Drilling-joining machine

The scheme of the drilling-joining machine
1. the strut;
2. the chuck;
3. the hermetic seal;
4. the leading drill bit;
5. the widener of the hole;
6. the reference lantern;
7. the drilling rod with the screw conveyor;
8. the catcher.

DRILLING-JOINING MACHINE (EN: hole drilling machine; DE: Aufbruch-bohrmaschine; FR: perforatrice à grands trous; ES: perforadora; RU: буросбоечная машина) is purposed for the drilling of the vertical and inclined boreholes with the large diameter (150-1500 millimetres) and lengths of up to 150 metres during the joining of the underground mine workings. It is used in case of the underground development of the steep and slightly inclined coal layers, for the cutting of the longwall stopes, for the ventilation, and degassing of the layers, and so on.

They distinguish the drilling-joining machines: according to the purpose, namely, for the usage within the soft rocks and coals, within the medium and strong rocks; according to the type of the advancing mechanism, namely, with the mechanical (differential-screw), pneumatic, and hydraulic devices; according to the type of the working tool, namely, with the cutters, and with the roller-cones. There are most distributed within the USSR the drilling-joining machines with the differential-screw mechanism for the advancement (see the Figure), which is powered by the pneumatic or electric motor. The mechanism for the advancement terminates with the floating chuck, which moves along the guides, which are regulating its movement.

The drilling tool comprises the leading drilling bit, wideners, reference lanterns, and drilling rods. The leading drilling bit in the shape of the helix with the diameter of 10 millimetres drills the leading borehole, which helps to maintain the direction, and facilitates the destruction of the rock at the leading end of the borehole. For the prevention of the bending of the drilling string, they install within it (at the intervals of 6-8 drilling rods) the rod with the reference lantern. The drilling rods for the drilling with the angle of inclination of up to 45 degrees are constructed with the screw conveyors, which are removing the small particles from the drilling. For the catching and moving of the small particles onto the conveyor (or into the minecart), there is installed the hermetic seal. The performance of the drilling-joining machines during the drilling of the leading borehole is 50-60 metres per shift, while the performance during the widening of the borehole is 25-30 metres per shift. The further perfecting of the drilling-joining machines is associated with the decrease of their sizes, and with the creation of the self-propelled machines, which are situated within the borehole during the drilling.