Apparatus and a method for the production of ribbed pipes
US4867928A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Apr 28, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/9115
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention relates to an apparatus and a method for the production of outwardly ribbed, plastic pipes. The apparatus includes a core around which a plasticized material is pressed from a nozzle. A kernel having an essentially constant diameter is positioned at the terminal end of the core for a smooth inner face of the pipe. The outer face of the pipe is ribbed by grooves of axially displaceable chill moulds. The end zone of the kernel is provided for the cooling of the inner face of the pipe. In known apparatuses the grooves of the chill moulds are often filled incompletely and the inner face of the pipe becomes uneven on account of air bubbles, for instance. These disadvantages are avoided by heating an initial zone of the kernel for heating the inner face of the pipe and by shaping the surface of the initial zone to slightly expand conicallly in the production direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.