An improvement in machine tools

摘要

A portable machine for facing the coupling flanges of large pipes comprises a base unit 10 adapted to be clamped to an end of a pipe, a power-driven member 30 rotateable on the base unit 10 about the axis of the pipe and having guides 32 tangential to that axis along which a carriage 70 is slideable by a power-driven leadscrew 48. A tool-holder 76 is slideable by a power-operated drive mechanism along guides on the tool-post 72 which is angularly-adjustable on the carriage 70 about an axis perpendicular to the guides 32. The powered drive of the tool-holder 76 along the guides on the tool-post 72 includes a shaft 50 journalled in the member 30 parallel to the leadscrew 48, the shaft 50 and the leadscrew 48 being driven alternatively. This alternative drive is taken from a sleeve surrounding a zone of the shaft 50, or in another embodiment from a reversible shaft driven in one direction at one speed and in the other direction at another speed.