Gas-assisted injection molding of hollow ribbed article
US5401459A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1992 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Oct 5, 2012 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65D2519/00407
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
Improvements in articles, made by gas assisted injection molding of polyethylene and other materials, such as large arch shaped subsurface leaching conduits, and the processes by which they are made, are disclosed. The improvements involve control of which portions are hollow and which are solid, and include a stepped rib, where the thinner upper rib portion is solid and the wider base is hollow; articles having corrugated surfaces strengthened by ribs on both sides, where the hollows of the opposing side ribs are connected through holes in the undulating walls; articles having ribs which are narrowed where they are solid, compared to their width where they are hollow; and, articles having thinned wall regions surrounding sprues, to avoid undesired hollowing during injection molding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.