Power transfer device, orbital pipe cutting device and hydraulic chucking device

An orbital pipe cutting device for freely controlling advance and retreat of a cutting tool, comprising:

• a main body;
• a rotary body rotatable about an axis of rotation and coupled to one side of the main body and configured to make rotation;
• a power transfer device installed in the main body and the rotary body,
• wherein the power transfer device is configured to transfer external power to the rotary body and comprises:
• at least one double-action interlocking cylinder mounted to a rear surface of the rotary body and provided with a rod protruding toward the main body;
• a push unit installed in the main body and provided with at least one pusher protruding toward the rotary body;
• and
• a bearing disposed between the at least one pusher of the push unit and the rod of the interlocking cylinder and configured to allow for relative rotation of the pusher and the rod and for transfer of power between the pusher and the rod;
• and
• a double-action hydraulic cylinder installed on a front side of the rotary body and connected to the interlocking cylinder via a hydraulic closed circuit (HCC);
• a cutting tool mounted to a rod of the hydraulic cylinder and configured to reciprocate toward and away from a center of the rotary body along said axis of rotation;
• and
• a chuck installed on a front side of the main body and configured to fix a pipe such that an end portion of the pipe is placed within a machining range of the cutting tool.