| 摘要 |
A rotary indexing table comprises a stationary gear mounted on a base, a rotary drive mounted within the base and carrying a first crank arm, and a planetary gear on the first crank arm engaging the stationary gear. A second crank arm is mounted on the planetary gear, and has a freely rotatable drive stub which engages and drives a radially directed force receiving member mounted on a rotatable table. The rotation axis of the freely rotatable drive stub overlies the circumference of the planetary gear; and as the planetary gear rotates, the drive stub is coupled to the force receiving member so as to freely move along it in a reciprocating manner. When the longitudinal axis of the first and second crank arms are aligned, the indexing table is locked in place and cannot be moved by an external force. One of the stationary gear and the planetary gear comprises a gear assembly having two identical gears, one of which is slightly rotationally offset with respect to the other, so that there is no backlash between the gears no matter which direction the planetary gear is rotating as it moves around the periphery of the stationary gear.
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