Foundry sand core or mould making machine - using evacuated core-box to achieve uniform compaction of sand, esp. when mfg. large, complex cores

摘要

A core box provided with air exit holes, and used to make either a mould or a core, is located in a vacuum chamber. Chamber has a roof with a sliding shutter provided with two holes, one of which is located below a sand hopper fixed on shutter and used to shoot sand into the evacuated core box via a single hole in the latter. During the entire shooting operation, the sand flows at a constant speed into the corebox; but the speed can pref. fluctuate by (+-) 25% from a mean value. Air is pref. used to fluidise the sand which pref. falls freely into the evacuated corebox. The second hole in shutter is pref. used to feed reaction or catalyst gases, compressed air or scrubbing air into the corebox. Used esp. to make long cores of complex shape with uniform properties.