Teaching storage means stores teaching data created on the basis of signals from a first pulse generator, a first shaft detector, a second pulse generator, and a second shaft detector, in a storage unit as a sequence control program of molding operation of a self-hardening mold when teaching operation of throwing kneaded self-hardening foundry sand from a discharge port into a molding flask is performed by manually moving a conveyor arm and a kneading arm. Molding playback means reads out the sequence control program from the storage unit to control and drive a first pivot motor and a second pivot motor on the basis of the sequence control program to pivot the conveyor arm and the kneading arm, and then throws the self-hardening foundry sand from the discharge port of the kneading arm into the molding flask to reproduce the molding operation.

Teaching storage means stores teaching data created on the basis of signals from a first pulse generator, a first shaft detector, a second pulse generator, and a second shaft detector, in a storage unit as a sequence control program of molding operation of a self-hardening mold when teaching operation of throwing kneaded self-hardening foundry sand from a discharge port into a molding flask is performed by manually moving a conveyor arm and a kneading arm. Molding playback means reads out the sequence control program from the storage unit to control and drive a first pivot motor and a second pivot motor on the basis of the sequence control program to pivot the conveyor arm and the kneading arm, and then throws the self-hardening foundry sand from the discharge port of the kneading arm into the molding flask to reproduce the molding operation.

A valve device (10) having a check valve mechanism (20) having a valve rod (21) and a closing element (22) disposed on one end of the valve rod (21) and intended for the compressed-air supply to a consumer (11), the valve device (10) further having an actuation mechanism (30) having a hydraulic cylinder (31), the piston (32) of the hydraulic cylinder (31) being firmly connected to the valve rod (21) and being hydraulically driven within the cylinder casing (33) of the hydraulic cylinder (31) in order to actuate the check valve mechanism (20). A control mechanism (40) for controlling the piston movement and a measuring mechanism (50) for detecting the piston position is comprised, a proportional-valve mechanism (60), which is controllable by the control mechanism (40) as a function of the piston position, being connected to the hydraulic cylinder (31) in a fluid-conducting manner. A molding machine and method for controlling a valve device are also disclosed.