Abstract: This invention relates to a thermal window construction which comprises a fixed frame member and a movable frame or operating sash member. The window is characterized in that the operating sash member includes an outwardly facing glazing surface to which a pane sub-assembly comprising two or more glass lites are connected, the bond between the pane sub-assembly and operating sash being provided by a bead or quantity of silicone interposed between an inwardly directed surface of the sub-assembly and the glazing surface through a laterally open channel, whereby complete filling of the said space may be assured. The overlapping areas of glass and metal bonded by the silicone rubber material are coordinated with the glass expanse and weight in such manner that the stress applied to the bonded areas will not exceed about 20 p.s.i.

Abstract: The present invention is directed to an insulated window assembly including a fixed frame adapted to be installed in a building structure and a movable, pane carrying operating sash mounted on the fixed frame. The invention is characterized by the provision of a novel seal structure defined between the fixed frame and outer pane member, said seal being formed laterally interiorly of the glazed connection between the pane and sash whereby leakage between the fixed and moving frames is effectively blocked, the seal also protecting the said glazed connection. Where used in conjunction with a metal framed window device, the assembly provides protection against heat loss comparable to that provided by conventional thermal break windows, without the attendant disadvantages thereof.