Injection moulding apparatus
US4740150A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1987 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | May 12, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/1729
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Apparatus for producing an injection moulding of plastics material comprises means for introducing a supply of plastics material, passage means for communicating the supply means to a mould space, and means for introducing a pressurized gas into the plastics material filling the mould space whereby the gas creates a gas containing cavity in the plastics material and for thereafter relieving the gas pressure within the gas containing cavity before the mould is opened. The gas supply/pressure relieving means comprise valve means including a valve port opening directly into the mould space, for opening the gas filled cavity to the atmosphere, a valve member for closing the port, and means to supply pressurized gas to the mould while the valve member is in the port closing position to create the cavity and to maintain the valve port open to the cavity whereby, after a moulding operation has been finished, the supply of pressurized gas can be terminated and pressurized gas in the cavity in the moulding can be vented to atmosphere by opening the valve member.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.