| 摘要 |
PURPOSE:To keep the straightness of a movable portion high by disposing two driving force transmitting portions on the right and left of a guide mechanism, respectively. CONSTITUTION:When either a coarse adjustment handle 15 or a fine adjustment handle 13 of a coarse and fine adjustment co-axial handle 11 is rotated to drive a rack member 22 by a pinion 16a of a driving shaft 16, angular moments generated in right and left racks 22a, 22a opposite to each other to be cancelled so that the angular moment does not change with ascending and descending. Accordingly, the straightness of a lens barrel support table 4 can be kept high, so that there is no possibility of an error in measurement caused by moving the central axis of the lens barrel 10. As the straightness of the lens barrel support table 4 is kept high, the space between a scale 24 of an optical range finger 23 and an index can be kept correct so as to improve measurement accuracy. Furthermore, load of the lens barrel portion, which is conventionally applied to one rack, is divided by two racks 22a, 22a so as to decrease abrasion of the racks 22a. |
