| 摘要 |
An expandable coiler mandrel has a core (1), radially movable segments (2) around the core and hydraulic pistons (6) to move the segments (2) outwardly. To provide a mandrel in which all movements are actuated hydraulically, and in which tilting of the segments during expansion is avoided, the segments (2) are secured to the pistons (6) which are annular and mounted around pins (4) having heads to limit the movement of the segments. The pistons (6) can be urged in either direction by hydraulic fluid, to expand and retract the mandrel. Fluid for expansion is supplied by pressure cylinders. The pistons (6) associated with a single segment (2) are actuated by at least two of the pressure cylinders. |
