Bicycle wheel travel path for selectively applying chainstay lengthening effect and apparatus for providing same

Abstract

A rear suspension system for a bicycle. The system directs the rear wheel along a predetermined, S-shaped path as the suspension is compressed. The path is configured to provide a chainstay lengthening effect only at those points where this is needed to counterbalance the pedal inputs of the rider; at those points on the wheel travel path where there is a chainstay lengthening effect, the chain tension which results from the pedal inputs exerts a downward force on the rear wheel, preventing unwanted compression of the suspension. The system employs a dual eccentric crank mechanism mounted adjacent the bottom bracket shell to provide the desired control characteristics.

Description

[0001]This application is a continuation-in-part of U.S. Ser. No. 08 / 724,303, filed Sep. 19, 1996, abandoned Apr. 22, 1999; which is a continuation-in-part of U.S. Ser. No. 08 / 558,162, filed Nov. 15, 1995 (U.S. Pat. No. 5,628,524, issued May 13, 1997); which is a continuation-in-part of U.S. Ser. No. 08 / 377,931, filed Jan. 25, 1995 (U.S. Pat. No. 5,553,881, issued Sep. 10, 1996). This application claims benefit of provisional application Ser. No. 60 / 040,702 filed Mar. 13, 1997.FIELD OF THE INVENTION[0002]The present invention relates generally to bicycles, and more particularly to a rear suspension system which provides efficient energy transmission but still provides compliant suspension action when the bicycle is ridden over rough terrain.BACKGROUND OF THE INVENTION[0003]Shock absorbing rear suspensions for bicycles are known. In general, however, these have not proven entirely satisfactory in practice.[0004]In most rear suspension assemblies, the rear axle pivots about a single p...

AI Technical Summary

Benefits of technology

[0006]The present invention has solved the problems cited above. Broadly, this is a bicycle comprising: a chain drive in which the distance from the axis of a drive sprocket to the axis of a rear wheel hub is represented by a variable value CSL; and a compressible rear suspension having a linkage for moving the hub along a controlled wheel travel path as the suspension is compressed, the controlled wheel travel path having an arc radius which is greater towards a lower end of the path and smaller towards an upper end of the path.

Problems solved by technology

In general, however, these have not proven entirely satisfactory in practice.

In this respect, the spring / damper assembly of the rear suspension is affected by the pedal force and some of the rider's energy is needlessly wasted.

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