| 摘要 |
A phase change mechanism (10) is described for coupling a drive member (12) to a driven member (14). The mechanism comprises a cam plate (30) rotatable about the central axis of the mechanism and having cam surfaces (30a) that lie on opposite sides of the central axis and that are oppositely ramped in the axial direction. Cam wedges (54) are mounted for axial movement relative to the cam plate, each cam wedge having a cam surface (54a) engaging a respective one of the cam surfaces (30a) on the cam plate (30). Each wedge (54) is also pivotable at its end remote from the cam surface (54a) about an axis generally parallel to, and radially offset from, the central axis. A hydraulic jack is provided to cause relative axial movement between the cam wedges (54) and the cam plate (30), the engagement of the cam surfaces (54a) of the cam wedges (54) and the cam plate (30) causing the cam plate (30) to rotate about the central axis in response to the relative axis movement, the wedges (54) at the same time pivoting to maintain area contact between the cam surfaces on the wedges (54) and the cam plate (30). The cam wedges (54) or the cam surfaces (30a) on the cam plate (30) are allowed to rock to maintain surface contact. |
