Rear derailleur
AssigneeShimano Inc.
InventorMasashi Nagano
Life of this patent
Estimating the term…
Abstract
It is the problem to provide a rear derailleur having structure in which even when the chain has been looped over a chain wheel of major diameter, the tension sprocket wheel does not come so closer to the ground to thereby reduce accidents of a violent fall or trouble. Further, it is the problem to facilitate detachment and attachment of the wheel, and to provide a rear derailleur having a wide application range to wheel size. To solve these problems, the guide arm and the tension arm are capable of rocking around the guide arm rocking axis and the tension arm rocking axis which are different from each other, and these arms are rocked independently of each other, and the distance between the guide sprocket wheel and the tension sprocket wheel varies with the speed variation state.
Claims16
A rear derailleur for a bicycle, comprising:
- a base member having an installation area for installing to a bicycle body;
- a parallel rocking member;
- a pair of parallel cranks interposed between said base member and said parallel rocking member, for constituting an actual parallel link mechanism together with those members;
- a guide arm provided on said parallel rocking member so as to be freely rockable around a first rocking axis parallel with a rear wheel axle axis;
- a guide sprocket provided on said guide arm so as to be freely rotatable around an axis parallel with said first rocking axis;
- a tension arm provided on said parallel rocking member so as to be rockable around a second rocking axis parallel with said rear wheel axle axis;
- a tension sprocket provided on said tension arm so as to be freely rotatable around a parallel axis with said second rocking axis;
- and
- a biasing spring provided between said tension arm and said parallel rocking member in order to bias said tension sprocket toward the rear of said bicycle.
Dependencies are inferred from the claim text.