Abstract: A first quantity of all the molding sand necessary to produce a mold is fed in the mold space, the first quantity being one of at least two parts divided from the total molding sand. The mold space is evacuated and then air is introduced into the mold space at the air-pressure rising rate of 30--to 500 kg/cm.sup.2 /sec. Another quantity of the molding sand is fed into the mold space, the mold space is evacuated and then air is introduced into the mold space at the air-pressure rising rate of 30--to 500 kg/cm.sup.2 /sec. The apparatus includes a sand passage through which each quantity of sand is fed into the mold space, and a gate for closing the sand passage thereby closing the mold space to allow the mold space to be evacuated and then subjected to a pressure increase.

Abstract: A method and apparatus is provided for increasing the packing density and strength of sand for gas-hardening casting molds. The method is characterized by the steps of filling spaces defined by a pattern plate 1 and a mold frame with gas-hardening casting sand 4, depressurizing a closed container 3 after the filled assembly has been conveyed thereinto, introducing air into the container 3, applying a pressure to the upper surface of the casting sand to increase its packing density, and hardening the casting sand by a hardening gas.

Abstract: An apparatus to produce a shell-like mold by vacuum sucking molding sand into a shell-like cavity defined by a cope and a drag is disclosed. The apparatus includes a drag and a cope mounted on the drag so that they define a shell-like cavity between them. The drag holds on its upper surface a pattern. The drag has a plurality of sucking apertures at places adjacent to the perimeter of the pattern. The sucking apertures communicate with a vacuum source. The cope has a single molding-sand-supplying bore which communicates with the cavity. To produce a shell-like mold, the molding sand is introduced from the bore into the cavity by means of a vacuum source.

Abstract: A method of filling a core cavity, wherein the entire core cavity is uniformly filled with highly compacted sand for molding the core without the need of providing many ventholes. The method is characterized in that sand for molding the core is drawn into the core cavity through an inlet to preparatorily fill the cavity, and then the thus prepared sand is repeatedly and sequentially compacted by impulsively pressurizing the sand, starting with the sand farthest from the inlet and ending with the sand nearest to the inlet.

Abstract: A method for connecting a plurality of cores in an assembly through adjacent surfaces of the adjacent cores is disclosed. This method includes the steps of: (a) forming a plurality of cavities between adjacent surfaces of two adjacent cores, the plurality of cavities being horizontally aligned and spaced apart along the adjacent surfaces; (b) arranging the plurality of cores in a row; (c) filling a hopper nozzle with a predetermined amount of connecting sand; (d) indexing the hopper nozzle above one of the cavities; (e) supplying compressed air into the hopper nozzle that contains the connecting sand, thereby projecting and charging the mass of the connecting sand from the hopper nozzle into the cavity; and (f) repeating steps (c), (d), and (e).

Abstract: Cores have a plurality of cavities defined by adjacent vertical side surfaces of two adjacent cores. These cavities are arranged horizontally and spaced apart along the surfaces. Providing such a plurality of cavities in the surfaces produces an increased total surface area extending in the direction where the cores mate or separate.

Abstract: The molding apparatus includes a table movable between an area where molding sand is fed and a mold-producing area for carrying a pattern plate on which a flask is mounted, a cylinder for vertically moving the table, a closing cover having an opening at the lower part thereof, the opening communicating with an upper opening of the flask. The closing cover has a stepped part such that the cross-sectional area of the lower part of the closing cover is smaller than that of the upper part thereof. At least one air-supply pipe communicates with the upper part of the closing cover and an air valve communicates with the air-supply pipe to introduce ambient air into the air-supply pipe. An opening is formed in an upper and side part of the closing cover for communicating with a vacuum source. A press plate is suspended in the closing cover for a vertical movement such that the press plate can be airtightly inserted into the small lower part of the closing cover.

Abstract: Molding sand (5) is fed into a space defined by a pattern plate (2) and a flask (3) mounted on the pattern plate (2), and the space is enclosed at the upper part of the flask (3) by a cover (6). The air in the enclosed space is evacuated to reduce the air pressure between the grains of the molding sand in the enclosed space to 1 Torr to 150 Torr, and then air is introduced into the enclosed space from the upper part of the space so that the pressure in the space can increase at the rate of 15 atm/s to compress the molding sand (5). The method eliminates the need for vent holes and enables the mold to be crack-free since the air flow is not reflected.

Abstract: A method of producing a mold core from green sand, wherein green sand is blown into a mold cavity which is sized to be greater than the size of the mold core to be obtained, so that a preformed mold body is prepared. The preformed mold body is then compacted by a compacting die having a cavity recess which is sized in conformity with the size of the mold core to be obtained, until the preformed mold body size is reduced to the final stage. In consequence, the green sand is compacted to develop uniform distributions of strength and hardness over the entire portion of the mold core as the product.

Abstract: An apparatus and method for making cores from green sand continuously and automatically. The method comprises blowing the green sand together with compressed air into a die cavity formed by a pair of dies, stabbing the green sand filled in the die cavity by stabbing rods to compact the green sand thereby to form a core, and applying a surface stabilizing agent to the surface of the core taken out from the dies, followed by drying of the core. Disclosed also is an apparatus suitable for carrying out this method.

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 core making machine for making a hollow core from green sand, capable of automatically performing a series of core making operation which has the steps of blowing the green sand into a horizontally split type die means from an opening formed in one side of the die means together with air to fill the die cavity, forcibly stabbing the green sand in the die cavity by a stabbing rod to compact and harden the green sand and extracting the rod thereby to form a hollow core, and taking out the thus made core from the die means after it has been splited.

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.

Abstract: A molding machine has a base, a pattern provided with a plurality of vent bores formed therethrough and mounted on the base, a molding flask arranged to be combined with the pattern, an upset frame superposed to the molding flask, cover means for making an airtight contact at its lower end with the upper surface of the base, molding flask or of the upset frame. Further, compressed air supplying means are provided for supplying compressed air into the closed space defined by the pattern, the molding flask and the upset frame, the space being filled with molding sand. The cover means include a cylindrical member and cover member. The cylindrical member slidably fits to the outside of the cover member in a telescopic manner, and is provided at its lower end with an inwardly projected flange.

Abstract: A molding apparatus having a pattern plate provided with vent through bores, a mold flask adapted to be placed on the pattern plate, an up-set frame adapted to be carried by the mold flask, a cover plate covering the upper end opening of the up-set frame, a squeeze plate disposed in the cover and movable into the up-set frame, and compressed air supplying means adapted to introduce compressed air into the space in the mold flask. After filling the space in the mold flask with the molding sand, the compressed air is introduced into the space in the mold flask by means of the compressed air supplying means. The air flows through the molding sand toward the vent through bores formed in the pattern plate so that the molding sand particles are packed and consolidated in the area around the vent through bores.