Abstract: A round top window includes a flexible master frame member which is bent to the desired degree of curvature and then joined to a straight master frame member. A stop member is attached to the master frame members to provide support for a glazing assembly which is held in place by an elastomeric glazing bead. Nailing fins are provided on the round top window in order to facilitate attachment to the frame of a building structure.

Abstract: A window frame apparatus includes flat metal inserts which are inserted into hollow plastic members which form a frame. The metal inserts are disposed so that the direction of maximum resistance to bending opposes the direction of wind loading, thereby providing a light-weight yet relatively stiff apparatus.

Abstract: A window apparatus includes a jamb assembly and a pair of window frame assemblies which are capable of sliding relative to the jamb assembly for the purpose of opening and closing and also tilting inwardly to facilitate cleaning. Locking members are provided on the upper corners of each of the window frames. The locking members are lodged in slots formed in the window frames and project beyond the window frames to engage the jamb assembly and prevent tilting of the window frames. The locking members have a relatively low level of stress when the window apparatus is subjected to wind loads, thereby enabling the window apparatus to withstand relatively high wind loads encountered on the upper floors of large buildings.