Thermoplastic container having a ring-shaped reinforcing zone at its bottom
US4991734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 1989 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Aug 3, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/716
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A container (30d) of polyethylene terephthalate or similar thermoplastic material has a container body (32d), a mouth portion (37d) and a central bottom part (34d). The central bottom part consists of chiefly amorphous and/or thermocrystallized material and forms a bulge directed towards the interior of the container. A ring-shaped or band-shaped standing surface (36d) is arranged adjacent the transition of the bottom part into the container wall (32d). Adjacent to the standing surface the container has a circumferential area of material (35d) which through stretching and/or reshaping has undergone flow and through heating has acquired built-in stresses which tend to contract it. The surrounding circumferential area of material prevents the inward bulge of the central bottom part from straightening out and/or turning inside out when the pressure in the container is increased and/or when the temperature of the container material is raised. The invention also relates to a method and a device for achieving the container.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.