Security lock with spring-loaded locking-bits - has bits allowed to move onto contoured web of key after preliminary key rotation

摘要

The security lock has elastically constrained locking pits (109). The bits move into place to follow the configuration of the cut radial webs of a key and to authorise the rotation of a hollow shaft (59). A preliminary rotary movement of the key is necessary before movement of the bits (109) is authorised. The arrangement reduces wear of the bits. The lock incorporates a mechanism which connects the shaft (59) to a fixed mounting-plate (22). When the key is first inserted the bits (109) remain remote from the cut edges of the webs of the key. A key rotation of approx. 12 deg. effects the release the bits which are displaced by springs to make contact with the key.