| 摘要 |
A channel (1; 6; 7) adapted to be attached to a building structure comprises a pair of lips (2) defining a slot (3) therebetween and a back portion (4) having a rounded cross-sectional profile. Preferably, the back portion (4) has an half-elliptical profile. This channel (1; 6; 7) is adapted to form a channel assembly with a fixing (17; 27; 33 to 40) co-operable therewith. In one embodiment the fixing (27) comprises a dome-shaped head (28) constructed from a circular profile with flats (29) on opposite sides thereof. Preferably, the dome-shaped head (28) is made up of a series of radii that define part of an ellipse. Preferably also or in a another embodiment, the fixing (17; 27) comprises profiles (24, 25, 26) that are stepped inwardly of opposite edges of the head (18; 28) between the flats (22; 29). These profiles locate and bear against opposite edges of the lips (2) when the head is rotated within the channel. |
