PURPOSE: To make it possible to relieve chips bit by clamping rolls irrespective of the size of the space between the clamping rolls, by constituting a hydraulic cylinder for pipe clamping arms with a large diameter chamber and a small diameter chamber, and as well by fitting a floating piston in the large diameter chamber.
CONSTITUTION: A cylinder 14 for actuating arms 8 for clamping a pipe P, is constituted with a large diameter chamber 13 and a small diameter 14. A floating piston 15 is fitted into the large diameter chamber 13 and a piston 10 is fitted in the small diameter chamber. The pipe P is clamped between a pair of devices which are opposed to each other under the condition in which hydraulic pressure is applied such that the floating piston and the piston leave away from each other in the case of the pipe having a small diameter, but they approach together in the case of the pipe having a large diameter. In both cases, when chips are bit by clamping rollers 4, the arms 8 are temporarily set free, due to the provision of relief valves 18, and then clamp the pipe again.
KONDOU SUSUMU
YANO MASATOKI
