ROERSTYKKE, FORTRINNSVIS AV BETONG, FORSYNT MED TETNINGSRING AV GUMMI ELLER ANNET GUMMIELASTISK MATERIALE

摘要

1409072 Moulding pipes with sealing rings FORSHEDA IDEUTVECKLING AB 23 Oct 1972 [25 Oct 1971] 10180/75 Divided out of 1409071 Heading B5A A mould cavity for a pipe is defined between an outer mould (dotted in Fig. 3), a mandrel and base 30, 32, a sleeve 36 and a sealing ring 4 held in a recess defined by the sleeve 36 and mandrel 30 together, or by the sleeve 64 alone (see Fig. 6). Concrete is cast in the cavity, and the mandrel 30 and sleeve 36 sequentially removed after hardening of the concrete to leave the sealing ring 4 in position. The sleeve 36 and sealing ring 4 (or 66) are made of rubber and are differentially stretched on to the mandrel 30 so that the sleeve 36 contracts most on mandrel removal, away from the pipe and sealing ring. In Fig. 3, an extension 6 of the sealing ring is irremovably embedded in the pipe, but Fig. 6 shows a removable ring. Alternative shapes of sealing ring are described (see Division F2).