When did the patent for bicycle transmission expire?

The patent is valid for 20 years. According to the bicycle patent inquiry, the protection period is 20 years. The validity period of a patent is 20 years, which shall be uniformly stipulated by the Patent Office. Bicycles, also known as bicycles or bicycles, are usually small land vehicles with two wheels. After people get on the bus, they are green and environmentally friendly vehicles powered by pedaling.