| 摘要 |
The device comprises a roller for longitudinally rolling a hollow blank (12). The roller comprises four rolling stands (1, 2, 3, 4), the first stand comprising two round-grooved cylinders (7, 8), the other three stands comprising four driven cylinders. A tapered mandrel (5) is held by a mandrel holder (11) and is maintained in the centre line of the stands by a centering and guiding apparatus (9, 9'; 10, 10'), so that a free concentric space is left between the mandrel and the cylinders through which the hollow blank, fed by a pusher, is to move. |
