Patent ID: 7241352

Claim:
A method of making an insulating window sash comprising: providing a plurality of sash sections, each sash section comprising a first end, an opposite second end, a first side, an opposite second side, a third side between the first and second sides, and a fourth side between the first and second sides and opposite to the third side, the second side having a first groove extending from the first end to the second end and adjacent the fourth side and a second groove extending from the first end to the second end, spaced from the first groove and adjacent the third side, the base of the first groove spaced a greater distance from the first side than the base of the second groove, a first sheet supporting surface aligned with the first groove and a second sheet supporting surface aligned with the second groove and an edge of the first sheet supporting surface spaced a greater distance from the first side than an edge of the second sheet supporting surface; positioning the plurality of sash sections relative to one another with the first end of the plurality of sash sections facing and spaced from the second end of an adjacent one of the plurality of sash sections, the first sheet supporting surface of each one of the plurality of sash sections generally aligned with one another and the second sheet supporting surface of each one of the plurality of sash sections generally aligned with one another; providing a first sheet and a second sheet, each of the sheets having similar peripheral configurations with the first sheet having a peripheral dimension less than the peripheral dimension of the second sheet; supporting portions of the marginal edge of the first sheet on the first sheet supporting surface of the plurality of sash sections and portions of the marginal edge of the second sheet on the second sheet supporting surface of the plurality of sash sections, and moving the sash sections toward one another to move the first end and the second end of adjacent ones of the sash sections toward one another and portions of the supported marginal edge of the first sheet into the first groove of the sash section and portions of the supported marginal edge of the second sheet into the second groove.