Abstract: This circular rolling mill has a fixed main frame, a pair of cylindrical rollers, internal and external, to shape internal and external radial faces of an annular part and supported by a first secondary frame mounted on the main frame, as well as a pair of conical rollers, upper and lower, to shape opposite front faces of the part and supported by a second secondary frame mounted on the main frame. At least one rack and pinion assembly moves a roller in translation relative to one of the secondary frames. At least one electric geared motor drives the pinion of the rack and pinion assembly. The electric geared motor is fixedly mounted relative to one of the auxiliary frames. A fluid discharge mechanism is interposed in a kinematic chain for transmitting force between the rack and the roller moved by this rack. The fluid discharge mechanism has at least one variable volume chamber supplied with pressurized fluid and the volume of which varies as a function of the relative position of the roller and of the rack.

Abstract: The invention relates to a bush widening apparatus and a process by means of which it is possible to partially, in sections, forge at relatively low investment costs large and heavy bush blanks by means of a motor-driven, e. g. hydraulic, forming tool, and during which process both the diameter and the height of these banks increase in size.