| 摘要 |
<p>A projection or blade (6a) is provided on the head (6) of the ejection punch (5), which projection or blade (6a) occupies only a part of the thickness of the moulding impression and which is matched to the profile of the hole to be pierced, and a slight axial movement is imparted to the said punch, while the injected material is in the uncompressed state but still at the vulcanisation temperature, in order to cut the membrane of material which is located at the said blade. <IMAGE></p> |
