The traditional way of unloading the rod of down the hole drill

The down-the-hole drill is mainly used in underground mines and tunnels, water conservancies, and other geotechnical projects to drill large-diameter deep holes in all directions. During the drilling process, the DTH hammer dives into the bottom of the hole next to the drill bit. When working, the DTH hammer releases wind energy to drive the drill bit to impact the rock. Some drill pipes are connected to the top of the DTH hammer, and the drill pipes are connected by tapered threads, as the drill pipes continue to advance and the hole is drilled deeper and deeper, it is necessary to connect and reconnect the rods frequently. What about the traditional way of receiving and unloading rods?

Rod receiving process

When connecting the drill pipes, first open the jaws above the rod unloader seat, and then move the other drill pipe (drill pipe to be connected) and place it on the rod unloader so that the upper and lower drill pipes are concentric, and the rotary head spindle and the drill pipe to be connected are concentric. Operate the rotary head motor on the guide rail for positive rotary motion, and operate the guide rail propulsion cylinder to make the rotary head motor move down freely and slowly to complete the docking of drill pipe and drill pipe, and the docking of drill pipe and motor spindle.

Rod unloading process

Operate the propulsion cylinder, lift the rotary head motor, so that the drill pipe to be disassembled is exposed from the blast hole, and lifted it to the position where the joint surface of the two drill pipes can be clamped by the upper and lower clamping cylinders of the rod unloader respectively, and clamp them separately, drive the rod unloading cylinder, the upper and lower clamping cylinders can turn at a certain angle relative to each other to realize the loosening of the threaded joint between the two drill pipes. The two drill pipes are completely unthreaded and thus separated.
Operate the upper clamping cylinder to clamp the drill pipe to be dismantled again, reverse the rotation of the rotary head, loosen the threads of the drill pipe to be dismantled and the spindle of the rotary head, operate the propulsion cylinder to lift the rotary head to the top of the guide rail, then release the upper clamping cylinder and the drill pipe can be removed.

Set the float to avoid damage to the thread of the rock drilling tools during the process of manually receiving and unloading the rods

When the rotary head motor tightens or loosens the rock drilling tool threads during the process of receiving and unloading the rod, the two mating rock drilling tools are bound to produce relative displacement in the direction of the axis, and the rock drilling tools rotate one turn with each other, and the rock drilling tools advance or retreat one pitch.
Manual operation of the receiving and unloading rod, because the advancing speed cannot be controlled, the threads of the rock drilling tools are affected by the rigid transmission force of the advancing oil cylinder and are easily damaged due to mutual extrusion. If only the rotary motion of the rotary head is used when receiving and unloading the thread of rock drilling tools, the forward or backward movement of rock drilling tools is in a state of free movement. The axial displacement can be automatically compensated according to the mutual engagement of the rock drilling tools thread so that the damage to the rock drilling tools threads can be avoided. The floating state of the rock drilling tools is realized mainly by connecting the rodless cavity and the rod cavity hydraulic oil of the propulsion cylinder.