Plastic closure with safety button and method of forming same
US5033633A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 12, 1990 |
| Grant date | Jul 23, 1991 |
| Priority date | — |
| Expiry date | Jan 12, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2031/565
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This relates to the formation of a vacuum indicating button in a molded plastic closure. The button is formed by cold working which results in the flow of plastic material from a central portion of the end panel towards the center of the central portion and the automatic formation of an upwardly projecting generally curved button. In all forms the button is formed by cold working of the plastic. The button may be formed by coining between two opposed tools, or the button may be formed by cold working only the top side of the central portion of the end panel by such methods as including spinning, mechanical peening and shot peening. In the case of coining, the button may be formed either by a single annular ring of cold worked, oriented, reduced thickness material or by a plurality of such rings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.