| 摘要 |
The base comprises two inverted 'U' shape tubular members (8, 12) which pivot into line to retract. The post (2) projects from the centre of the top base member (8), is guided in a square section tube (11) which is mounted above the lower base member (12), and a system of lug stops (22, 23) maintains the base members in the alternative relationships. The guide tube (11) is mounted on two vertical bars (15, 16) which extend from diagonally opposed corners to the lower base member (12). The latter also has two vertically projecting lug stops (22, 23). The lugs (22, 23) and the guide supports (15, 16) are staggered along the lower base member (12), and the distance (19) between the guide (11) and the lower base member (12) is equal to more than twice the external dia. of the base members (8, 12). |
