| 摘要 |
A guard system for door locks mainly used in metal doors. The guard system comprises two elongated registering plates applied on both sides of the door around the door lock and secured together by means of through bolts. At least one of the plates has a key hole registering with the key hole of the lock barrel and an elongated slot at the inside face of the plate receiving an elongated protruding portion of the lock barrel to positively prevent rotation and unscrewing of the lock barrel. The plate on the door opening side has a tongue overlapping the joint between the door frame and the door itself to prevent access to the lock bolt. The plate on the opposite side of the door has a tongue inserted between the door and the door stopper, in the closed position of the door, to prevent removal of said plate by an unauthorized person locked inside the premises. Preferably, one or the other, or both of the plates, form a handle to open the door. The system considerably diminishes the possibilities of tampering with the door lock mechanism.
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