| 摘要 |
PURPOSE:To assure a normal operation, to stabilize a pouring stage and to improve productivity by having a mechanism to freely open and close, as desired, a valve disk which is freely movable upward and downward with regard to a spool and providing a detector for valve closure. CONSTITUTION:A spool 8 is preliminarily raised up to an initial attitude position and is detached from an insertion holes 9 of cradles 10, 10' in the pouring stage to a cavity 7. The spool 8 descends to fit the bottom end thereof into the holes 9 at the point of the time when the pouring stage is started. At the same time, the valve disk 17 is pressed to a valve disk receiving part 41 of the cradles 10, 10' to set a device 1 for venting gas in a metallic mold to the mold 2. The 1st three-way valve 37 is then operated to supply 36, 33 the working air under a set pressure from a compressed air source 39 to the 1st cylinder chamber 23 to energize a piston 22 upward. As a result, a recess of a valve stem 18 retreats a steel ball 28 to unlock the valve disk 17, then the valve disk ascends and the top edge of the disk 17 contacts with a valve seat 31 at the bottom end of the spool 8 via the valve stem 18 thereby fully closing a gas vent passage 20 and interrupting the communication with the cavity 7 through a bypass passage 32. |
