Pressure-responsive security alarm
US4837555A · kind A · utility
4Cited by
2References
7Claims
0Family size
Inventor
Key dates
| Filing date | Jul 12, 1988 |
| Grant date | Jun 6, 1989 |
| Priority date | — |
| Expiry date | Jul 12, 2008 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE05G1/10
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Apparatus is provided to evacuate an air-tight openable and closeable container to a sub-atmospheric pressure. A flexible diaphragm inside the container responds to a change in pressure to actuate an alarm. In one embodiment, a display case is evacuated via a one-way valve by connecting a pump thereto. In a different embodiment, a pump inside a hand-carried case evacuates the case via a one-way valve. Alternatively, at least one side of the case is flexible enough to evacuate the case by pushing thereon, with no pump being required.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.