Actuator for a bicycle gear-shift

• US 20040014541A1
• Filed: 04/25/2003
• Published: 01/22/2004
• Est. Priority Date: 04/26/2002
• Status: Active Grant

• Current Assignee: Campagnolo S.R.L.
• Original Assignee: Campagnolo S.R.L.
• Inventors: Dal Pra, Guiseppe
• Granted Patent: US 7,086,974 B2
• Time in Patent Office: Days
• US Class Current: 474/70
• CPC Class Codes: B62M 25/08 with electrical or fluid transmitting systems
• CPC Class Codes: B62M 9/122 electrically or fluid actuated; Controls thereof
• CPC Class Codes: B62M 9/1244 limiting or positioning the movement

Abstract

A bicycle gear-shift actuator (10, 100) having an articulated quadrilateral support (11) with four connecting rods (21, 22, 23, 24) hinged together by four pin elements (41, 42, 43, 44), and a motor member (12), having a variable length output shaft that travels along a drive axis (13) between two opposite pin elements (41, 42) to move them for deforming the articulated quadrilateral (11). Preferably, the drive axis (13) perfectly intersects the pin axis (32) of at least one (42) of the two pin elements (41, 42).

Claims

1. Actuator device (10, 100) for a bicycle gear-shift, comprising

an articulated quadrilateral (11) with four connecting rods (21, 22, 23, 24) hinged together according to four pin axes (31, 32, 33, 34) by four pin elements (41, 42, 43, 44), in which the first connecting rod (21) is intended to be integrally fixed to the bicycle frame, the second connecting rod (22) is opposite to the first connecting rod (21) in the articulated quadrilateral (11) and is intended to be fixed to a support for a gear-shift derailleur;

a motor member (12), having a variable length according to a drive axis (13) and active between two opposite pin elements (41, 42) to move them towards and away from each other deforming the articulated quadrilateral (11);

characterised in that

the drive axis (13) substantially intersects the pin axis (31, 32) of both the two pin elements (41, 42) between which the drive member (12) is active.

2. Device according to claim 1, in which the drive axis (13) perfectly intersects at least one of the pin axes (31, 32) of the two pin elements (41, 42) between which the motor member (12) is active.

3. Device according to claim 2, in which the motor member (12) comprises an electric motor (52) housed on a support (51) mounted on a first (41) of the pin elements, a screw (53) arranged axially along the drive axis (13) and put into rotation by the electric motor (52), a nut screw (54) engaged with the screw (53) and fixed to a second (42) of the pin elements opposite the first (41), wherein the drive axis (13) perfectly intersects the axis (32) of the second pin element (42).

4. Device according to claim 3, in which the connecting rods (21, 22, 23, 24) have a substantial width in the direction of the pin axes (31, 32, 33, 34), with such a width defining an internal space in the articulated quadrilateral (11), wherein the motor member (12) is arranged inside such an internal space.

5. Device according to claim 4, in which the nut screw (54) comprises a tubular body (541) threaded internally, and two pin portions (542, 543) opposite each other and perpendicular to the tubular body (541).

6. Device according to claim 5, in which the second pin element (42) also comprises two opposite pins (421, 422), each inserted in hinging holes formed in the connecting rods (22, 23) converging in the second pin element (42) and in the pin portions (542, 543) of the nut screw (54).

7. Device according to claim 3, in which the connecting rods (21, 22, 23, 24) have a substantial extension in the direction of the pin axes (31, 32, 33, 34), with such an extension defining an internal space of the articulated quadrilateral (11), wherein the motor member (12) is arranged outside of such an internal space.

8. Device according to claim 3, in which a degree of freedom is provided between the motor (52) and the articulated quadrilateral (11).

9. Device according to claim 8, in which the degree of freedom is provided by a clearance which allows the nut screw (54) small movements in the direction of the axis (32) of the second pin element (42).

10. Device according to claim 8, in which the degree of freedom is provided by a Hooke'"'"'s joint between the screw (53) and the motor (52).

11. Device according to claim 5, in which the tubular body (541) of the nut screw (54) is closed at one of its ends (544) and has a length such as to receive the screw (53) during the maximum contraction of the motor member (12).

12. Device according to claim 1 further comprising a mechanical fuse in the coupling between the motor element (12) and the articulated quadrilateral (11).

13. Device according to claim 12 in which the mechanical fuse comprises a coupling with calibrated interference between the electric motor (52) and its support (51), such as to allow relative axial movements only when a predetermined retaining stress is exceeded.

14. Device according to claim 12, in which the mechanical fuse comprises a coupling with calibrated interference between a threaded bush (545) engaged with the screw (53) of the motor (52) and a receiving seat thereof (546) in the tubular element (541) of the nut screw (54), such as to allow relative axial movements only when a predetermined holding stress is exceeded.

15. Device according to claim 12, in which the mechanical fuse comprises a coupling with calibrated interference between the Hooke'"'"'s joint and at least one among the motor (52) and the threaded screw (53).

16. Device according to claim 1 in which the drive axis (13) perfectly intersects the pin axis (31, 32) of both of the two pin elements (41, 42) between which the motor member (12) is active.

17. Device according to claim 1 in which the articulated quadrilateral (11) is an articulated parallelogram.

18. A bicycle gear-shift actuator (10, 100) comprising:

an articulated quadrilateral support (11) with four connecting rods (21, 22, 23, 24) hinged together by four pin (41, 42, 43, 44) which define;

a motor member (12), having a variable length output shaft that traverses along a drive axis (13) extending between two diagonally opposed pins (41, 42) and moves them toward and away from each other to deform the articulated quadrilateral support (11); and

the drive axis (13) substantially intersects each pin axis (31, 32) of the diagonal pins (41, 42).

19. The actuator of claim 18 wherein the drive axis (13) perfectly intersects at least one of the pin axes (31, 32) of the two pin elements (41, 42) between which the motor member (12) is active.

20. The actuator of claim 18 wherein the motor member (12) is arranged inside an internal space defined by the articulated quadrilateral (11).