechanical speed changing device for e.g. road bicycle, has movement transformation units transforming rotational movement of crank of bicycle into traction or releasing force of cables of derailleurs

摘要

The device (1) has rotational movement transformation units transforming rotational movement of a crank of a bicycle e.g. road bicycle, into a traction or releasing force of cables of front and rear derailleurs (3, 4), and a ratchet with a spring plate system fixed on a beam by a rivet, where the system is made of elastic material. The derailing units laterally displace an endless transmission chain (70k) between a set of toothed plates (7a-7c) or pinions (70a, 70j), using traction or releasing the cables. Mechanical control units control displacement of the derailing units. An independent claim is also included for a method for changing speed of a transmission system of a bicycle.