Drill Rod Thread Engagement via Rotational Slip Detection
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Solution Overview
Problem
Existing Rod Handling Systems face challenges in automatically and safely connecting drill rods due to low thread height and conical threads, resulting in a high failure rate of thread engagement, which leads to increased costs and manual labor.
Innovation Solution
A method involving axial alignment, rotational positioning, and axial biasing of drill rods to identify the correct thread entrance, using a system with rotatable gripping members and sensors to detect the rotational position where threads slip over each other, ensuring proper engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automatic rod connection is implemented, then productivity is improved, but reliability deteriorates due to high thread engagement failure rate
Solution Approach 1:
The system performs preliminary rotational alignment of the drill rod threads before final engagement. The rod is rotated to a predetermined angular position that pre-aligns the thread entrances, ensuring that when axial engagement occurs, the threads are already positioned for successful engagement rather than random alignment.
Solution Approach 2:
The system incorporates sensors that detect the rotational position of the drill rod and provide feedback to the control system. This feedback mechanism allows the system to monitor thread alignment status and adjust the rotational position accordingly, ensuring proper thread engagement before final connection.
2Reliability
If thread detection and alignment mechanisms are added, then thread engagement reliability is improved, but device complexity increases
Solution Approach 1:
The system uses an intermediary rotational alignment mechanism that mediates between the random rotational position of incoming rods and the required precise thread alignment. This intermediary step of controlled rotation acts as a buffer that simplifies the overall engagement process by decoupling axial feeding from rotational alignment.
Solution Approach 2:
The system utilizes the existing rotational degrees of freedom of the drill rod handling mechanism to perform self-alignment. Rather than adding completely independent alignment apparatus, the system leverages the natural rotational capability of the rod feeding mechanism to achieve proper thread orientation through controlled rotation.
Data Source
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AI summary
A method of interconnecting a drill rod (11') with a drill string (11) by means of a threaded connection (112, 111') is disclosed. The method comprises axially aligning the drill rod (11') with the drill string (11), rotating the drill rod (11') in a disengagement rotational direction of the threaded connection (112, 111'), identifying a rotational position of the drill rod (11') where thread ends of the rod and the drill string (11) slip over each other, stopping said rotating within a predetermined period of identifying the rotational position, and rotating the drill rod (11') in an engagement direction, such that the drill rod (11') is interconnected with the drill string (11) by the threaded connection (112, 111').