| 摘要 |
Extruded frame elements include a pair of opposed parallel jambs, a sill, and a header. A selected pair of opposite frame elements each contain a longitudinal channel; and metal, beam-like reinforcing members within these channels. The other two frame elements may also have reinforcing members. The sill is stepless and has a generally uniform, inside-to-outside downward slope. An upward-projecting lip on the sill, and a downward-projecting lip on the lifting ledge of the lower rail, have engaging surfaces which limit the outward deflection of the lower rail under tornado (low pressure) conditions. A pair of wind load stop elements project into the window opening from the jambs, adjacent the outer surfaces of the stiles of the inner sash unit. The inner sash has a hurricane stop element on each of its stiles, projecting sideways, so as to engage the jambs and limit the inward deflection of the stiles under hurricane (high pressure) conditions. Each rail and stile in each sash may have arms which extend on either side of the window pane assembly and contact the two panes at holding surfaces of the arms. A chevron-shaped longitudinal channel may be defined adjacent to the holding surface of each arm, and a corresponding adhesive key may be formed on each pane and engage the corresponding channel.
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