... efficiency.2)Hydraulic disk brake or band brake is used as the main brake of drawworks, the assistant ... is equipped with auxiliary drive device which can be used for mast lifting and laying down, also for ... bevel gear box and cardan shaft.drilling rig,land drilling rigs,drilling rig equipment....Parameter Model, drilling rig ZJ30L ZJ40LZJ50LZJ70LNominal drilling depth, 127mm(5)DP, m30004000500007000Max ...