Opening covering for building opening and headrail thereof

The headrail has a longitudinal frame 10' with two subframes 16' and 18' and a fixing member 20' which bridges the two subframes and connects them together. The subframes may have top boards (figure 4 A 162 and 182) where two ends 22' and 24'of the fixing member attach. There may be a connecting part (figure 4A 30) which attaches to an inner wall of the frame and the frame may have a hook (figure 4A 108) on the top surface which fits into a shape the fixing member. The fixing member 20 may have indents or recesses and projections (figure 11 222' and 242'). The rail may also have a track 40 which is in two parts 44' and 46' that may be connected by a linking rod (figure 6 48) and the cross-sectional shape of track may be non-circular. The frame may have detachable supports 50 which aid in assembling the track and which fit into a groove in the frame.