摘要 |
A base structure for a mobile access platform includes a chassis (10) having at least two pairs of wheels (12, 16a, 16b), at least a first one of the pairs of wheels (16a, 16b) including a suspension mechanism including, for each wheel, a swing arm member (18) on which the wheel is mounted, the swing arm member (18) being arranged to pivot about a substantially horizontal pivot axis, a stop member (21) arranged to engage the swing arm member (18) so as to limit upwards movement thereof, and a biassing mechanism (24) arranged to exert a biassing force on the swing arm member (18) to urge the swing arm member upwards towards the stop member (21). The biassing force is less than the force needed to maintain the swing arm member (18) in engagement with the stop member (21) when the wheel is unsupported. The arrangement is such that the swing arm members (18) normally engage the stop members (21) when the mobile access platform is standing on flat, level ground.
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