Bicycle front derailleur

Abstract

A bicycle front derailleur is configured to facilitate a chain returning to a sprocket during an upshifting operation if the chain drops off. The front derailleur basically has a fixed member, a chain guide and a moving mechanism. The fixed member can be fastened to a bicycle. The chain guide has an inner plate and an outer plate with a gap between the outer plate and the inner plate. The chain guide guides the chain between itself and the inner plate. The chain guide is free to move with respect to the fixed member. The inner plate has a first protruding part that protrudes toward the outer plate on the rear end, which is the chain entry side. The moving mechanism is a mechanism that is used to cause the chain guide to move.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG. 1 is a right side elevational view of a bicycle equipped with a front derailleur in accordance with a first embodiment of the present invention;

FIG. 2 is a perspective view of the front derailleur in accordance with the first embodiment of the present invention;

FIG. 3 is a rear perspective view of the back surface of a chain guide in accordance with the first embodiment of the present invention;

FIG. 4 is an inside perspective view of the side surface of the chain guide that faces the bicycle frame in accordance with the first embodiment of the present invention;

FIG. 5 is a front elevational view of the chain guide in accordance with the first embodiment of the present invention;

FIG. 6 is a simplified, side elevational view showing a chain switching operation during downshifting using the chain guide of the first embodiment of the present invention;

FIG. 7 is a simplified, side elevational view showing a chain in the chain dropping state and in a chain returned state;

FIG. 8 is a perspective view, similar to FIG. 2, of the front derailleur in accordance with a second embodiment of the present invention;

FIG. 9 is an inside perspective view, similar to FIG. 4, of the side surface of the chain guide that faces the bicycle frame in accordance with a third embodiment of the present invention;

FIG. 10 is an enlarged, partial rear perspective view of a rear portion of the chain guide in accordance with a third embodiment of the present invention;

FIG. 11 is a top plan view of the rear part of a rear portion of the chain guide in accordance with a third embodiment of the present invention; and

FIG. 12 is a top plan view, similar to FIG. 11, of a rear portion of a chain guide in accordance with a fourth embodiment of the present invention.

Claims

1. A bicycle front derailleur comprising: a fixed member configured and arranged to be fixedly attached to bicycle;a chain guide configured to move between a retracted position and an extended position relative to the fixing base, the chain guide including an inside member and an outside member defining a chain receiving slot to guide a chain, the inside member has a rear end with a protruding part disposed on a chain entry side of the chain receiving slot, and protruding towards the outside member; anda moving mechanism coupled between the fixed member and the chain guide to move the chain guide between the retracted position and the extended position.

2. The bicycle front derailleur according to claim 1, wherein the inside member further has a first tapered part tapering gradually toward the first protruding part from a chain exit side of the chain receiving slot that is opposite from the chain entry side.

3. The bicycle front derailleur according to claim 2, wherein the inside member has a chain shifting part extending from the chain entry side toward the chain exit side to provided for shifting of the chain.

4. The bicycle front derailleur according to claim 2, wherein the inside member has a first edge part facing generally towards the chain entry side and a second edge part on a chain withdrawal side spaced from the chain entry side toward the chain exit side; andthe first protruding part is at least partially disposed in an area of the chain entry side that is adjacent the second edge part.

5. The bicycle front derailleur according to claim 1, wherein the first protruding part protrudes toward the outside member in a range of one to two millimeters relative an adjacent part of the inside member.

6. The bicycle front derailleur according to claim 1, wherein the inside and outside members are formed as a one-piece member with a bolt member connecting the inside and outside members at the chain entry side.

7. The bicycle front derailleur according to claim 6, further comprising a washer member fastened to the chain entry side by the bolt member, with the washer member being arranged to fill a difference in level between the first protruding part and a connecting part disposed between the inside and outside members.

8. The bicycle front derailleur according to claim 6, wherein the first protruding part includes a spacer fastened by the bolt member.

9. The bicycle front derailleur according to claim 1, wherein the inside member is a press-formed, metallic plate, with the first protruding part being a part of the press-formed, metallic plate that constitutes the inside member.

10. The bicycle front derailleur according to claim 3, wherein the inside member has a first edge part facing generally towards the chain entry side and a second edge part on a chain withdrawal side spaced from the chain entry side toward the chain exit side; andthe first protruding part is at least partially disposed in an area of the chain entry side that is adjacent the second edge part.

11. The bicycle front derailleur according to claim 2, wherein the first protruding part protrudes toward the outside member in a range of one to two millimeters relative an adjacent part of the inside member.

12. The bicycle front derailleur according to claim 2, wherein the inside and outside members are formed as a one-piece member with a bolt member connecting the inside and outside members at the chain entry side.

13. The bicycle front derailleur according to claim 12, further comprising a washer member fastened to the chain entry side by the bolt member, with the washer member being arranged to fill a difference in level between the first protruding part and a connecting part disposed between the inside and outside members.

14. The bicycle front derailleur according to claim 12, wherein the first protruding part includes a spacer fastened by the bolt member.

15. The bicycle front derailleur according to claim 2, wherein the inside member is a press-formed, metallic plate, with the first protruding part being a part of the press-formed, metallic plate that constitutes the inside member.

16. The bicycle front derailleur according to claim 3, wherein the inside and outside members are formed as a one-piece member with a bolt member connecting the inside and outside members at the chain entry side.

17. The bicycle front derailleur according to claim 16, further comprising a washer member fastened to the chain entry side by the bolt member, with the washer member being arranged to fill a difference in level between the first protruding part and a connecting part disposed between the inside and outside members.

18. The bicycle front derailleur according to claim 16, wherein the first protruding part includes a spacer fastened by the bolt member.

19. The bicycle front derailleur according to claim 3, wherein the inside member is a press-formed, metallic plate, with the first protruding part being a part of the press-formed, metallic plate that constitutes the inside member.