Bicycle wheel travel path for selectively applying chainstay lengthening effect and apparatus for providing same
AssigneeOutland Design Techologies, Inc.
InventorsJames B. Klassen, Jamie W. Calon
Life of this patent
Estimating the term…
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 in 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.
Claims22
A compressible rear suspension for a bicycle, comprising
- a chain drive in which a chainstay length is the distance in the rearward direction from the axis of a pedal-operated drive sprocket to the axis of a rear wheel hub, which is represented by a variable value CSL;
- and
- means for moving said rear wheel in a generally upward direction along a controlled wheel travel path in response to compression of said suspension, in which the position of said hub along said path from a predetermined starting point at which said suspension is extended is represented by a variable value D which increases with increasing compression of said suspension, said controlled wheel travel path comprising:
- a preferred pedaling position at a predetermined position Dp which is located along said wheel travel path;
- a lower curve segment extending generally below said position Dp in which there is an increasing rate of chainstay lengthening with increasing compression of said suspension system, such that the first derivative relationship ##EQU13## is a curve having a generally positive slope, so that the second derivative relationship ##EQU14## is generally positive;
- and an upwardly and forwardly curved upper curve segment extending generally above said position Dp in which there is a decreasing rate of chainstay lengthening with increasing compression of said suspension system, such that the first derivative relationship ##EQU15## is a curve having a generally negative slope, so that the second derivative relationship ##EQU16## is generally negative.
A bicycle comprising:
- a chain drive, in which a chainstay length is the distance in the rearward direction from the axis of a pedal-operated drive sprocket to the axis of a rear wheel hub, which is represented by a variable value CSL;
- and
- a compressible rear suspension having means for moving said hub along a controlled wheel travel path as said suspension is compressed, in which the position of said hub along said path from a predetermined starting point at which said suspension is extended is represented by a variable value D which increases with increased compression of said rear suspension, said controlled wheel travel path comprising:
- a preferred pedaling position at a predetermined position Dp which is located along said wheel travel path;
- a lower curve segment extending generally below said position Dp in which there is an increasing rate of chainstay lengthening with increasing compression of said suspension, such that the first derivative relationship ##EQU17## is a curve having a generally positive slope, so that the second derivative relationship ##EQU18## is generally positive;
- and an upwardly and forwardly curved upper curve segment extending generally above said position Dp in which there is a decreasing rate of chainstay lengthening with increasing compression of said suspension system, such that the first derivative relationship ##EQU19## is a curve having a generally negative slope, so that the second derivative relationship ##EQU20## is generally negative.
Dependencies are inferred from the claim text.