Bicycle front derailleur with a variable actuation ratio

摘要

A front derailleur comprises a base member structured to be attached to a bicycle frame member, a chain guide operatively connected to the base member, and an actuation mechanism coupled to the base member and to the chain guide for moving the chain guide relative to the base member between a first position corresponding to a location for positioning a chain on a first sprocket and a second position corresponding to a location for positioning the chain on a second sprocket. The actuation mechanism is configured so that an actuation ratio of the derailleur when the chain guide is located in the first position is greater than or equal to 1.5 times the actuation ratio when the chain guide is located in the second position.

主权项

1. A front derailleur comprising:
a base member structured to be attached to a bicycle frame member; a chain guide operatively connected to the base member; and an actuation mechanism coupled to the base member and to the chain guide for moving the chain guide relative to the base member between a first position corresponding to a location for positioning a chain on a first sprocket and a second position corresponding to a location for positioning the chain on a second sprocket; wherein the actuation mechanism is configured so that an actuation ratio of the derailleur when the chain guide is located in the first position is greater than or equal to 1.5 times the actuation ratio when the chain guide is located in the second position so that the force required to operate the derailleur when the chain guide is located in the first position is greater than the force required to operate the derailleur when the chain guide is located in the second position; wherein the actuation ratio is greater than 1.5 when the chain guide is located in the first position; and wherein the actuation ratio is less than 3.5 when the chain guide is located in the first position.