Abstract: The present invention is directed to a window assembly comprising (a) a frame having opposed, vertical jambs with an upper sash guide rail, joined at their ends to the ends of opposed, horizontal top and bottom members forming, respectively, a header and a sill; (b) an upper and lower window sash, with the upper sash having stiles extending into the guide rails in the jamb to enable vertical sliding movement of the upper sash in the frame; (c) a parting rail mounted to the upper portion of each jamb in a channel adjacent to the upper sash guide rail to retain the upper sash within the frame, each parting rail having a longitudinal dimension about equal to the longitudinal dimension of the upper sash; (d) a parting rail spring means mounted in each channel to push the parting rail away from the jamb and towards the sash to hold the upper sash in place; and (e) a parting rail activator mounted on the upper outer edge of each upper sash; wherein the parting rail activator engages the parting rail when the upper

Abstract: A window sash formed preferably of plastic and having a pair of horizontal upper and lower rails and vertical stiles. The rails and stiles are extruded to form a principal outside edge wall for the sash and a plurality of additional walls and bosses within each of the rails and stiles perpendicular to said outside wall, including a pair of walls forming a channel with said outside walls. The stiles and rails are diagonally cut at the ends to form a miter joint. The miter joint is integrated by a single screw passing at each corner from the rail into the stile. One or more of the bosses and walls within the rail forms a support for the screw at each corner which will prevent angling of the screw. Each of the stiles has at least one boss for receiving the screw, said boss extending longitudinally of the stile. The single screw at each corner is therefore anchored against any angling both with respect to the rail and the stile and thereby forms a secure, non-slip miter joint.

Abstract: A window frame of extruded material having vertical members including sash guides wherein the vertical members are identical but reversed with respect to each other and in mirror-image relation; the sill and header are identical but inverted and reversed end for end with respect to each other. Each frame may be constructed of an identical pair each of two different members. The sill slopes downwardly toward the exterior of the frame. The sill and header are notched at right angles to the outer and inner surfaces to form corner seams which carry out the horizontal lines of the window frame and which do not require exact and difficult mitering to obtain a perfect seam. Such joints do not open during shipping and handling as do miter joints. The sash frame elements are made from a third extrusion. The vertical members and the sill and header are provided with sash supports in which the outer sash edge rides against an end wall of a vertical channel which faces into the window.