Method and an apparatus for the extrusion of plastic pipes
US4865797A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1988 |
| Grant date | Sep 12, 1989 |
| Priority date | — |
| Expiry date | Aug 19, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2023/186
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a method and an apparatus for the extrusion of plastic pipes. Today, plastic pipes are provided with a sleeve in such a manner that the end of the pipe is heated, whereafter the end is expanded by means of a mandrel or a pressure medium. This step requires a separate sleeve machine, and it also takes plenty of time and consumes thermal energy. According to the invention a sleeve (22) is formed in connection with the extrusion of a pipe in an apparatus in which a mandrel (8) is surrounded by chill moulds (1, 2) moving in the axial direction of the apparatus. The sleeve is formed by providing some of the chill moulds with a recess (16) the shape of which corresponds to that of the sleeve (22) and by pressing a plasticized plastic hose (11) extruded through a nozzle (10) against the walls of the recess in the area thereof by means of pressure air.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.