| 摘要 |
1,166,182. Moulding plastics materials. DUNLOP CO. Ltd. 25 Jan., 1967 [15 Feb., 1966], No. 3642/67. Heading B5A. An elastomeric article is produced in a mould having at least one elongated projection for moulding a depression in the article, the projection having at least one vent passage extending therethrough adjacent its base, a part of the passage having a transverse cross-sectional area smaller than the transverse cross-sectional area of the remainder thereof. A pneumatic tyre mould 11, 12 has projections 15 for moulding tyre grooves, and the vent passage 16 of each projection is circular in transverse cross-section and tapers from one end to the other. Alternatively each passage is cylindrical with a convergent end, or it may diverge towards its ends from a mid-point thereof. |
