Extensible beam

An extensible beam comprising:

• a first, elongate, element defining a channel therein, the first elongate element comprising:
• an upper portion which provides an upwardly facing surface to support materials above the beam, and first and second lateral portions which project generally perpendicular from respective opposing sides of the upper portion so that the upper portion and lateral portions define the channel;
• and respective first and second support portions which project inwardly from the respective first and second lateral portions;
• and
• a second element adapted to move, in the channel, relative to the first elongate element in order to vary the amount of overlap between the first and second elements and thereby vary the length of the beam;
• wherein the second element is in the form of a frame comprising:
• first and second generally parallel spaced apart elongate bars which form lateral sides of the frame and which slidingly engage the first and second support portions, respectively;
• a first cross member which extends between, and spaces apart respective first ends of the first and second bars, and forms a first transverse member of the frame;
• and a second cross member, spaced apart from the first cross member in the direction of elongation of the bars, which extends between, and spaces apart, the first and second bars and forms a second transverse member of the frame and wherein the first and second bars are separately formed pieces.