PLUG FOR MANUFACTURING SEAMLESS PIPE, DEVICE FOR ATTACHING/DETACHING ITS PLUG BAR AND ITS AUTOMATIC EXCHANGING DEVICE

摘要

PURPOSE: To carry out a plug changing operation easily and in a short time, with respect to a plug for manufacturing a seamless pipe, by providing a hollow part with a female screw in the opening side and making the inner part a cavity with its bore larger than the valley of the female screw and its length longer than that of the female screw. ;CONSTITUTION: The appearance of a plug is a cannonball shape, and the inside is hollow 6. The opening of the hollow part 6 is connected with a plug bar, and a female screw 4 is provided to be used at the time of separation. The inner part of the hollow part is a cavity whose bore is larger than the valley of the female screw 4 and whose length is longer than that of the female screw. The number of screw threads of the female screw 4 is somewhat smaller than the ordinary engaging example of a screw, and the pitch is on the large side so as to prevent the screw from falling while in use. Consequently, the plug is easily attached/detached from the device for attaching/detaching the plug.;COPYRIGHT: (C)1995,JPO