Patent ID: 7144189

Claim:
A method of retrofitting a security cover to a ground opening that is fitted with an existing annular shroud having a wall with an inner surface and a shoulder that extends inwardly from the wall inner surface, comprising the steps of: a) providing second annular shroud and nesting the second annular shroud upon the existing annular shroud, the second annular shroud having a lid with a periphery, the lid being movably affixed to the second annular shroud with a hinge, the lid having an upper surface, and a lower surface; b) the lid having an interlocking structure spaced circumferentially about the periphery of the lid from the hinge, the interlocking structure including a lock having a locking member, the locking member positioned at the periphery of the lid, the locking member including a projecting portions that is rotatable between retracted and extended positions; c) using a key to interlock the interlocking structure with the assembly of nested annular shrouds by locking the lock, wherein the lid can be opened by using the key to unlock the lock and rotate the projecting portion to the retracted position.