| 摘要 |
<p>PURPOSE:To mold a gas hardened casting mold at a high hardening speed by the use of a simple pattern box by providing a hollow mandrel in a cavity part, and performing packing of molding sand and gushing of a hardening gas while sucking the gas from the inside. CONSTITUTION:A hollow mandrel 12b having many vent holes 12d is provided in the cavity part 4 of a segmental pattern box 1 of a wooden pattern or the like consisting of a left mold 2 and a right mold 3 of a pattern body, and many vent holes 6 communicating with a hollow chamber 5 are punched on the surface of the part 4. The cavity part is connected to an evacuating device 11 through suction holes 7, a conduit 8, a main pipe 9, an on-off valve 10, etc. While negative pressure is developed in the part 4 by the operation of the device 11, gas hardenable molding sand 13 is packed into the part 4 through a sand blowing port 12c, a sand supply port 4a, etc. from a hopper (not shown); thereafter, the hardening gas is supplied from a gas generator 20 into the hollow part 12b' of the mandrel 12b and is passed through the sand 13, whereby the gas hardened casting mold is obtained.</p> |
