Patent ID: 6619373
Filing Date: 2003-09-16
Classification: B22C

Abstract:
Apparatus for the gravity, lost-foam, casting of a metal casting comprising: (1) a bed of loose sand forming a mold having a molding cavity therein for shaping molten metal into said casting; (2) a flask containing said bed; (3) a fugitive pattern embedded in said sand and shaping said cavity, said pattern having the shape of said casting and comprising a polymeric foam pyrolizable by the molten metal; (4) a fugitive body attached to said pattern and forming a gating system in said sand for supplying molten metal to said cavity, said body having an underside and comprising said pyrolizable foam; (5) a downwardly-facing inlet to said gating system for admitting molten metal upwardly into said gating system into contact with said underside of said body; (6) a hollow sprue embedded in said sand for conducting molten metal to said inlet, said sprue being free of said foam and made from a material which is non-pyrolizable by molten metal; (7) a mouth at one end of said sprue higher than said pattern for admitting molten metal into said sprue; and (8) an upwardly-facing outlet at the other end of said sprue underlying said gating system and engaging said inlet for directing molten metal from said sprue upwardly into said gating system.