The present invention relates to a bicycle power generating arrangement, which comprises a rack mounted on the frame of a bicycle to hold wheel means on the ground, and a dynamo coupled to the wheel means and actuated to generate electricity upon running of the bicycle.
Various structures of dynamos for bicycle have been disclosed. FIG. 1 shows a dynamo installed in the frame of a bicycle and pressed on the tire of the front wheel according to the prior art. When rotating the front wheel of the bicycle, the dynamo is driven to generate electricity. This structure of dynamo is not satisfactory in function because much resisting force is produced against the pedaling effort of the bicycle rider. The resisting force comes from two sources. One source of the resisting force is the spring means, which forces the rotor of the dynamo against the tire of the front wheel of the bicycle. Because the spring means imparts a pressure to the dynamo against the tire of the front wheel in direction perpendicular to the steering direction of the bicycle, much resisting force is produced against rotation of the front wheel.
The other source of the resisting force is the force required to actuate the dynamo. The output capacity of a dynamo for bicycle may be 6V, 3 W. The power of 3 W is not great. However, because the position of the driving power for the dynamo is at the lateral side of the tire of the front wheel of the bicycle, the arm of force is long, and much resistance is produced when rotating the rotor of the dynamo. Another drawback of this structure of dynamo is that the tire of the front wheel of the bicycle wears quickly with use. Because the rotor of the dynamo rubs on the tire of the front wheel of the bicycle during rotation of the front wheel of the bicycle, the tire of the front wheel of the bicycle wears quickly. Furthermore, because the rotor of the dynamo rubs on the tire of the front wheel of the bicycle, the front wheel of the bicycle tends to be forced out of alignment, causing the bicycle to vibrate during running. FIG. 2 illustrates another structure of dynamo according to the prior art. This structure of dynamo is installed in the spokes of the front wheel of the bicycle, and actuated to generate electricity upon running of the bicycle. This structure of dynamo also has drawbacks. Because the dynamo is not detachable, it works upon running of the bicycle. In the daytime, it is not necessary to provide electricity to the lamp of the bicycle, however the dynamo still works. Further, because the revolving speed of the dynamo is equal to the revolving speed of the wheels of the bicycle, the intensity of magnetic field or the length of the enamel wire of the dynamo must be relatively increased so that sufficient output voltage can be obtained (e=Blv, B=intensity of magnetic field, l=length of enamel wire, v=velocity). However, increasing the intensity of magnetic field or the length of the enamel wire of the dynamo relatively increases the manufacturing cost of the dynamo and its dimension.
The present invention has been accomplished to provide a bicycle power generating arrangement, which eliminates the aforesaid drawbacks. According to one aspect of the present invention, the bicycle power generating arrangement comprises a dynamo, and wheel means dragged from the frame of the bicycle and rotated over the ground to actuate the dynamo upon running of the bicycle. According to another aspect of the present invention, lock means is provided and adapted to lock the wheel means in a lifted position, preventing the wheel means from rotation during running of the bicycle.