| 摘要 |
A concrete block (5), installed flush with ground level in a carriageway or pavement (4), has a central vertical hole accepting the casing (3), its flange (16) overlapping the block. The bollard (1), slides on slip liners (12) within the casing. When fully retracted its base rests on a stop (19) while its top (2) is flush with the casing flange. The pantograph (7) end links are connected, via common pivots, to one tongue projecting under the bollard top (10) and to another (9) on the casing bottom. These pivot points, with the center pivots on the intervening linkage, lie on the bollard's vertical axis (Z,Z'). The pantograph is extended, pushing up the bollard, and retracted to the flush position, by an e.g. electro-hydraulic actuator (8) connected between the base pivot (9) and an intermediate center pivot on the pantograph. To reduce the effort on raising, springs (111) are fitted across e.g. 2 pairs of outer pantograph pivots. The casing has a drain (15) and an electrical cable entry (13).
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