| 摘要 |
PURPOSE:To improve sealing performance and smooth opening motion in a vacuum breaker of a vacuum sucking type transportation device by firstly reciprocating a child valve by driving a motor, in the next step, actuating a parent valve and arranging a damping means which absorbs the excessive approach motion of the child valve in closing. CONSTITUTION:When a rod 5 is reciprocated in the vertical direction by the drive of a motor 1, firstly a child valve 9 opens and closes an air hole 4. In the next step, when the rod 5 is further reciprocated, a parent valve 3 moves in the vertical direction also to completely opens and closes the air hole 4. When the child valve 9 closes along with the lowering of this rod 5, since this closing motion is somewhat excessively performed, and upper limit switch 7 is provided to stop the rod 5 for improving sealing performance. The over- lowering quantity is absorbed by the damping mechanism 8 which is provided at the head of the rod 5 and has elasticity in the axial direction. |
