US Patent 7107800 Door bolt

A door bolt is constructed to include a jam plate fixedly fastened to a doorjamb, and a doorplate assembly installed in the free end of a door panel and adapted to secure the free end of the door panel to the jamb plate, the doorplate assembly having a lock cylinder controlled by a key to move a movable frame bar in a fixed locating frame bar and to further move two locking straps relative to each other between a first position where the doorplate assembly is prohibited from escaping out of the constraint of the jamb plate and a second position where the doorplate assembly is released from the constraint of the jamb plate.