Patent ID: 6478323
Filing Date: 2002-11-12
Classification: B62M

Abstract:
A transmission device for a bicycle having a frame, a bottom bracket mounted on the frame and a hub with a rear wheel axle, the transmission device comprising:a front casing; a crank axle rotatably mounted in the front casing and having two ends each extending out from the front casing to be adapted to be connected with a pedal; a drive gear rotatably attached to the crank axle; a tube securely connected to the front casing with one end of the tube; a rear casing securely connected to the other end of the tube; a transmission shaft rotatably received in the tube and having a first end extending into the front casing and a second end extending into the rear casing; a front gear rotatably attached to the first end of the transmission shaft and received in the front casing to mate with the drive gear; a rear gear rotatably attached to the second end of the transmission shaft and received in the rear casing; and a driven gear rotatably received in the rear casing and engaging with the rear gear to be adapted to be attached to the hub; wherein two ears extend from the front casing; a connector is secured to each ear and has a circular protrusion adapted to be fit into one end of the bottom bracket; and multiple bolts extend through the ears, the connectors and a nut screws onto each bolt to attach the front casing to the bottom bracket by the connectors.