Front derailleur for a bicycle

Patent metadata

Field	Value
Publication number	US-10676154-B2
Application number	US-201815892814-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Feb 13, 2017
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A bicycle front derailleur that is movable between shift positions in association with an indexer. The inner mechanical end stop is adjusted at the first indexing position so there is no loosening of the control cable in the last downward gearshifting operation, with the benefit of an immediate and rapid response in the first upward gearshifting operation. The outer end stop is adjusted to interrupt the rotation of the cable-winding bush before it reaches the last indexing position. This pair of mechanical end stops limits the excursion of the derailleur to prevent it being able to shift the chain too much towards the frame or too much away from the frame, which ensures that the chain is not shifted beyond the gears.

First claim

What is claimed is:

1. A front derailleur for a bicycle, comprising:
a movable body, provided with a chain guide configured to interact with a transmission chain of the bicycle and movable between a plurality of positions comprised between an inner position and an outer position;
a fixed body, adapted for being fixed to a part of frame of the bicycle;
an outer connection element hinged to the fixed body about a first articulation axis and hinged to the movable body about a second articulation axis;
an inner connection element hinged to the fixed body about a third articulation axis and hinged to the movable body about a fourth articulation axis;
a return member active between the movable body and the inner connection element to push said chain guide in said inner position; and
an actuation arm hinged to the fixed body about said first articulation axis and comprising a fastener for a control cable arranged to move away from the first articulation axis on an opposite side with respect to the second articulation axis;
said actuation arm and said outer connection element being rigidly connected to make a rocker arm when a force exerted on said fastener is such as to determine a movement of the chain guide between the inner position and the outer position, said actuation arm rotating with respect to said outer connection element when a force exerted on said fastener is greater than a force necessary to hold the chain guide in the outer position.

2. The front derailleur according to claim 1 , wherein said fixed body, said movable body, said inner connection element and said outer connection element define an articulated quadrilateral deformable by said return member to move said chain guide from the outer position to the inner position and deformable by said actuation arm to move said chain guide from the inner position to the outer position.

3. The front derailleur according to claim 2 further comprising an elastic member active between said outer connection element and said actuation arm, said elastic member elastically yielding when a force applied to said actuation arm is greater than a force necessary to deform said articulated quadrilateral to take the chain guide into the outer position.

4. The front derailleur according to claim 3 , wherein said elastic member comprises a torsion spring arranged at said second articulation axis.

5. The front derailleur according to claim 4 , wherein said torsion spring of the elastic member is mounted with a torsional preload between the actuation arm and the outer connection element; said preload of the torsion spring applying a force on said actuation arm that tends to rotate it about the first articulation axis in an opposite angular direction with respect to the rotation of the first actuation arm about the first articulation axis when subjected to a traction force of the control cable.

6. The front derailleur according to claim 5 , wherein said outer connection element comprises a shoulder engageable in abutment by a protrusion of the actuation arm; said shoulder and said protrusion being arranged on the opposite side to the first articulation axis with respect to said torsional spring.

7. The front derailleur according to claim 4 , wherein said return member comprises a torsion return spring; a torque to be applied to the torsion spring of the elastic member to cause a rotation of the actuation arm with respect to the outer connection element is greater than a torque applied to the torsion return spring to cause a rotation of the movable body with respect to the inner connection element.

8. The front derailleur according to claim 4 further comprising an articulation pin arranged at said first articulation axis, said outer connection element and said actuation arm being crossed by said articulation pin; and said actuation arm comprising an appendage that extends away from said articulation pin towards said second articulation axis.

9. The front derailleur according to claim 8 , wherein said torsion spring of the elastic member comprises a first end abutting on said appendage of the actuation arm and a second end abutting in a seat of the outer connection element.

10. The front derailleur according to claim 7 , wherein said torsion spring of the elastic member is mounted with a torsional preload between the actuation arm and the outer connection element; said torsional preload being greater than a torsional load to be applied to the torsion return spring of the return member to move the chain guide into outer position.

11. The front derailleur according to claim 8 , wherein said appendage of the actuation arm comprises a projection facing towards said outer connection element; said projection defining an end stop block for the rotation of the actuation arm with respect to the outer connection element.

12. The front derailleur according to claim 1 , wherein a force applied to said fastener of the actuation arm to move the chain guide from the inner position to the outer position is contained in a plane perpendicular to the first articulation axis.

13. The front derailleur according to claim 1 , wherein a distance between the fastener of the actuation arm and the first articulation axis remains constant during the rotation of the actuation arm with respect to the outer connection element.

14. The front derailleur according to claim 5 , wherein said return member comprises a torsional return spring; a torque to be applied to the torsion spring of the elastic member to cause a rotation of the actuation arm with respect to the outer connection element is greater than a torque applied to the torsional return spring to cause a rotation of the movable body with respect to the inner connection element.

15. The front derailleur according to claim 14 further comprising an articulation pin arranged at said first articulation axis, said outer connection element and said actuation arm being crossed by said articulation pin; and said actuation arm comprising an appendage that extends away from said articulation pin towards said second articulation axis.

16. The front derailleur according to claim 6 , wherein said return member comprises a torsional return spring; a torque to be applied to the torsion spring of the elastic member to cause a rotation of the actuation arm with respect to the outer connection element is greater than a torque applied to the torsional return spring to cause a rotation of the movable body with respect to the inner connection element.

17. The front derailleur according to claim 16 further comprising an articulation pin arranged at said first articulation axis, said outer connection element and said actuation arm being crossed by said articulation pin; and said actuation arm comprising an appendage that extends away from said articulation pin towards said second articulation axis.

18. The front derailleur according to claim 2 , wherein a force applied to said fastener of the actuation arm to move the chain guide from the inner position to the outer position is contained in a plane perpendicular to the first articulation axis.

19. The front derailleur according to claim 18 , wherein a distance between the fastener of the actuation arm and the first articulation axis remains constant during the rotation of the actuation arm with respect to the outer connection element.

20. The front derailleur according to claim 2 , wherein a distance between the fastener of the actuation arm and the first articulation axis remains constant during the rotation of the actuation arm with respect

Assignees

• Campagnolo Srl

Inventors

• Minto Marco

Classifications

• B62M9/135

  Mounting the derailleur on the frame · CPC title

• B62M9/1348

  characterised by the use of biasing means, e.g. springs; Arrangements thereof · CPC title

• B62M9/1342 Primary

  characterised by the linkage mechanisms · CPC title

• B62M9/131 Primary

  Front derailleurs · CPC title

• B62M25/02

  with mechanical transmitting systems, e.g. cables, levers · CPC title