Method and apparatus for producing plastic objects with solid sections and hollow sections
US5776412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Jul 10, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C45/1711
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method and an apparatus are disclosed for producing plastic objects with solid regions and hollow regions. The method has the following steps: a) blocking off a part of the cavity (2) of a molding tool (1), so that little or no plastic melt can reach the blocked-off region (8); b) injecting plastic melt into the unblocked region (9) of the cavity (2) of the molding tool (1); c) releasing the blockage, so that plastic melt can reach the previously blocked-off region (8) of the cavity (2); d) injecting a pressurized gas into the melt by means of at least one fluid injection nozzle (7), so that the melt injected into the molding tool is distributed into the desired regions of the cavity (2) while forming a hollow space and is pressed against the cavity walls of the molding tool (1); e) allowing the molded part (6) to cool; f) relieving the cavity (2) of the pressure of the pressurized fluid; and g) demolding the molded part. The advantage achieved thereby is that solid regions and hollow regions are formed in the molded part in a predetermined manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.