Abstract: The molding machine comprises a station (1) with a chamber (2) that is closed between a front plate (5) that can move and swivel and a rear plate (8) associated to an extraction piston (9), forming a shell (3) in said chamber (2) by blowing sand through an upper hopper (4). The shell (3) obtained is pushed by the piston (9) until the rear of a row of shells (3?) placed on a conveyor (7) that places them opposite a casting station. The motion of the shell (3) pushed by the extraction piston (9) is independent of the motion of said piston after being incorporated in the row of shells, and is provided exclusively by the conveyor system (7), thereby providing a shorter working cycle while preventing deterioration of the shells as they are not compressed by the piston (9) when it pushes against the rear of the row of shells (3?).

Abstract: The molding machine comprises a station (1) with a chamber (2) that is closed between a front plate (5) that can move and swivel and a rear plate (8) associated to an extraction piston (9), forming a shell (3) in said chamber (2) by blowing sand through an upper hopper (4). The shell (3) obtained is pushed by the piston (9) until the rear of a row of shells (3′) placed on a conveyor (7) that places them opposite a casting station. The novelty of the invention lies in that the motion of the shell (3) pushed by the extraction piston (9) is independent of the motion of said piston after being incorporated in the row of shells, and is provided exclusively by the conveyor system (7), thereby providing a shorter working cycle while preventing deterioration of the shells as they are not compressed by the piston (9) when it pushes against the rear of the row of shells (3′).

Abstract: A tubular sand molding chamber having two conventional movable walls one mounted on a piston for compacting and expelling the cake and the other pivotably mounted on a displaceable hinge arm for opening the chamber, but having side walls that are also movable is disclosed. Each movable side wall includes a plate (11) mounted on a respective plate-holder (12) that is connected to guides (13) for sliding the side wall on a fixed support (14) through the action of a respective hydraulic cylinder (15), in such a manner that the effective width of the chamber be adapted to different cake sizes, in order to minimize the consumption of sand. However, the movable end wall that are mounted on a faceplate (20) affixed to a hydraulic cylinder and pivotably mounted on the hinge arm, respectively, for the compacting and expelling the sand cake, have replaceable plate assemblies.