Cylinder lock with permissible service entry
US4631941A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 20, 1984 |
| Grant date | Dec 30, 1986 |
| Priority date | — |
| Expiry date | Dec 20, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T70/7944
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A cylinder lock (1) has a normal locking mode (12 o'clock position) and a service locking mode (10 o'clock position). When the cylinder plug (3) is left in the service mode of the lock, with the aid of a standard key, the lock can be turned with the aid of a service key (9). The service key is latched against withdrawal in the normal mode of the lock, by means of an intermediate pin (7') of larger diameter than a corresponding upper pin (4) in the normal mode of the lock. The intermediate pin can be received in a widened part (3b') of a corresponding pin-channel (3a') in the cylinder plug, but is unable to enter the pin channel (2a) of the cylinder housing of smaller diameter, hence latching the service key (9). Subsequent to using the service key (9), the cylinder is returned to the normal locking mode (12 o'clock position) with the aid of the standard key, whereafter the lock can only be opened with the aid of the standard key. Each of the two modes can be defined by a spring-biased ball disposed in a suitable pin-channel and arranged to snap-in a corresponding empty pin-channel in the plug.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.