| 摘要 |
<p>2138947 9400278 PCTABS00030 An apparatus for shaping perforations of sheet material (16) which comprises a first mould structure (18, 44) at one side of the sheet material and a complementary mould structure (30, 52) at the other side of the sheet material to cooperate with the first mould structure wherein the structures are arranged to be reciprocated and are capable of meeting approximately half way through the sheet material whereby to shape the perforations between them. The apparatus can include a needle (10) so that perforations are simultaneously formed and shaped, or it may be used to shape pre-formed perforations. If a needle is included it may be of the ultrasonic type or it may be heated, e.g. electrically heated (40). If a needle is used, one of the mould structures may be defined by an appropriate formation (32) on the needle, or the structure may be separate.</p> |
