Electrically operated derailleur that re-engages a disengaged derailleur force overload clutch

1. An apparatus for controlling a derailleur, wherein the derailleur includes a motor that drives a drive member, a driven member driven by the drive member, and a clutch having a first element that disengages from a second element when substantial resistance exists in a power transmission path between the drive member and the driven member, wherein the apparatus for controlling the derailleur comprises:

a re-engage command receiving circuit that receives a re-engage command signal to re-engage the first element with the second element when the first element is disengaged from the second element; and

a re-engagement circuit that re-engages the first element with the second element in response to the re-engage command signal;

wherein the re-engagement circuit comprises a re-engagement detecting circuit that detects when the first element re-engages with the second element.

2. The apparatus according to claim 1 wherein the re-engagement circuit provides a motor drive signal that causes the motor to move the drive member in a direction so that the first element re-engages the second element.

3. The apparatus according to claim 2 wherein the motor drive signal causes the motor to move the drive member in a direction towards and end of a range of motion of the drive member.

4. The apparatus according to claim 3 wherein the motor drive signal causes the motor to move the drive member in a direction towards a position corresponding to a top gear position of the derailleur.

5. The apparatus according to claim 3 wherein the motor drive signal causes the motor to move the drive member to the end of the range of motion of the drive member and then causes the motor to move the drive member in an opposite direction.

6. The apparatus according to claim 1 wherein the re-engagement circuit provides a motor drive signal that causes the motor to move the drive member in a direction so that the first element re-engages the second element.

7. The apparatus according to claim 6 wherein the re-engagement detecting circuit comprises a movement detecting circuit that detects movement of the drive member, and wherein the re-engagement detecting circuit detects re-engagement of the first element with the second element when the movement detecting circuit does not detect movement of the drive member for a selected time interval.

8. The apparatus according to claim 6 wherein the re-engagement detecting circuit comprises a position detector that detects an engagement position of the first element relative to the second element.

9. The apparatus according to claim 8 wherein the position detector detects a position of the drive member relative to the driven member that corresponds to engagement of the first element with the second element.

10. The apparatus according to claim 1 further comprising a re-engage command circuit that provides the re-engage command signal.

11. The apparatus according to claim 10 wherein the re-engage command circuit comprises a manually operated switch.

12. An apparatus for controlling a derailleur, wherein the derailleur includes a motor that drives a drive member, a driven member driven by the drive member, and a clutch having a first element that disengages from a second element when substantial resistance exists in a power transmission path between the drive member and the driven member, wherein the apparatus for controlling the derailleur comprises:

a re-engage command circuit that provides a re-engage command signal, wherein the re-engage command circuit comprises:

a parameter sensor that senses an operational parameter associated with at least one of the drive member or the driven member;

a disengagement determining circuit operatively coupled to the parameter sensor to determine when the operational parameter does not correspond to an expected value; and

a re-engage command signal providing circuit operatively coupled to the disengagement determining circuit to provide the re-engage command signal when the disengagement determining circuit determines that the operational parameter does not correspond to the expected value;

a re-engage command receiving circuit that receives the re-engage command signal to re-engage the first element with the second element when the first element is disengaged from the second element; and

a re-engagement circuit that re-engages the first element with the second element in response to the re-engage command signal.

13. The apparatus according to claim 12 wherein the disengagement determining circuit determines when the operational parameter does not correspond to the expected value when the drive member is driven by the motor.

14. The apparatus according to claim 12 wherein the parameter sensor senses a position of the drive member relative to the driven member, and wherein the disengagement determining circuit determines when a position of the drive member relative to the driven member does not correspond to an expected position of the drive member relative to the driven member.

15. A bicycle derailleur apparatus comprising:

a base member adapted to be mounted to a bicycle frame;

a movable member that rotatably supports a chain guide;

a linkage mechanism coupled between the base member and the movable member;

a motor that drives a drive member;

a driven member driven by the drive member;

a clutch having a first element that disengages from a second element when substantial resistance exists in a power transmission path between the drive member and the driven member;

a re-engage command receiving circuit that receives a re-engage command signal to re-engage the first element with the second element when the first element is disengaged from the second element; and

a re-engagement circuit that re-engages the first element with the second element in response to the re-engage command signal;

wherein the re-engagement circuit comprises a re-engagement detecting circuit that detects when the first element re-engages with the second element.