Two=stage moulding of rubber inserts between concentric metal bodies - to suppress delamination or distortion by differential thermal stresses

摘要

A rubber insert to link two concentric metal bodies, is made in two stages by (a) moulding on to the smaller body a rubber cover having projections such as longitudinal ribs. After replacing the mould shell with the second metal body, the space between the second body and the cover moulded on to the first body is filled with more rubber moulded to bond to the inner face of the outer body. Used for producing rubber inserts in hinges etc. to suppress risk of delamination due to differential thermal expansion effects. The two rubber/metal bonds are produced separately without mutual interference and the complementary rubber layers are engaged both mechanically and adhesively. That adhesive stresses can be relieved without disengaging or distorting the metal components. More reliable than overpacking the mould cavity in a single shot to produce a compressive stress to counteract any subsequent thermal contraction.