Patent ID: 6253827
Filing Date: 2001-07-03
Classification: B22C

Abstract:
A method of compacting molding sand in producing a sand mold by using a pattern plate provided with a pattern thereon and a plurality of vent holes therein around the pattern, comprising the steps of:placing a flask on the pattern plate at a location outside the vent holes;introducing molding sand into the flask;disposing a plurality of compressed gas guiding pipes each having a lower end opening above a top surface of the molding sand introduced into the flask such that lower end openings of the gas guiding pipes face the top surface of the molding sand in the flask, each of the gas guiding pipes being capable of discharging from its lower end opening a gas flow having a pressure that is controllable independently from the pressure of the gas flow discharged from each other one of the gas guiding pipes; anddischarging gas flows from the lower end openings of the gas guiding pipes such that each of the gas flows has an independently controlled pressure, to cause the gas flows to pass through the molding sand in the flask and through the vent holes, thereby compacting said molding sand in the flask with a degree of compaction that is independently controlled at each of at least two horizontally spaced locations of said molding sand, wherein each of the horizontally spaced locations of the molding sand is below a different one of the gas guiding pipes.