Edge gated injection molding system with hollow seals
US4344750A · kind A · utility
Inventor
Key dates
| Filing date | Apr 2, 1981 |
| Grant date | Aug 17, 1982 |
| Priority date | — |
| Expiry date | Apr 2, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/2761
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention relates to an edge gated injection molding system. An electrically heated sprue bushing is seated in a well in the cavity plate with a centrally extending melt runner passage which branches radially outward with separate channels leading to a number of edge gates in the cavity plate. An air gap is provided to insulate the hot sprue bushing from the surrounding cooled cavity plate and a hollow seal is provided at each gate to convey the melt across the air gap. Each seal is in alignment with one of the channels and one of the gates, and has its inner end seated in a recess in the sprue bushing and its outer end abutting against the curved wall of the cavity plate. The outer ends of the seals are dome shaped so that they are slightly resiliently deformable. A portion of the wall of the cavity plate is slightly inwardly tapered so that at the gates, the effective combined diameter of the sprue bushing and the seals is slightly larger than that of the well. Thus, when the sprue bushing is inserted into the well, the seals are slightly deformed against the wall of the cavity plate. When the sprue bushing is heated to operating temperatures, further deformation occurs, whi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.