EP 0780204 B1 20010905 - Process and apparatus for making moulded sleeve pipes
Title (en)
Process and apparatus for making moulded sleeve pipes
Title (de)
Verfahren und Vorrichtung zur Herstellung von Muffenrohr-Formlingen
Title (fr)
Procédé et dispositif pour la fabrication de tuyaux à emboîtement moulés
Publication
Application
Priority
DE 19547775 A 19951220
Abstract (en)
[origin: US5779966A] Particularly large-size bell and spigot pipes of ceramic molding material are isostatically pressed within a hollow-cylindrical pressure pot with a molding cavity for the molding compound. An inner core is axially extractable and an elastomeric diaphragm is disposed concentrically around the inner core. The diaphragm is clamped in place at its end face and there is defined between the pressure pot and the diaphragm a chamber which communicates with a source of hydraulic pressure. The inner core is provided with a molding ring on which the bell region of the bell and spigot pipe is formed. The molding ring has a reduced-diameter end region and thus defines two end faces. The two end faces are concentric but axially spaced apart. At least the upper end face of the molding ring is provided with a surface coating of elastic plastic material. An annular gap is defined between the end region of the molding ring and the inner core which, depending on the hydraulic pressure in the cavity, opens and closes a vent port which communicates with the molding cavity. Microcracks in the bell region of the molding can be safely avoided.
IPC 1-7
IPC 8 full level
B28B 3/00 (2006.01); B28B 21/18 (2006.01); B28B 21/36 (2006.01); B28B 21/76 (2006.01)
CPC (source: EP US)
B28B 3/003 (2013.01 - EP US); B28B 21/18 (2013.01 - EP US); B28B 21/36 (2013.01 - EP US)
Designated contracting state (EPC)
AT CH DE ES FR GB IT LI
DOCDB simple family (publication)
US 5779966 A 19980714; AT E205128 T1 20010915; DE 19547775 C1 19970731; DE 59607627 D1 20011011; EP 0780204 A1 19970625; EP 0780204 B1 20010905
DOCDB simple family (application)
US 77087396 A 19961220; AT 96120533 T 19961219; DE 19547775 A 19951220; DE 59607627 T 19961219; EP 96120533 A 19961219