door becomes brl and antintrusione when ring a bell, and open its door protected by a grating set

摘要

the found includes, in combination, a door that opens and closes normally, made it a little door, a grate to be set on the outside of the door.preventing strangers can come in when we open the door to give us communications, deliver mail or small packages.and an original mechanism which as we open the door to lock the door and unlock the door only when it's close.characteristic of the invention is advantageous.when we open the door to strangers who rang the bell if these through the grate are threatened with a gun (false messengers, fake cops) etc.will not the same access because we can't open the door, blocked by the mechanism until it's close totally the little door.