Cylinder lock combination, a lock cylinder and a key for such a combination
US4507944A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1981 |
| Grant date | Apr 2, 1985 |
| Priority date | — |
| Expiry date | Dec 30, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T70/7904
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A cylinder lock-key combination includes a cylinder housing (1) having arranged therein a rotatable cylinder plug (2) having a slot (3) for a key (8). Arranged on the spine of the key is coded information in the form of regions (8a, 8b) of mutually different magnetic permeability. When the key moves relative to the housing these regions cause variations in a magnetic flux generated by a magnetic body (5k) and passing the key slot (3). A differential field plate (5) arranged in the housing and incorporated in an electric circuit, which also incorporates a bridge coupling, is arranged to convert said magnetic flux variations to momentary changes in resistance in the electric circuit, causing the bridge coupling to become unbalanced so that an electric pulse train corresponding to the coded information is generated in the circuit. This pulse train is sensed and evaluated by means, for example, of a data processing device. The invention also relates to a cylinder lock and a key for said combination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.