Extrusions and building structures

A window-like structure comprising:

• a plurality of rigid side and end members secured together in perpendicular and parallel relationship to form a frame and arranged to be secured to a building structure, the ends of said members being mitered and united together, each of said members of said frame being formed with channels which combine to form a channel positioned around the periphery of said frame, said channel including teeth projecting inwardly from its sides;
• a sheet of flexible plastic material spreading over all of said side and end members;
• a plurality of locking members, one of which is inserted in each of said channels, forcing a portion of said flexible sheet into said channels and stretching, sealing, holding, and locking said sheet to said frame in said channels;
• said locking members being each formed as a one piece extrusion having a generally T-shape in cross section with a stem and a head both of which are formed of substantially rigid plastic material and which has both sides of the stem of the T provided with integral spaced angularly and outwardly extending projections of plastic material substantially more flexible than the substantially rigid material of the main section of the T and integrally united with the substantially rigid material of the main section of the T, said projections having a thickness less than the stem and being inclined from the stem toward the head;
• the width of the channel between the crests of the teeth being less than the width between the outer ends of the projections, the teeth and projections combining to lock the sheet in place.