Method for the formation of a hole in a plastic pipe
US4873048A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1988 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Jul 7, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/119
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method of forming a hole in a plastic pipe feeds a plastic layer for the plastic pipe from a nozzle about a mandrel into chill moulds being displaced along an elongated mould cavity about the mandrel formed by the chill moulds. All of the plastic layer is pressed into the chill moulds with a pressure medium between the mandrel and all of an inner surface of the plastic layer for forming the plastic pipe therefrom. Only portions of the plastic layer of the plastic pipe are then subjected to a local pressure difference exceeding the breaking limit of the plastic layer between the inner surface and an opposite, outer surface of the plastic layer at least in part from a flowing medium for forming a hole in the plastic layer of the plastic pipe, the flowing medium being one of a gas and a liquid and flowing from the mandrel at a pressure higher than that of the pressure medium pressing the plastic layer of the plastic pipe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.