Apparatus for producing hollow plastic objects with pressurized gas injection after overflow cut-off
US5928677A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Oct 30, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/173
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An apparatus for producing plastic objects with hollow spaces is disclosed. The method has the following steps: establishing a fluid connection (9) between the main cavity (2) of a mold (1) and an overflow cavity (8) and injecting a sufficient amount of plastic melt into the cavity (2) of the mold (1) along a melt flow path, which extends from a plasticizing unit (4, 5) through a plastic injection nozzle (3) into the mold (1), such that plastic melt passes from the main cavity (2) into the overflow cavity (8). The fluidic connection (9) between the main cavity (2) and the overflow cavity (8) is then broken-off prior to the introduction of a pressurized fluid, especially a pressurized gas, into the melt in the cavity (2) by at least one fluid injection nozzle (7), so that the melt situated in the cavity (2) is distributed in the cavity (2) while forming a hollow space, and is pressed against the cavity walls of the mold (1). The thus formed molded part is then allowed to cool down to a temperature below the melting point of the plastic melt, the cavity pressure is relieved, and the molded part is removed from the mold. The method advantageously achieves the result that the produced …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.