Vent type injection molding machines
US4822269A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1987 |
| Grant date | Apr 18, 1989 |
| Priority date | — |
| Expiry date | Aug 20, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In a vent type injection molding machine of the type comprising a heating cylinder, injection nozzle means having a vent port and connected to the front end of the heating cylinder and a reciprocatable screw for metering a predetermined quantity of resin to be injected, the injection nozzle means comprises a first injection nozzle connected to the heating cylinder, a second injection nozzle coaxial with the first injection nozzle, a spring for urging the second injection nozzle against a stationary metal mold and a housing surrounding the first and second injection nozzles. The vent port is provided through the housing at a point communicating with a space in the housing between the first and second injection nozzles. The operation of the injection molding machine is controlled by a method comprising the steps of metering a predetermined quantity of molten resin to be injected by advancing the screw, closing the vent port and the injection nozzle means, retracting the screw thus forming a space in the injection nozzle means, and discharging the gases of volatile substances and moisture contained in the molten resin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.