Machine for machining pipe ends, having a centering device for centering a tubular workpiece in relation to an axis of rotation

An apparatus for machining ends of a tubular workpiece, the apparatus comprising:

• at least one tool movable radially of a machining axis;
• clamp means for holding the tubular workpiece with an axis of the workpiece coaxial with the machining axis;
• means for rotating the workpiece about the machining axis while moving the tool only radially of the machining axis or for holding the workpiece stationary while orbiting the tool about the machining axis and moving the tool radially of the machining axis to machine an end of the workpiece;
• an arm pivotal about an arm axis parallel to and offset from the machining axis and having an open outer end;
• means for pivoting the arm about the arm axis between a centering position with the open outer end surrounding the machining axis and an out-of-use position with the outer end spaced from the machining axis;
• two pivot axles fixed on the arm, extending parallel to the machining and arm axes, and radially equispaced from the machining axis in the centering position;
• first, second, and third levers having respective outer ends, the first and second levers being pivoted on one of the pivot axles and the third lever being pivoted on the other pivot axle;
• a body coupled to all of the levers at pivot axes radially equispaced from the respective axles;
• and
• actuating means connected between the body and the pivot arm for, in the centering position, shifting the body between inner and outer positions on the pivot arm and thereby shifting the jaws synchronously radially of the machining axis between closely juxtaposed inner positions all radially equispaced from the machining axis and less closely juxtaposed outer positions also radially equispaced from the machining axis, whereby movement of the jaws between the respective outer positions into the respective inner position in the centering position of the arm can center a workpiece between the jaws on the machining axis.