PURPOSE: To omit a useless action in the case of a wrong extraction and to simplify a controller, by a method wherein the extraction is confirmed by the stroke length of an air cylinder rod.
CONSTITUTION: When a chuck unit 2 of an automatic extracting device 1 is positioned at a molding unit, air cylinder 4...4 mounted at a chuck plate 3 are actuated. When rods 5...5 are stretched by functioning of the cylinders, detecting rods 8...8 are simultaneously moved to the left shown in the drawing. Reactors 9...9 located at the detecting rods 8...8 are moved together with the movement of the detecting rods. Contact strips of limit switches 10...10 are brought into contact at a stroke position which is required for grasping of a molded product 6, and the switches turn on or off to send molded product extraction signals. On the contrary, in the case of the chuck not grasping the molded product 6, the detecting rods 8...8 move further forward, the reactors 9...9 being positioned outside an extraction confirming zone. Thus, where the reactors 9...9 are positioned outside the extraction confirming zone immediately after they come in contact with the switches 10...10, the extraction confirming signals are not issued.