| 摘要 |
A linear actuator for selectively moving an assembly relative to a support frame along a predefined linear path. The linear actuator includes a drive shaft having a cylindrical surface, means for rotatable mounting the drive shaft to the frame for rotation of the drive shaft about the axis of the cylindrical surface, and means coupled to the drive shaft for rotating same about such axis. A carriage forms part of the assembly with the remainder of the assembly being mounted to the carriage and including a roller. Means are included for mounting the roller to the carriage with the roller being rotatable about a first axis and pivotable about a second axis perpendicular to the first axis. Means are also included for mounting the carriage to the support frame with the carriage and thus the assembly being movable relative to the support frame along the predefined linear path and with the roller being in frictional engagement with the cylindrical surface of the drive shaft whereby the roller is caused to rotate about the first axis by rotation of the drive shaft when the first axis is parallel to the axis of the drive shaft and is additionally caused to move along the predefined linear path during rotation of the drive shaft when the first axis is oblique to the axis of the drive shaft. The center of mass of the assembly lies along a line parallel to the axis of the drive shaft and substantially intersecting or at least closely adjacent the nip between the roller and the cylindrical surface of the drive shaft. Means are further included for controllably pivoting the roller about its second axis to control movement of the roller and thus the carriage and assembly along the predefined linear path during rotation of the drive shaft. |
