Method for forming an annular groove in a thermoplastic pipe
US4107249A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 1976 |
| Grant date | Aug 15, 1978 |
| Priority date | — |
| Expiry date | Mar 12, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/218
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An annular groove is formed in the periphery of thermoplastic pipe near an end thereof by combining the forces of a fluid under pressure and a rigid expandable core mold. A pipe is heated, softened and placed over a core mold having an extensible portion. The extensible portion is in the retracted state initially and presents no obstacle to the placement of the pipe on the core mold. A space is provided internally of the pipe and is sealed by parts of the core mold whereby the application of a fluid pressure pushes outwardly on the inner periphery of the pipe. At the same time or subsequently the extensible portion of the core mold is extended to provide additional pressure to and to shape the latter internal periphery of the pipe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.