| 摘要 |
PROBLEM TO BE SOLVED: To provide a rack and pinion drive mechanism for moving a substrate tray, which can prevent tooth tips of a rack and a pinion from bumping upon each other with a simple structure so as to allow the rack and the pinion to smoothly mesh with each other. SOLUTION: A rack and pinion drive mechanism comprises a rack 11 fixed to a substrate they 13, a pinion 12 rotatably coupled to a power transmission mechanism, for meshing the rack and pinion so as to feed the tray by the rotary motion of the pinion, a position adjusting plate 22 provided to a pinion shaft and having a circular part formed therein with a plurality of protrusive parts having a synchronized relation with the phase of the teeth of the pinion, a magnet 23 for stopping the position adjusting plate at a predetermined position, a clutch mechanism 31 for engaging and disengaging between the power transmission mechanism and the pinion shaft, and a rack detector 33 for setting the clutch mechanism in an engaging mode or a disengaging mode. |
