Abstract: A hopper for providing moulding sand having an opened top and a bottom member having through holes for discharging the sand is positioned spaced apart at a suitable distance horizontally from a cover member connected to a suitable source for generating gas for hardening the moulding sand. A pattern plate provided with vacuum evacuating means is disposed to be selectively connected to either one of the hopper and the cover member for discharging and filling the moulding sands into a flask placed on a pattern plate and for introducing hardening gas and allowing said gas to penetrate and permeate through the layer of sand filled in the flask to harden the filled sand, respectively. By using vacuum evacuation of a hollow chamber in the pattern plate instead of pressurized air and hardening gas under pressure, the entire moulding apparatus can be rendered lighter in construction and smaller in size, while any leakage of poisonous hardening gas can be completely prevented from occurring.

Abstract: A molding box apparatus having a horizontal tubular body and a pair of pattern plates having pattern surfaces complementary to the mold chambers to be formed fitting in the tubular body, at least one of the pattern plates being slidable in the tubular body. The apparatus further has a well pattern provided on the pattern surface of one of the pattern plates and a runner pattern provided on the well pattern and extending from one end of the latter substantially perpendicularly to the pattern surface. The end of the runner pattern is adapted to be slidingly received by a guide hole formed in the other pattern plate. With this apparatus, it is possible to easily produce a mold part of a vertical split type flaskless mold assembly.

Abstract: Disclosed is a gas hardening type molding machine wherein a vertical type molding box is disposed under a molding sand hopper having an upper part opened and a bottom part provided with a sand discharge port, and a mold cavity in the vertical split type molding box is communicated with both a vacuum device and a hardening gas generator through stop valves, thereby to conduct both the filling of molding sand and the permeation of a hardening gas by utilizing the suction operation of the vacuum device.

Abstract: A method of making a mold having the steps of supplying a molding sand containing a gas-hardenable binder into a space defined by a patter plate and a molding flask, covering the upper surface of the molding sand in a gas-tight manner with a film sheet, bringing the space in the molding flask into communication with a vacuum source to reduce the pressure in the space thereby to squeeze the molding sand by means of the film sheet, closing, after removing the film sheet, the upper opening of the molding flask, and connecting a hardening gas source to the space in the molding flask while reducing the pressure in the space to induce a hardening gas into the molding flask to make the gas penetrate the molding sand, thereby to harden the molding sand.