Mechanical speed changing system for bicycles has front and rear axles couple to frame, together with speed changing elements to form independent unit inside groove

摘要

The system has front (2) and rear tubular axle (3) receiving movement via pairs of sprocket wheel which intermesh with axle. The axles are coupled to a frame (1), together with the speed changing elements to form an independent unit (32) inside the a groove (33). The rear axle has idler gears (9) which mesh with other idler gears (10) that are connected to a coaxial tube (11), freely connected to the front axle.