| 摘要 |
A support (10) has an inner part (12) teiescoped within an outer part (11) with one of said inner (12) and outer (11) parts having means to secure the part to a structure to be supported, the other of said inner (12) and outer (11) parts having a foot (13) for engagement with the ground, the inner (12) or outer (11) part having along its length a series of openings (17), each opening being capable of receiving an axle (18) of a cam means (20), the cam means (20) further including an eccentric cam (21) which acts on the outer or inner support part respectively, and lever means (26) to rotate the cam (21) and hence cause telescopic extension of the telescoped parts, locking means (27) being provided to prevent telescopic retraction of the parts (11,12) when the inner (12) and outer (11) parts are in selected relative positions, characterised in that the inner (12) or outer (11) part on which the cam bears has first (14) and second (25) abutments at positions displaced longitudinally of the support (10), and the cam (21) is engageable with the first (14) and second (25) abutments selectively. |
