US Patent 7296832 Locking mechanism for door hinge

A locking mechanism for hinges, which includes a butt hinge of the type securable between a door frame jamb and a door stile, having first and second leaves moveable along a common axis; upper and lower loops formed along the upper and lower edges of the leaf secured to the door frame jamb, the loops extending over the leaf of the door stile when the door is in the closed configuration and the leaves abut one another; and a pin insertable into the upper loop and extending into the lower loop, defining a means for blocking the movement of the stile leaf when force is placed upon the door in order to attempt to open it. The leaves are free to open when the pin is removed.