New all-hydraulic crawler drills

Press, 17 September 1987, Page 53

New all-hydraulic crawler drills

Atlas Copco is introducing yet another series of crawler drill: An all-hy-draulic series with versions for production drilling (in small surface mines and quarries) and for civil engineering applications. They are small, lightweight, one-man-operated, but capable of high power outputs, and, therefore, of outstanding net penetration rates and high annual production capacities. Their hydraulic rock drills have three different impact stroke settings which enable them to be easily adapted to differing rock conditions and varying types of drill steel.

The tramming controls are mounted on the rear platform together with one set of controls for positioning the feed. Positioning can also be carried out from a front panel mounted on the feed. The drilling controls are also located on this front panel. A wide range of standard options are available from the factory, for example, dust collectors, flushing-air sensors, anti-freeze dosimeters, feed rod racks, inclination instruments — in order to make each rig

tailor-made for its particular purpose. The power-pack consists of a turbo-charged, four-cylinder Deutz diesel engine, 8F4L913, which can deliver a maximum power output of 69 kW at 2300 r.p.m. The rigs are equipped with four hydraulic pumps. The main pump, which provides the power for the drill’s impact mechanism, is flow and pressure regulated to optimise energy utilisation. The other pumps, which provide power for service functions, all operate individually. This makes them easily adjustable to differing rock conditions and to use with different drills and rock tools.

The hydraulic system has built-in automatic functions which maximise drilling capacity and avoid damage to the drill steel. Impact energy can easily be reduced at the beginning of drilling operations, in order to ensure safe collaring, and also in situations where the bit meets no resistance.

This can occur, for example, where the bit breaks through into rock fissures. The problem

here is that the full impact energy from highly effective, hydraulic rock drills, (such as those mounted on these rigs) — when not absorbed by the resistance of the rock — can cause damage to drill steels.

Another automatic system prevents jamming: This monitors torque resistance. When excessive torque is indicated, i.e. when jamming is likely to occur, the system automatically stops exerting feed pressure on the bit and reduces the impact energy. Drilling proceeds very gently until the bit can rotate normally again. Regular drilling is then recommenced. (The same procedure is automatically followed if the bit’s flushing holes become blocked.) These automated systems increase penetration rates and reduce the need for replacement parts. The single boom, R.O.C. 512 H.C.-00 version is equipped with the COP 1238 LP hydraulic rock drill. This drill delivers an impact power of 11 kW. Used in conjunction with R 32 or T 38 extension rods, it covers the 48 to 76 mm hole diameter range.