US 5,197,927 AGranted

Bicycle derailleur cable actuating system

AssigneeSram, LLC

InventorsSam H. Patterson, John D. Cheever, Jeffery M. Shupe

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Abstract

A bicycle gear shifting system having rotatable front and rear handgrip shift actuators operatively associated with control cables for shifting respective front and rear derailleur mechanisms. In some forms of the invention the control cable is directly actuated by the handgrip rotator, while in other forms the shifter rotator drives a separate "jack spool" which in turn actuates the control cable. A cam on either the handgrip rotator or the jack spool is configured so as to substantially compensate for increasing force of the derailleur return spring during down-shifting. Compensation is provided in the shift actuators of the invention for various lost motions in the derailleur shifting mechanisms and control cable systems. The shift actuators of the invention also provide overshift movement of the derailleur mechanisms in the down-shifting direction so as to overshift the bicycle chain a sufficient amount beyond the destination derailleur sprocket so that the chain will approach the destination sprocket in the same direction as it would in the up-shifting direction. The shift actuators of the invention also provide equalization for the higher derailleur return spring force during down-shifting than during up-shifting, and allow fine-tuning to avoid chain rasp, which is particularly important for "cross-over" riding.

Claims108

Dependent claims

A bicycle gear shifting system, which comprises:

derailleur shifting means having return spring means operatively associated with the rear wheel of the bicycle;
handgrip shift actuator means mounted on the handlebar of the bicycle;
said shift actuator means comprising manually actuated shifter rotator means rotatable about a first axis generally coaxial of the handlebar,
said rotator means being selectively rotatable one way in a down-shifting direction and the opposite way in an up-shifting direction;
said shift actuator means further comprising jack spool means rotatable about a second axis that is angularly offset from said first axis;
control cable means having one end secured to said jack spool means and the other end operatively connected to said derailleur shifting means, said control cable means being biased toward said derailleur shifting means by said return spring means;
said jack spool means being rotatable one way in a down-shifting direction in which said jack spool means pulls said control cable means for down-shifting said derailleur shifting means, and the opposite way in an up-shifting direction in which said jack spool means releases said control cable means for up-shifting said derailleur shifting means;
and
an operative connection between said rotator means and said jack spool means such that down-shifting rotation of said rotator means will cause synchronous down-shifting rotation of said jack spool means, and up-shifting rotation of said rotator means will cause synchronous up-shifting rotation of said jack spool means.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/853,442Filed 18 Mar 1992 · continuation in part
Priority: 20 Mar 1991
Granted: 30 Mar 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

B62K 23/04
Hand actuated: twist grips
B62M 9/1248
Mechanisms for shifting laterally: characterised by the use of biasing means, e.g. springs; Arrangements thereof
B62M 9/127
Rear derailleurs: mounting or guiding of cables
B62M 9/131
The chain, belt, or the like being laterally shiftable , e.g. using a rear derailleur: front derailleurs