Shimano Inc.

Yoshiaki Nankou

Nobuyoshi Fujii

Kazufumi Yamamoto

Atsuhiro Emura

A bicycle structure is provided with a crankset and a front derailleur. The crankset includes a plurality of chain rings, with a largest chain ring of the plurality of chain rings having a plurality of teeth with teeth bottoms interposed between adjacent ones of the teeth. The front derailleur includes a chain guide having a chain guide slot partially defined by a first chain engagement surface with a protruding part that protrudes outwardly from the first chain engagement surface into the chain guide slot. The protruding part is located away from the teeth bottoms of the largest chain ring in a radial outside direction of the largest chain ring by a prescribed distance in a range from eight millimeters to sixteen millimeters.

Bicycle structure

A front derailleur chain detachment prevention member is provided that can be easily removed from a front derailleur. The front derailleur chain detachment prevention member is removably mounted on a front derailleur, and has elasticity. The front derailleur chain detachment prevention member is provided with a mounting part, a connecting part, and a regulating part. The mounting part is removably attached to an inner plate of a chain guide. The connecting part extends forward from the mounting part along the inner plate. The regulating part is disposed at a tip of the connecting part, and projects from the inner plate toward an outer plate of the front derailleur.

Front derailleur chain detachment prevention member

A bicycle front derailleur includes a fixed member, a chain guide and a linkage assembly. The fixed member includes a fixing body and a projection part fixedly coupled together. The fixing body includes a fastening portion with a seat tube reference plane that aligns with a longitudinal center axis of a seat tube when coupled thereto. The projection part has a projecting surface offset axially from the fixing body toward a smallest front chain ring of a bicycle front crankset. The projecting surface has an overall vertical height lying substantially in a single plane measured in a direction parallel to the seat tube reference plane that is greater than 10 millimeters in an area between the seat tube reference plane and 23 millimeters measured perpendicularly and forwardly from the seat tube reference plane.

Bicycle front derailleur

A bicycle front derailleur includes a fixed member, a chain guide, a linkage assembly and an adjustable mounting fixture. The fixed member includes a frame mounting portion having at least one frame mounting hole and a linkage support portion. The linkage assembly is coupled between the linkage support portion and the chain guide in order to move the chain guide between the retracted position and the extended position. The mounting fixture is adjustably coupled to the fixed member. The mounting fixture including at least one frame fastener disposed in the frame mounting hole, a pair of first washer members disposed on a first side of the frame mounting portion and a pair of second washer members disposed on a second side of the frame mounting portion with the frame fastener extending through the first and second washer members.

A front derailleur has a base member adapted to be coupled to a bicycle frame, a chain guide, first and second pivotal links coupled between the base member and the chain guide, and a biasing member normally biasing the chain guide toward a first position. The biasing member is disposed on a pivot axis pivotally coupling the first link to the chain guide to be at least partially located in front of the part of the first link coupled to the base member. The first link is preferably an inner link located closer to the frame than the second link. Preferably, portions of the first link are at least partially offset due to a transitional portion arranged between them. Preferably, the second link includes a cable attachment portion and a pair of axially spaced mounting elements pivotally coupled to ends of an attachment element of the base member.

A protective plate for attachment to a bicycle frame for guiding a chain includes a plate body having a first side for facing laterally toward the bicycle frame, a second side for facing laterally away from the bicycle frame, a lower portion, and an upper portion. The lower portion of the first side of the plate body is structured to align with a bottom bracket of the bicycle, and a positioning abutment member is disposed on the upper portion of the first side of the support body. An upper surface of the positioning abutment member forms a positioning abutment for positioning a front derailleur to the bicycle frame. Additionally, a chain guiding abutment may be formed on the upper portion of the second side of the support body for guiding the chain as the chain shifts from a larger chainring to a smaller chainring.

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Sakai, Japan

Yoshiaki Nankou