... 2-)High strength steel structures,smoothly lift up and drop down, easily operated,few faults. 3-)Moving ... sources: local power available at the working sites(110V,220V,380V,415V),diesel engines and generators 5-)Working ... 12m,14m,16m,18m,20m Control 1)Electrical up-down control device, or manual hydraulic pump device ... be realized at each control point. Lift Up,Stop and Lower could be realized at each ...