Patent ID: 6029754
Filing Date: 2000-02-29
Classification: E21B

Abstract:
Drilling device having a drive motor (22) which sets a tool (36) in rotation, having a feed motor (14) which axially displaces the tool (36), and having a supply unit (64, 66) which supplies the drive motor (22) and the feed motor (14), there being associated with the drive motor a load sensor (20) which is connected to a feed control unit (42) for the feed motor (14), wherein:a) disposed between supply unit (64, 66) and drive motor (22) is a current controller (46), by means of which the speed of the drive motor (22) may be influenced,b) in addition to the load sensor (20) further sensors (12, 18, 24) are disposed which, besides the tool feedrate (V), determine at least two variables from the following group: tool feed force (F), tool torque (M) and tool speed (U),c) an evaluation and control unit (70) receives the output signals of the sensors (12, 18, 20, 24) and activates the feed control unit (42) and the current controller (46) in such a way thatca) the sum of the products of tool speed (U) and tool torque (M), and of feedrate (V) and feed force (F), substantially corresponds to the maximum total output power of the supply unit (64, 66),cb) the tool speed (U) or the tool torque (M) and the tool feed force (F), given any ground hardness (H), are tuned to one another in such a way that the feedrate (V) is maximized.