Method and a device for drilling with several tools in simultaneous operation
AssigneeMaschinen- und Bohrgerate-Fabrik Alfred Wirth & Co., K.G.
InventorsWilfried Sackmann, Georg Hurtz, Fritz Tibussek
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Abstract
A method for drilling boreholes utilizing a plurality of simultaneously operated boring tools. During a drilling operation the loading forces on the tools are measured and constantly compared with a predetermined limiting value representative of a limiting loading value and the variation of a limiting loading value with respect to time. If these limiting values are exceeded at least one working parameter of the tools is adjusted such as feed force, feed speed or track speed of the tools. Apparatus for carrying out the method is also disclosed.
Claims54
A method of drilling a borehole with a plurality of tools in simultaneous operation, the tools being mounted on a rotatable drill head adapted to be rotated by rotary-motion drive means and to be moved in the direction of the borehole by forward-feed drive means, the tools moving in circular tracks (paths) during rotation of the drill head and executing jointly the boring work, the parameters of the boring procedure being:a) the track speed of the tools (being proportional to rotational speed of the drill head), b) the forward driving force applied to the drill head and the tools thereon and c) the forward-feed speed of the drill head and the tools thereon, the method comprising the steps of:
- measuring at least at one of the working tools on the drill head a load characterizing value representative of the stress of said tool itself;
- comparing these measured load values with a predetermined limiting value;
- and altering at least one of said working parameters if this limiting value is exceeded.
A device for drilling a borehole comprising a drill head having mounted thereon a plurality of tools, rotary motion drive means and forward-feed drive means for rotating and feeding the drill head respectively, tool load measuring means located at and operatively associated with at least one of the tools on said drill head and including means to supply measured individual tool load value signals, computer means coupled to said tool load value signals to output signals representative of the stress acting individually on at least one of the tools on said drill head, and operational means adapted to receive said output signals and comprising comparator means for determining and passing on those of the output signals of the computer means supplied to it that exceed a preset limited value, regulator means coupled to said comparator means for receiving the signals exceeding said limiting value, and servo members for controlling said drivemeans for the drill head and being operatively associated to said regulator means.
Dependencies are inferred from the claim text.