Moulding device for manufacturing envelope of heicoidal bellows comprises a mould and core having complementary threading to delimit moulding space and the envelope and core are unscrewed for stripping of the envelope

摘要

The mould (2) threading (21) comprises a discontinuous rib (212) forming trough and crest with 5mm height/depth over the envelope and has circular section on both sides from which extend the flanks for retaining the envelope. The rib has plane surface of opposition perpendicular to the curve of the threading. Air is injected under pressure by channel between the core (1) and the envelope (3). Surface roughness of the mould is higher than core and is measured by sanding and chemical treatment. Independent claims are also included for: (1) manufacturing process by moulding; and (2) bellows envelope.