| 摘要 |
PROBLEM TO BE SOLVED: To enable a rotation preventive mechanism preventing relative rotations of two member to show strong rotation preventive force.SOLUTION: A rotation preventive mechanism 20 preventing relative rotations of a fixed plate 11 and a moving arm 14, has a coupling structure composed of a base 22 attached to the fixed plate 11, a drum 21 attached to the moving arm 14, a plate 23 coupling the base 22 and the drum 21 so as to relatively axial-rotate, spacer 24, and a shaft pin 29; and two twist springs 25A and 25B fixed on the base 22 at one side ends, and stopping rotations of the drum 21 by friction force with which outer peripheral surfaces are pressed on an inner peripheral surface of the drum 21. The two twist springs 25A and 25B are wound in the opposite directions to each other, restored in a diameter expanding direction from one side ends fixed to the base 22 in free states, and pressed on the inner peripheral surface of the drum 21.SELECTED DRAWING: Figure 6 |
