Window sash assembly

Claim 1

A window sash assembly for installation in a building window opening which comprises an outer metal sash, an inner sash positioned and assembled indoors adjacent to said outer sash and a peripheral edge member positioned about the inner end of said inner sash to cover the adjacent open end of an indoor wall member, characterized in that said inner sash includes a main portion of adiabatic material which is integrally formed with said peripheral edge member at the inner end portion thereof and forms a sash main frame composed of similar upper, lower, right-hand, and left-hand frame members and extending from said peripheral edge member to the indoor pieces of said outer sash and metal upper and lower rail frames and metal left-hand ad right-hand door boxing frames being disposed along the inner periphery of said sash main frame, said sash main frame being formed into a first framework and said upper and lower rail frames and left-hand and right-hand door boxing frames being formd into a further framework, said further framework being separately mounted within and connected to said first framework to form a one-piece framework assembly which is fitted as a unit in said building window opening.