Window assembly with upper sash rail stiffening member supporting tilt latch bolts

A window assembly comprising

• a main frame including two vertical main frame members rigidly connected by an upper and a lower horizontal main frame members with said vertical main frame members including horizontally spaced opposing vertical guide walls,
• at least one sash frame having elongated vertical sash frame members rigidly connected by elongated horizontal sash frame members and enclosing a glazing unit, with said sash frame supported by said vertical main frame members for vertical movement between open and closed positions,
• all of said main frame members and all of said sash frame members comprising a rigid plastics material,
• an upper said horizontal sash frame member including spaced vertical side walls connected by a horizontal top wall and a horizontal intermediate wall, with all of said walls cooperating to define a longitudinally extending internal cavity extending horizontally between said vertical main frame members,
• an elongated metal reinforcement channel extending continuously within said cavity from outer vertical side surfaces of said sash frame 30 and having a uniform C-shape cross-section formed by a horizontal bottom wall integrally connecting opposite vertical side walls with opposing horizontal top return flanges projecting inwardly from said side walls and defining a longitudinal continuous top opening,
• said bottom wall, said side walls and said return flanges of said channel extending continuously the entire length of said channel to said vertical main frame members and defining within said channel an undercut cavity with said channel having a horizontal width substantially greater than its vertical height,
• an elongated tilt latch reinforcement bolt having a horizontal width substantially greater than its vertical height and supported for horizontal sliding movement within each of the opposite end portions of said channel with each said tilt latch bolt substantially filling said undercut cavity and biased outwardly by a compression spring within said channel to engage one of said vertical guide walls, and
• a tilt latch bolt actuator slidably mounted on each end portion of said upper sash frame member with each said actuator including a member projecting downwardly through said top opening of said channel and connected to the corresponding said tilt latch bolt.