US 4,406,643 AGranted

Derailleur for a bicycle

AssigneeShimano Industrial Company Limited

InventorKeizo Shimano

Life of this patent

Estimating the term…

Loading patent…

Abstract

A derailleur for a bicycle, which is so constructed that a movable member is supported to a base member through two linkage members, a changeover frame having two pulleys carrying thereon a driving chain is pivoted to the movable member, and a tension spring is interposed between the movable member and the changeover frame, so that the tension spring exerts tension on the driving chain, said changeover frame being subjected to resistance against its swinging motion in a direction opposite to the working direction of the tension spring, thereby swinging the changeover frame easily in the direction of working of the changeover frame, while, requiring more force in the reverse direction to the working thereof, thereby making swinging of the changeover frame in the working direction of the tension spring easy and more difficult in the swinging motion direction opposite to the working direction of the spring.

Claims8

Dependent claims

A derailleur for a bicycle which changes a driving chain to a desired one of a plurality of chain gears, said derailleur comprising:

(a) a derailleur body comprising a base member, two linkage members pivoted to said base member, and a movable member pivoted to said linkage members;
(b) a chain changeover frame having two pulleys and being supported pivotally to said movable member;
(c) a tension spring interposed between said changeover frame and said movable member for exerting tension on said driving chain;
(d) a resistance applying means connected between said changeover frame and said movable member for applying a resistance to the swinging movement of said changeover frame relative to said movable member only when said changeover frame swings in a direction opposite to a working direction of said tension spring acting on said changeover frame, so that said changeover frame swings in said working direction against less applied resistance than that existing when said changeover frame swings in a direction opposite to said working direction.

1 more element

Dependencies are inferred from the claim text.