accordance with the type of a new work grip member 400a to be loaded the detection mechanism 610 consists of proximity switches 612 in the number identical to the number of the identification marks 650 and the proximiity switches 612 are arranged so as to detect the type of the new work grip member 400a in a combination of the on off switching of the proximity switches 612 as shown in fig4 a type of the new work grip member 400a loaded on the arm member 508 is detected by the detection mechanism 610 when the molding apparatus 15 the arm member 508 and so on are connected to each other in the on line control manner by the central control from a central control unit 612 on the one hand every type of work grip members 400 to be received by the arm member 508 is input in advance in the central control unit 612 operaton data for the arm member 508 with respect to every type of the work grip member 400 are memorized in an operation data memory circuit 614 the detection results on the type of the new work grip member 400a to be received by the arm membr 508 and the detection mechanism 610 are compared by a comparison circuit 616 when it is found identical to each other as a result from the comparison by the comparison circuit 616 on the one hand the operation data for the operation of the.