Abstract: The fundamental principle of this invention is based on the fact that the moment of force or torque is equal to the product of a force and a distance through which the force acts from the fulcrum. The pedal of a bicycle comprises a pair of freely rotatable treads together with a pair of inner and outer plates around a spindle connected to a crank, the spindle, a center tube covering the spindle, and minor parts. The force of man's leg onto the pedal per unit time can be conserved or increased by securing one of the rotatable treads to the spindle by means of a one-way clutch means provided in the space between center tube and spindle in order to enlarge the distance from the fulcrum to the point of action of the force.

Abstract: A tubular ferrous blank, the starting material of the invention, set in a sectional forming die having a concave inner surface corresponding to a desired contour is subjected to the oil hydraulic bulge forming process in a press machine provided with a vertically movable ram and a pair of horizontally opposed movable rams to form two identical, but different oriented protuberant components in one embodiment of the invention, and one relatively big protuberant component and relatively small twin parallel protuberant components in another embodiment, each of the components being axis-asymmetrically formed, and again subjected to a mechanical bulge forming step by the aid of two opposed mandrels affixed to the horizontal rams inserted forcibly into the thus formed tubular blank to form a cut wave joggled design or pattern on the exterior surface of the tubular blank.