| 摘要 |
PROBLEM TO BE SOLVED: To enable a surplus urethane foam layer to be generated from a vent hole by measuring a change in the gas pressure of a foaming step and activating an outer device simultaneously with the lowering of the internal gas pressure of a cavity to a zero level. SOLUTION: After infecting a raw material for an urethane foam into a die, both top and bottom forces of the die are closed, and a gas generated in the die is discharged to an atmosphere from a speed controller 10, passing through a pressure activating valve 4. In this case, a low pressure activating valve 5 is switched from 'open' to 'closed' by an exhaust pressure. If the foaming process is advanced, the exhaust pressure exceeds the set pressure level of a pressure switch 6, and an 'ON' signal is connected to a solenoid valve 7. Consequently the solenoid valve 7 is opened and a pilot valve 9 is opened to permit passage of an air to the low pressure activating valve 5. A resin is packed into a molding die, and the vent hole 2 of the top force is blocked, and at the same time, the exhaust pressure is reduced to a zero level. Further, the low pressure activating valve 5 is opened and the pressure activating valve 4 is closed. Thus the pressure switch 6 is turned OFF, to close the solenoid valve 7, and the resin is hermitically sealed in the die. Finally, the molding is taken out of the die by opening it. |
