Patent ID: 8302508

Claim:
A two-way propelling type transmission mechanism for bicycle, comprising a casing covered with a cover, a driving axle rotatably supported in said casing, two pedals suspending outside said casing, two cranks coupled between two opposing ends of said driving axle and said two pedals, a directional gear mounted on said driving axle inside said casing, a first gear mounted on said driving axle in said casing and disposed at one side relative to said directional gear and having a tubular gear shaft and a series of clutch teeth located on one end of said tubular gear shaft, a gear cluster mounted on an opposite end of said tubular gear shaft outside said casing, a second gear mounted on said driving axle in said casing and disposed at an opposite side relative to said directional gear and having a series of clutch teeth at one side thereof, a transmission axle rotatably mounted in said casing and arranged in a parallel manner relative to said driving axle, a first transmission gear fixedly mounted on one end of said transmission axle and meshed with said first gear, a second transmission gear fixedly mounted on an opposite end of said transmission axle, a chain coupled between said second gear and said second transmission gear, a bearing ring mounted on said directional gear, a pull spring connected to said bearing ring and imparting a pull force to said bearing ring and said directional gear to keep said directional gear in mesh with the series of clutch teeth of said first gear, and a control line connected to said bearing ring and operable to pull said bearing ring and said directional gear away from the series of clutch teeth of said first gear into engagement with the series of clutch teeth of said second gear.