Patent ID: 7241086

Claim:
An apparatus for machining a pipe end, the apparatus comprising: a tool head rotatable about a pipe end and having an axis of rotation; a plurality of tool holders angularly equispaced about the axis and radially shiftable on the tool head; a respective machining tool engageable with the pipe end and clamped on each of the tool holders; a plurality of actuators extending parallel to the axis and displaceable relative to the tool head for shifting the tool holders radially on the tool head, the actuators having extremities proximal to the pipe end and extremities remote from the pipe end, the extremities proximal to the pipe end having teeth; a frame common to and connected with the actuators at the extremities remote from the pipe end; a plurality of first racks each on a respective one of the tool holders and meshing with the teeth of the respective actuators for radial displacement of the tool holders upon displacement of the actuators parallel to the axis relative to the tool head; respective second racks extending radially and fixed on the tool holders; pinion gears rotatable about pinion rotation axes parallel to the axis of rotation of the head and meshing directly with the second racks on the tool holders; and balancing weights formed directly on the pinion gears and having centers of mass offset from the respective pinion rotation axes, the balancing weight of each pinion gear lying between a diameter of the respective pinion gear and an outer periphery of the respective pinion gear.