Keysafe system with timer/calendar features
US4988987A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1989 |
| Grant date | Jan 29, 1991 |
| Priority date | — |
| Expiry date | Jan 27, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T70/7028
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An electronic lock system is disclosed in which a key can be assigned a limited lifetime, such as by storing data indicative of an expiration date in a key memory. Whenever the key is used with a lock, the lock first examines this key data and verifies that the key is still timely before performing any operations. After a key's expiration date has passed, it is useless until a new expiration date is stored in its memory. By this arrangement, keys that are lost or stolen soon lose their efficacy and no longer pose a threat to system security. The invention also permits the lock administrator to issue keys with different useful lives, so that, for example, a person who needs a key for only one day can be issued a key that expires the next day. A variety of other operational features are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.