| 摘要 |
PROBLEM TO BE SOLVED: To provide a columnar body lift on which maintenance can be done at an early state when the columnar body lift mounted on a columnar body gets stuck.SOLUTION: A columnar body lift allows a nut 75 and a movable support part 31 to move by rotating a screw rod 74 with a motor 71, when a worm gear 37 cannot be actuated by a motor 38. The worm gear 37 connected to the movable support part 31 is disengaged from the motor 38 by moving in a disengagement direction. With the disengagement operation of the worm gear 37, a pair of right and left support arms engaged to the worm gear 37 is activated, and wheels mounted on the support arms are separated from the external peripheral surface of a tree trunk. |
