Maximum-security lock

Abstract

A lock assembly has a housing in which is provided a cylinder lock having a shell fixed in the housing and a plug rotatable in the shell by means of a key. A tongue is carried on and jointly rotatable with the plug and is formed with a plurality of bittings each engageable with a respective tumbler in the housing and displaceable into an aligned position. A locking element such as a bolt is engageable with the tumblers and is only displaceable between a locked and unlocked position when the tumblers are in the aligned position. The tongue is formed of a plurality of plates each constituting a respective one of the bittings. Thus even if the cylinder lock is forcibly ripped out of the assembly a tumbler-type lock structure is left within that cannot readily be overcome to allow operation of the locking element.

Dependencies are inferred from the claim text.