Abstract: A bicycle in which the frame is so constructed that the pedal crank is displaced forwardly of the center of the back wheel by a distance equal to at least twice the radius of the back wheel, and the rear frame member has a length equal to at least twice the radius of the back wheel, and the steering column housing is slanted at an angle of between 62.degree. and 58.degree. to the horizontal, and the saddle support column has a length equal to between 1.2 and 1.4 times the radius of the back wheel, and terminates at an upper end located approximately perpendicularly above the intersection between the rear frame support, and the periphery of the back wheel, and the saddle support column is slanted at a lesser angle than the steering column housing of between 40.degree. and 44.degree. to the horizontal, and including a back rest extending upwardly behind the saddle.

Abstract: A rotary machine particularly intended for use as a pump comprises a two-lobe lenticular rotor rotatably disposed within a pump chamber defined by an annular wall with an inner surface having at least in part a cardioidal configuration. A rectangular drive plate on a shaft is disposed within an elongated drive slot in the rotor while a circular guide disc fixed on an end wall of the pump casing extends into a second elongated guide slot in the rotor. The second guide slot is perpendicular to the first slot so that, during operation, the rotor effectively reciprocates and rotates relative to the guide disc. If desired, two such circular guide discs can be provided, one on each end wall of the pump casing, for reciprocation and rotation relative to two such second guide slots in opposite faces of the rotor.