Anti-Rotation Keyed Threaded Connector Without Axial Compression
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Solution Overview
Problem
Current anti-rotation key designs for large diameter pipes in offshore hydrocarbon drilling and production operations often require specialty tools, generate excessive axial compressive loads, and can permanently deform connector members, leading to inadequate locking and potential metal shavings issues during drilling.
Innovation Solution
An anti-rotation key system that minimizes axial compressive load by using a pin key with teeth that mate with box teeth, preventing rotation without radial or axial compression, and allowing for easy disassembly by using a wedge fastener to secure the pin key within a recess, thus maintaining the load path through the threaded connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional anti-rotation keys with teeth are used to prevent loosening, then the locking capability is improved, but excessive axial compressive load is generated and connector members are permanently deformed
Solution Approach 1:
Instead of having the key teeth bite into the connector members to create locking (conventional approach), the invention inverts the mechanism by having the box teeth engage the pin key teeth without the key applying compressive load to the connectors. The locking is achieved through the interlocking teeth geometry rather than through compression, thus preventing loosening while preserving connector member integrity.
Solution Approach 2:
The invention extracts the harmful axial compressive load function from the anti-rotation key mechanism. By designing the pin key to engage box teeth in a manner that prevents rotation without transmitting compressive loads to the pin or box, the solution removes the detrimental effect while retaining the beneficial anti-rotation function.
2Reliability
If drilling a hole for the locking member is performed after pipe connection, then the anti-rotation function is achieved, but metal shavings fall down the pipe string and cause issues
Solution Approach 1:
The pin key is designed to be inserted into the pin recess before the pin is threaded into the box. This preliminary positioning allows the key to be in place before connection, eliminating the need to drill through the made-up joint and preventing metal shavings from contaminating the pipe string interior.
Solution Approach 2:
The pin recess acts as an intermediary space that allows the pin key to be positioned and secured without requiring penetration through the finished threaded connection. This intermediate structure enables anti-rotation key installation while avoiding the harmful drilling operation through the pipe string.
3Reliability
If specialty tools or explosive powered guns are used to install the locking mechanism, then the anti-rotation function is achieved, but the device complexity and operational difficulty increase
Solution Approach 1:
The pin key is designed to be manually inserted into the pin recess and secured with a simple fastener that can be tightened with basic tools. The anti-rotation function is achieved through the self-contained tooth engagement mechanism between the pin key and box teeth, eliminating the need for specialty installation tools or explosive powered guns.
Solution Approach 2:
The anti-rotation mechanism is segmented into independent components: the pin key with teeth, the pin recess, and simple fasteners. This segmentation allows each component to be installed and secured independently using basic tools, rather than requiring complex integrated installation systems.
4Reliability
If anti-rotation key teeth bite into connector members upon insertion or rotation, then the locking capability is improved, but axial compressive load is applied and connector members are permanently deformed
Solution Approach 1:
The invention inverts the traditional engagement mechanism by having the box teeth (on the box) engage the pin key teeth (on the pin key) rather than the key teeth biting into the connector members. This reversal ensures that the engagement forces are transmitted through the tooth interfaces without applying compressive loads to the pin or box structures, preventing permanent deformation while maintaining locking capability.
Data Source
Figure 1
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Figure 4
AI summary
A tubular member connection system (11) includes a pin (15), external pin threads (17), and an annular pin lip (21) at a shoulder surface (20) of the pin. A box (27) has internal box threads (29) and an annular box lip (31) at an end surface of the box. The box threads are shaped to mate with the pin threads to releasably secure the pin to the box. A pin recess (22) is formed in an outer diameter surface of the pin, the pin recess extending in an axial direction from the pin lip. A pin key (59) is selectively fastenable within the pin recess, the pin key having pin teeth (69) on an outer edge of the pin key. The box teeth (33) are located in the box. The box teeth (33) selectively mate with the pin teeth (69) and resist rotation of the pin relative to the box.