Security lock and seal for double door or window installations

Abstract From the Canadian patent

Conventionally, individual doors of a double door installation, are secured separately within the frame either with conventional lock sets or dead bolts or the like and often the outer or storm door adds little to the security of the installation against break in . The present device provides means to secure the two doors together from the inside, either separate from or integral with a lock assembly for the outer door. An internally or externally screw threaded element is provided on the inner surface of the outer door selectively engageable by a rotatable screw threaded element on the inner door which may be screw threadably engaged with the outer door element when both doors are closed. …