| 摘要 |
<p>The method conditions the advancement of multiple perforations in a tube in order to establish alignments of holes (27) and (28) which follow interspaced generatrices on the tube (26) and are images of each other. Two perforation tools (23) are used, said tools being horizontally moved in a synchronous and opposing manner along an axis (P) transverse to the longitudinal axis of the tube (26). A carrying structure (13) that can move slidingly above the tube (26) provides the perforation tools (23) with translational movement means.</p> |
