Patent ID: 8251389
Filing Date: 2012-08-28
Classification: B62M

Abstract:
1. A bicycle comprising a frame, a front wheel and a rear wheel rotatably mounted on the frame, a main transmission system including a crank axle rotatably mounted on the frame, two cranks mounted on opposite ends of the crank axle, two pedals mounted on the cranks, a front sprocket connected to the crank axle, a rear hub connected to the rear wheel, a rear sprocket connected to the rear hub, and a chain connecting the front sprocket and the rear sprocket, and an auxiliary power system, wherein the auxiliary power system includes: a base in the form of a disc fixedly mounted on the frame and adjacent to the front sprocket or the rear sprocket; an energy storage device connected to the base, and a ratchet device mounted on the front sprocket or the rear sprocket for connecting the energy storage device and the main transmission system; wherein when the cranks are turned in a rearward direction, the energy storage device is operable to store energy via the ratchet device, but when the cranks are turned in a forward direction and additional auxiliary assistance is desired, the energy storage device is operable to release the stored energy via the ratchet device to drive the rear wheel, wherein the auxiliary power system further includes a gear disc rotatably mounted on the base and connected to the power storage device, the gear disc having teeth at a circumference thereof, and the ratchet device having a first pawl connected to the front sprocket or the rear sprocket and a first spring urging the first pawl, which biases the first pawl to engage with the teeth of the gear disc in a normal state when no stored energy is being released, and wherein the power storage device is an energy storing spring received in an opening of the gear disc, the energy storing spring connected to the gear disc and the base respectively to be wound up by a rotation of the gear disc in the rearward direction.