Variable speed drive for a bicycle

Abstract

Abstract The invention is directed to a variable speed drive for a bicycle. In accordance with the invention there is provided a variable diameter driving mechanism rotatably mounted on the bicycle, the mechanism including a mounting plate having a plurality of radial tracks therein. A plurality of movable sheave elements are each mounted in one of the tracks, each sheave element having a releasable retaining means which normally retains it at a substantially fixed radial position in its track. A flexible driving means, preferably a V-belt, is partially wrapped around the driving mechanism and engages different adjacent ones of the sheave elements depending on the rotational orientation of the driving mechanism. A gate or interposing means is positioned to sequentially coact with the non-engaged sheave elements and is operative, under manual control, to release the retaining means of a sheave element to allow radial motion of the sheave element. Also, means are provided for applying a radial bias to the released sheave elements. In the preferred embodiment of the invention, the gate means is movable radially under manual control and coacts with the sheave elements only when the gate means is at a different radial reference than the sheave elements. In this preferred embodiment, the radial tracks are radial slots in the plate and each sheave has two symmetrical arcuate belt-carrying surfaces which protrude from opposite sides of the mounting plate. Accordingly, a pair of drive belts can be utilized on opposite sides of the mounting plate for a balanced drive. Further, in this preferred embodiment a pair of variable diameter driving mechanisms, as defined, are employed, one at the front pedal drive and the second at the rear wheel drive. Means are provided for varying the diameters of these two mechanisms in opposite relationship under manual control.

Inventors

• 👤 Hamlin Leonard

Bibliographic Details