| 摘要 |
PROBLEM TO BE SOLVED: To protect a movement of a part in the specified direction in fixing it with a screw. SOLUTION: A rectangular shaped projection 3c of a rear mirror tube 3 is equipped in both sides of a through hole 3b opposing to the vertical direction (X direction). When a screw 4 is inserted into this through hole 3b and a fixed hole (not shown in the figure) of an intermediate mirror tube passing through this and made to rotate, a take around force F1 caused by a rotation of the screw 4 works against the projection 3c by the initial contact of the lower part of a head 4a of the screw 4 with the projection 3c. The take around force F1 works strongly in the vertical direction to the opposite direction, that is Y direction, of the projection 3c and hardly works to the X direction because the projection 3c is formed opposite to the through hole 3b. By this reason, it becomes possible to fix both mirror cylinders with the screw 4 without changing a position of the rear mirror cylinder 3 in the X direction to the middle mirror cylinder 2.
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