| 摘要 |
An extruded aluminium beam has an upper inverted top hat portion (12), a centrally located web (14) and a base portion (16) in which there is a centrally disposed channel (32) for receiving a head of a bolt and outwardly extending base flanges (38). A pair of downwardly extending flanges (40) are formed at the outer ends of the top hat flanges (24) and a pair of upwardly extending flanges (42) are formed at the outer ends of the base flanges (38). The heights of these downwardly and upwardly extending flanges (40, 42) are equal. The minimum thickness of the top hat flanges (24) is greater than the minimum thickness of the base flanges (28) and the thickness of each of the inwardly extending flanges (34) which go to define the bolt slot (32) is greater than the minimum thickness of the base flanges (38). <IMAGE> |
