The labour-saving bicycle doesn't change the structure of original bicycle. The bicycle saddle is fixed on a main force rod, and after having been equipped with a spring the main force rod slips into the seat tube. The main force rod can be up-down moved in the seat tube by means of compression and extension of the spring. Another end of the main force rod can transfer the force to the chain wheel fixed on the pedal axle via a link mechanism. The chain wheel is connected with the left and right flywheels of the rear wheel by means of its left and right drawbars. ADVANTAGE-has no need of additional power, pedalling; utilizes the gravity force of human self-body to drive wheel to make it rotate forwards. |