... work on 2-)High strength steel structures,smoothly lift up and drop down, easily operated,few faults. 3-)Moving method:4 wheel ... ,8m,10m,12m,14m,16m,18m,20m Control 1)Electrical up-down control device, or manual hydraulic pump device when the electricity ... different floors could be realized at each control point. Lift Up,Stop and Lower could be realized at each control point ...