Stepped Groove Collar Retaining Ring for Drill String Torque
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Solution Overview
Problem
Existing dual-member drill strings face challenges in efficiently connecting and disconnecting inner pipe members without threading, which complicates the make-up and break-up processes, and requires effective torque transmission while allowing for steering and drill bit rotation.
Innovation Solution
A tubular collar with a step-like internal groove and a retaining ring that expands and contracts to secure the collar onto the inner pipe member, forming a torque-transmitting connection that restricts axial movement, allowing for efficient assembly and disassembly without threading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If threading is used to connect inner pipe members, then torque transmission is reliable, but the make-up and break-up processes become complicated and time-consuming
Solution Approach 1:
The connection mechanism is segmented into modular components: a collar with an internal groove, a retaining ring with external grooves, and engagement features that divide the connection function into discrete elements. This segmentation allows for faster assembly by eliminating complex threading while maintaining connection integrity through the collaborative interaction of simplified components.
Solution Approach 2:
Instead of using traditional threading where the inner pipe member threads into the collar, the invention inverts the approach by using a retaining ring that engages with grooves on both the collar and pipe member. The retention feature is inverted from a threaded engagement to a groove-based mechanical interlock, enabling faster make-up and break-up operations.
2Productivity
If a simple groove connection is used, then assembly is fast, but torque transmission capability is insufficient
Solution Approach 1:
The invention merges multiple retention features into a single integrated retaining ring structure. The retaining ring combines external grooves for engagement with the collar, internal features for securing to the pipe member, and axial retention capabilities. This merging of functions into one component achieves both fast assembly and high torque transmission strength.
Solution Approach 2:
The retaining ring incorporates dynamic engagement features including ramps that allow the ring to seat and lock into position during assembly, and elastic or deformable elements that enable the ring to flex during installation while maintaining strong torque transmission when engaged. This dynamic behavior enables fast assembly followed by secure torque-carrying connection.
3Stability of the object's composition
If the retaining ring is held axially in the groove, then connection stability is improved, but the ring may not properly engage with the pipe member
Solution Approach 1:
The retaining ring features localized engagement zones with different geometries: external grooves for collar engagement, internal features for pipe member securing, and axial retention elements positioned at specific locations. Each local region of the ring is optimized for its specific function, ensuring both axial stability and proper engagement with the pipe member simultaneously.
Solution Approach 2:
The retaining ring acts as an intermediary component that mediates between the collar and the inner pipe member. It translates the axial positioning provided by the collar groove into secure engagement with the pipe member through its dual-groove design, ensuring both connection stability and engagement reliability through this mediating structure.
Data Source
AI summary
An assembly for a torque-transmitting connection in an inner pipe string of a dual-member drill string is formed from a collar, a retaining ring, and an inner pipe member. An endless internal groove having adjacent shallow and deep sections is formed in the collar. Formed in the inner pipe member, an endless external groove is situated in concentric relationship with the internal groove. The retaining ring, situated within the grooves, resists disconnection of the collar from the inner pipe member. When the assembly is subjected to an axial force that might otherwise tend to pull it apart, the retaining ring resists the tendency by wedging between the bottom of the shallow section of the internal groove and the crest of the external groove.