Transmission for a bicycle pedal

#This invention relates to a bicycle pedal gearshift for enabling a change in speed change of a bicycle by adjusting the ratio of gyration of a pedal.

#The driving gear of a bicycle generally includes a front wheel, a pedal connected to the wheel, a rear wheel and a chain connecting the two wheels.

#The bicycle may be equipped with various gearshifts. The torque and speed of revolution to turn the pedals, and the rotational speed of the front and rear wheels may be adjusted to be suitable for a user by adjusting the gearshift.

#FIG. 1 is an exploded perspective view showing the bicycle pedal gearshift in accordance with a first embodiment of the invention;

#FIG. 2 is a perspective view the bicycle pedal gearshift of FIG. 1, assembled;

#FIG. 3 is the sectional view taken through line A–A′ of FIG. 2;

#Referring now to the drawings, a bicycle pedal gearshift according the invention is equipped with a fixed axle 11, 41, 52 having one end adapted to be connected to the wheel of bicycle, and a guide axle 17, 58 with a lower section in the form of a column having a square cross section, an upper connection section 21, 60 adapted to be connected to the other end of the fixed axle 11, 41, 52, and a central section having a male screw section 23, 62. A crank 10, 40, 51 includes a connector arrangement for being installed between the fixed axle 11, 41, 52 and guide axle 16, 43, 57 to fix and support the fixed axle 11, 41, 52 and guide axle 16, 43, 57. The bicycle pedal gearshift has a nut 27 adapted to be threaded along the male screw section 23,62 on the guide axle 16,43,57. A limit bolt 29 can be fixed and connected to the lower portion of guide axle 16,43,57. A slider 30 has a square bore 31 formed in its center for being translated along the guide section 17,58 on the guide axle 16,43,57. A blind hole 32 is formed inside the bore on one side of the slider 30, on the bottom of which there is also formed a semicircular limit groove 33 for receiving the head of the limit bolt 29 so that it can be stably supported. The slider 30,65 is equipped with a pedal axle allowing the pedal 35,69 to be connected to the side of the slider opposite the side on which the ball 37 is mounted. The ball 37 can be selectively received in an upper supporting hole 19 and a lower supporting hole 20 on the side of the guide axle 16,43,57 as the slider 30,65 is translated under pressure from a spring 36 inserted in the blind hole 32 in the slider 30,65.

#When the pedal 35, 69 is lifted by a foot in a vertical direction, or pulled in a horizontal direction, positioning the crank 10, 40, 51 vertically or horizontally, the slider 30, 65 is translated along the guide section 17, 58 of guide axle 16, 43, 57 and the ball 37 is released from the bottom supporting hole 20. As the slider 30, 65 moves toward nut 27 during the continual rotation of the pedal 35, 69, the ball 37 is received in the upper supporting hole 19 and the translated pedal 35, 69 is supported there. Hence, easy adjustment of the ratio of gyration of the pedal is enabled and quick and easy speed change is allowed. Also, adjusting the length of crank 10, 40, 51 by the above described connector arrangement is possible, and the range of speed change and utilization of space may be optimized by the allowable folding of the pedal with the crank inline upon storage of and moving the bicycle.

#The detailed characteristics and advantages of the invention will be made more clear by the following descriptions referring to the drawings.