drilling rig,land drilling rigs,drilling rig equipment Model:ZJ30L, ZJ40L, ZJ40L,ZJ70 Description 1)There are several drive modes, such as diesel + hydraulic torque converter (or hydraulic coupling gear box) + chain drive compound , diesel + parallel operation with narrow V-belt etc, the power distributing and utilizing reasonable and high efficiency.2)Hydraulic disk brake or band brake is used ...