Patent ID: 7464472

Claim:
A pipe cutting apparatus, comprising a body, a cutter head ( 1 ) bearing-mounted rotatably on the body, having a centre rotation axis (C) and having a cutting gap ( 2 ) which opens radially sideways for receiving a pipe to be cut, pipe securing elements ( 8 ) for fixing the pipe on said centre rotation axis (C) immovably relative to the body, support rolls ( 21 ) in the cutter head ( 1 ) for supporting the pipe during a cutting process, and a cutting blade ( 22 ) in the shape of a sharp-edged disk present in the cutter head ( 1 ), which, during rotation of the cutter head ( 1 ), is adapted to be advanced towards the centre rotation axis (C) for cutting the pipe, characterized in that the cutter head ( 1 ) is provided with a shifting and locking mechanism ( 12 - 20 , 28 - 40 ) for the support rolls ( 21 ), which, regardless of the diameter of a pipe to be cut, shifts and locks the support rolls ( 21 ) with a single drive and/or control against the surface of a pipe for cutting support, and wherein said shifting and locking mechanism further comprises: a slotted crank plate ( 12 ), rotatable about said rotation axis (C) relative to the cutter head ( 1 ) and including an arcuate guide slot ( 15 ) pivoting a swing arm ( 16 ) for the support roll ( 21 ), a crank plate shaft ( 30 ), having its gear ( 31 ) meshed with a toothed arc ( 28 ) of the slotted crank plate ( 12 ) for rotating the crank plate shaft ( 30 ) as the slotted crank plate ( 12 ) is turned for shifting the support rolls ( 21 ) against the surface of a pipe, a freewheel clutch ( 32 ) in association with the crank plate shaft ( 30 ) for allowing rotational motion of the crank plate shaft ( 30 ) in a direction, yet blocking the rotational motion in an opposite direction and thereby locking the slotted crank plate ( 12 ) in any position at which the support rolls ( 21 ) collide with the surface of a pipe to be cut.