... groundwork reinforcing engineering in urban construction site, for blowing up engineering or blowing up hole etc. Alternating of the drilling rig can ... lower in the central so that moving of drill tolls up-and-down is very convenient.4)Total hydraulic control with ... /min,Forward or reverse): 20,40,56,60,111,167Rated pull up force (kN):25Rated feeding force (kN):17Feed stroke length (mm ...