| 摘要 |
PURPOSE:To pack uniformly molding sand by controlling automatically individual segments and a lower pressurizing head by program. CONSTITUTION:Molding sand 13 is charged into a molding flask 06 and an upper pressurizing head 02 is lowered by an upper pressurizing cylinder 01 until the top ends of upper pressurizing segments 03 contact with the sand 13. The segments 03 in the parts where the thickness of the molding sand is large are lowered by a hydraulic mechanism to pressurize the sand 13 according to a predetermined program. Solenoid valves of the hydraulic system are then successively opened with time lags in order of the increase in the sand thickness to lower successively the segments 03 thereby pressurizing the sand 13. The pressure in the hydraulic system of the specific upper segment is detected with a pressure detector and when the prescribed pressure is attained, a lower pressurizing cylinder 11 operates and a lower pressurizing head 10 ascends to pressurize the sand 13. When the pressures in the cylinders of the segments 03 and the head 10 attain the prescribed pressure, the pressure control valves of the hydraulic systems for the upper and lower pressurizing segment cylinders close the routes thereof. |
