| 摘要 |
PURPOSE:To permit easy washing of an inside cylinder in pushing forcibly the sand packed in the inside cylinder to a mold member with compressed air by embedding plural air vents in the outside circumferential surface of the inside cylinder thereby improving the inflow and discharge of compressed air and preventing the back flow of the sand. CONSTITUTION:Compressed air is admitted through air vents 28 of an inside cylinder 12 into the cylinder 12 to push forcibly the sand 21 packed in the cylinder 12 to the hollow part 15C of a mold member 15. When the supply of the compressed air is stopped, a part of the compressed air flows backward and discharged through the air vents 28 of the cylinder 12 into an air chamber 11C but the sand 21 is not discharged. The reason lies in that the meshes of the net of each vent 28 are smaller than he particles of the sand 21 thus preventing the back flow of the sand 21 while allowing satisfactory passage of the air. |
