Development And Experimental Study Of The Pneumatic Universal Drill

Drilling holes in all directions in the tunnel are widely required in railway tunneling, urban subway tunneling and coalmine roadway excavations. The common disasters in coalmines are gas/water gushingness in the tunnel and collapse of the tunnel wall or roof. A simple way to avoid gas/water gushingness is to drill a deep hole in the direction of the tunnelling before the tunnel is excavated. And high quality cable bolts in all directions of the tunnel will guarantee the stability and safety. Unfortunately, however, to accomplish these work need many types of drilling equipment with different power in the narrow work face of the tunnel at present, and that much depressed the work efficiency, and brought some potential risk as well. Some coalmines ignored the drilling ahead before excavation, and hence caused many mine disasters recent years.This thesis developed a universal drill powered by compressed air, its drilling position and direction can be adjusted easily. The universal drill can be divided into two parts, they are drill rig and a drill thrust by cylinder. The drill rig stands on the floor of the tunnel, and a multi-stage air cylinder on the top of the rig and supports the roof of the tunnel to make the rig stable. The poles of the rig work as a track of the drill, and the elevation mechanism, angle adjust mechanism and drill clasp mechanism are installed on the track and can slide on it. The height of the drill is controlled by a pulley block and a winch. The double acting multi-stage pneumatic cylinder of the drill clamped in the clasp mechanism. The drill is powered by pneumatic motor and pneumatic cylinder in drilling.The strength and stability of the drill rig was guaranteed by careful mechanics analysis. The block problem of the double-acting cylinder when retracting was improved through mechanics analysis; and the precision of the drill positioning was improved by theoretical analysis of the fix holes arrangements.Both laboratory tests and field trial were carried out after the universal drill developed. The laboratory tests show that the thrust and torque of the drill is much higher than existing rib drills, and the universal drill is easy in positioning and direction adjustment. The field trial in a roadway of a coal mine show that the universal drill is easy operated, quick drill, powerful. It could replace both roof bolters and rib drills, and it also can be used for gas/water exploration drilling. The universal drill supplies a new guarantee of safety for the coal mine production.