| 摘要 |
1,223,469. Injection moulding. SOC. APPLICAZIONI GOMMA ANTIVIBRANTI "SAGA" S.p.A. 22 July, 1968 [29 Sept., 1967], No. 34962/68. Heading B5A. [Also in Division F2] In a rubber-bush mounting element of the kind in which a rubber tube is secured between inner and outer more rigid tubes, the rubber is vulcanized and at least one of the "rigid" tubes (i.e. either the inner or the outer or both) is of a resilient plastics material such as nylon. The invention provides a method of making such an element whereby it is ensured that shrinkage strains set up in the rubber when it is vulcanised are taken up by resilient deformation of the plastics tube or tubes. In Fig. 1 the inner tube 10 is of metal and the outer tube 12 of plastics and they are shown fitted in a mould chamber 24 whose inner diameter exceeds the outer diameter of the tube 12. When unvulcanized rubber is forced into the mould through inlets 26 the outer tube is deformed. The extent of this deformation, determined by the difference in diameter between chamber 24 and tube 12, is such that it is at least equal to and preferably exceeds the anticipated shrinkage of the rubber upon vulcanization. The rubber is vulcanized in situ and the completed element may be heat treated to shrink the plastics tube 12, after removal from the mould. |
