Core Drill Reversing Speed Control for Borehole Extraction
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Solution Overview
Problem
Core drilling operations often result in drill bits becoming misaligned, bending, or getting damaged due to irregularities in the borehole, making it difficult to remove the drill bit after completion, especially when dealing with materials like concrete or brickwork.
Innovation Solution
A control method for the core drilling system that includes determining the end of the drilling operation based on predetermined parameters and switching to a reversing mode with a rotational speed multiple of the initial tapping speed to safely retrieve the drill bit, reducing the risk of damage from unevenness or obstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drill bit is removed from the borehole at normal rotational speed after drilling operation, then the drilling operation can be completed efficiently, but the drill bit and core drill are susceptible to damage from unevenness, irregularities, or obstructions in the borehole
Solution Approach 1:
The system dynamically adjusts the rotational speed of the drilling tool based on the operational phase. During the extraction phase, the rotational speed is increased to a multiple of the initial tapping speed, transforming the static removal process into a dynamic one that actively navigates through borehole irregularities, thereby improving reliability without permanently sacrificing drilling efficiency
Solution Approach 2:
The patent changes the rotational speed parameter from the initial tapping speed during drilling to a multiple of that speed during extraction. This parameter change enables the drilling tool to better handle obstructions and irregularities during removal, enhancing robustness while maintaining efficient drilling operations
2Adaptability or versatility
If the drill bit runs on the surface of the material or bends during core drilling operation, then the drilling can adapt to material variations, but the drill bit becomes misaligned or damaged making removal difficult
Solution Approach 1:
Instead of attempting to carefully and slowly extract the drill bit at low speed, the patent inverts the approach by rotating the drill bit at a higher speed (multiple of initial tapping speed) during extraction. This reversed strategy uses the increased rotational momentum to push through misalignments and obstructions, making removal easier despite earlier adaptations to material variations
3Reliability
If individual pieces of rock or parts of rebar are located in the borehole, then the borehole contains obstructions, but the drill bit may be damaged during attempt to remove it at normal speed
Solution Approach 1:
The patent applies the skipping principle by rapidly rotating the drill bit at a multiple of the initial tapping speed during extraction. This high-speed rotation allows the drill bit to quickly skip over or crush obstructions like rock pieces or rebar parts, reducing the time spent on removal while protecting against damage through the increased rotational force
Data Source
AI summary
A control method for the use of a core drilling system including a core drill and a feed device for driving the core drill along a machine holding device. The method includes the steps of determining the end of a core drilling operation on the basis of reaching a predetermined threshold value for at least one corresponding predefined drilling parameter; and of selecting a reversing mode for retracting a drilling tool out of a borehole at a reversing rotational speed which corresponds to a multiple of a predetermined tapping rotational speed of the drilling tool at the beginning of the core drilling operation.