Stripping compacted sand mould from tubular pattern - where pattern plate contains spring insert exerting pressure on sand (NL050477)

摘要

Pattern plate is fitted with >=1 patterns for mfg. sand moulds for casting, esp. tubular metal parts or bushes. The pattern plate is provided with a spring insert, at least in the region of the pattern, the insert acting as a store of energy and being compressed when the sand is compacted. The insert is pref. made of plastic or rubber with Shore-A hardness 25-50, esp. 45%; alternatively a spring steel plate, or a helical metal coil spring may be used. Used in casting pipe fittings made of steel or cast iron, where the compacted sand tends to remain in the hollow pattern so defective moulds are produced. The spring insert drives the sand out of the pattern when the compacting pressure is released.