Window frame assembly with frame shaped locking member

A window frame assembly comprising:

• (a) a first intermediate frame comprising a plurality of longitudinally elongated first frame lengths which butt and are secured at opposite ends to form corners of the first intermediate frame, said first intermediate frame being adapted to be inserted within a window opening in a close fitting relationship and having a flange on one side thereof for bearing against a peripheral edge of the window opening to prevent direct passage of the first intermediate frame through the window opening, locking channel formed in and extending about the periphery of the first intermediate frame, said locking channel being arranged to be accessible from the other side of said frame when the first intermediate frame is mounted in a window opening,
• (b) a second intermediate frame comprising a plurality of second frame lengths which butt and are secured at opposite ends to form corners of the second intermediate frame, each of said lengths being coextensive with a corresponding length of said first intermediate frame, each of the lengths of the second frame having a one-piece locking tongue formed integrally therewith and projecting therefrom each tongue being adapted to be inserted within the locking channel of its associated first frame member, the locking tongues of each second frame length extending continuously along a major portion of the length thereof and being spaced a short distance from one another at the corners of the second intermediate frame so as to be independently flexible to facilitate the insertion of the locking tongues within the locking channels when the second intermediate frame is interconnected to the first intermediate frame.