Sätt och anordning för precisionsborrning

摘要

A method for determining the position of a drill bit (14) at the end of a drill cable (11) during drilling or boring in rock or loose material (12), comprises the detection of an insert in the cable and measuring the degree of curvature of the measuring probe (15) inside this insert.The measuring probe contains several cables which are tensioned over two supports. The cables are not supported between the two supports and each cable has its own unique oscillation frequency for a given tension value when the measuring probe is in the starting position. The oscillation frequencies for the cables are measured when the drill bit is moved and from this data the degree and direction of curvature for the probe can be calculated in order to provide a current position in a coordinate system for the drill bit. The apparatus used in this method is also claimed, including a measuring probe that contains several cables arranged in a radial manner around its central axis and also contains devices for making the cables oscillate and detecting the oscillation frequencies. A signal analysis device (17) processes data from the devices in the probe in order to calculate the position of the drill bit.