Tamper evident closure
US5190175A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 10, 1992 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Jun 10, 2012 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB65D55/026
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
In accordance with the present invention, an irreversible tamper evident system for a closure such as a button closure is provided. The irreversible tamper evidence system is provided by an appearance change system carried by the flexible button portion of the closure. The appearance change system comprises a liquid crystal material and a liquid crystal poison. When the button is depressed such as upon initial closure of the container, the liquid crystal material is separated from the liquid crystal poison and optical properties of the liquid crystal material are viewable. When the container is opened the flexing the button forces the liquid crystal poison into contact with the liquid crystal material and the optical properties of the liquid crystal material are irreversibly altered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.