Search results
Results from the WOW.Com Content Network
Entrance to HM Prison Edinburgh. A mantrap, security mantrap portal, airlock, sally port or access control vestibule is a physical security access control system comprising a small space with two sets of interlocking doors, such that the first set of doors must close before the second set opens.
In firearms, a trapdoor is a form of breech-loading mechanism for rifles in which a hinged breechblock rotates up and forward, resembling the movement of a trapdoor. [1] The Springfield models 1865 and 1873 were best known for first employing this type of action.