Reinforced plastics bicycle frame - has rigid centre reinforcement for crank shaft and rider support

摘要

The frame for a bicycle consists of a beam of reinforced plastics material. This is fitted with interlocks which allow the fitting of various parts of the assembly. The beam has a rigid central part between a housing for fixing the crank shaft and the rider's position adjustment. The end beam sections (AB) (CD) have variable flexibility but the central part (BCEF) is rigid to keep the rider's position fixed relative to the crank shaft. The flexible parts carry the wheels and give some flexibility to the rider.