Sacrificial O-Ring Locking Pin for Drill String Coupling
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Solution Overview
Problem
Existing methods for coupling drill string components, such as threaded connections, hex collar systems, and round box and pin systems, face issues like loosening, difficulty in alignment, and high manufacturing costs, leading to safety concerns and inefficiencies in drilling operations.
Innovation Solution
A sacrificial o-ring locking pin system that securely couples components by using a locking pin with a groove and o-ring, allowing for easy assembly and disassembly, and withstanding high torques and lateral loads, while being cost-effective and simple to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If threaded connections are used to couple drill string components, then the connection can be made with simple structure, but the connection tends to vibrate loose and break, reducing reliability
Solution Approach 1:
The connection system is divided into separate functional elements: a male component with external features, a female component with internal features, and a distinct locking pin that secures the connection. This segmentation allows each element to perform its specific function optimally while improving overall reliability compared to integrated threaded connections.
Solution Approach 2:
The locking pin is pre-installed in the female component before coupling with the male component. This preliminary action ensures that the locking mechanism is already in place and ready to secure the connection, preventing loosening and breaking during drilling operations without requiring additional tightening steps.
2Reliability
If hex collar with bolts is used to secure threaded connections, then safety is improved, but the system becomes more complex and the threads cannot be tightened to full torque
Solution Approach 1:
The locking function is extracted from the threaded connection system and implemented as a separate locking pin mechanism. This removes the need for hex collars and multiple bolts, allowing the threads to be tightened to full torque while maintaining safety through the dedicated locking pin that prevents loosening.
Solution Approach 2:
The locking pin serves multiple functions: it secures the threaded connection against loosening, provides a positive mechanical lock, and prevents complete separation of components. This multi-functionality replaces the need for separate hex collars and bolts, simplifying the overall system while maintaining or improving safety.
3Strength
If roll pins or dowel pins are driven into holes to secure round box and pin connections, then connection strength is improved, but driving pins in and out becomes difficult in tight areas
Solution Approach 1:
The locking pin is pre-installed in the female component before coupling with the male component. This preliminary installation allows the pin to be easily positioned and secured without requiring difficult field operations in tight areas, while still providing the strength benefits of a mechanically locked connection.
4Reliability
If notch and projection systems with tight tolerances are used for alignment, then connection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The locking pin features an asymmetric square cross-section that engages with a corresponding asymmetric recess in the female component. This asymmetric design provides precise alignment and positioning without requiring tight tolerances on circular features, reducing manufacturing costs while maintaining connection reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides a secure, reliable, and cost-effective means of coupling drill string components, preventing loosening during drilling operations and reducing the need for multiple locking pins, while being safer and easier to disconnect than traditional methods.
Implementation Method 1
The o-ring has an inside diameter that is less than the diameter of the square edge and an outside diameter that is greater than the diameter of the square edge. The locking pin is inserted into the first and second openings. The first and second components are coupled together. The o-ring is located in the recess.
Data Source
AI summary
First and second components can be releasably coupled together with a locking pin having a sacrificial o-ring. The first and second components have respective first and second openings that are aligned with each other and receive the locking pin. The second opening has a square edge located adjacent to a recess in the first opening. The o-ring has an outside diameter greater than the diameter of the square edge and an inside diameter less than the diameter of the square edge when assembled. The locking pin is inside of the first and second openings, with the o-ring inside of the recess. To release the components, the locking pin is moved out of the first opening to shear the o-ring against the square edge.