Unbalance bore
The unbalance bore was developed in 1834 by mining pioneer Josef Karlinger. It is used to guide the drill through stony to loamy sediment in order to be able to collect and analyze samples of the soil resources even in deeper layers of the earth.
history
Karlinger designed the hollow-jacketed unbalance drill for this purpose. The drill head of this device consists of three interlocking, slightly elliptical milling cutters that are operated by a chain. The chain is mounted on a drive string within the inner drill pipe. If the inner linkage is motivated, the milling machines begin to rotate with an imbalance in the range of a tenth of a millimeter. In order to stabilize the downward movement of the drill in the countersunk hole, water is pumped through the outer drill pipe without excessive pressure.
This process was first used by Karlinger in 1835 for coal mining in Sulzgraben near Parsberg .
present
In the course of time, the original unbalanced bore was hardly modified because of its extreme efficiency. Only the drive of the drill rod was gradually converted from human and animal muscle power to steam power and finally replaced by the combustion engine. Even after more than 170 years, this type of exploration is still the first choice for determining rock layers in mining .