| 摘要 |
PURPOSE:To minimize the wear of the contacting sections of a weight and actuator so that the durability of an over-rotation preventing device can be improved, by operating the over-rotation preventing device only when the rotating speed of a rotating body exceeds a prescribed value. CONSTITUTION:When a rotating body 1 rotates, centrifugal force acts on a weight 2 and force toward the center of a spherical body 9 acts on the contact point of the notched groove 8 of the weight 2 and the spherical body 9. A component of the force acts to compress a spring 11, but pushing force is given to the spring 11 by means of an adjusting screw 10 so that the spring 11 does not contract at normal rotating speeds, and therefore, the weight 2 is held by the spherical body 9. When the rotating speed of the rotating body 1 exceeds a prescribed speed, the force acting on the spring 11 by the centrifugal force of the weight 2 becomes stonger than the pushing force of the spring 11 and the spring 11 is contracted. When the spring 11 is contracted, the spherical body 9 comes out of the notched groove 8 and the weight 2 instantaneously springs out and pushes an actuator 6, resulting in the emergency stop of the rotating body 1. |
