Drill String Thread Joints with Asymmetric Progressive Fit
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Solution Overview
Problem
Existing drill component designs are prone to jamming, cross-threading, and wear due to inadequate material utilization and unsymmetrical load distribution, leading to reduced load capacity and reliability in high-torque and high-speed drilling applications.
Innovation Solution
The design incorporates drill string components with threads having leading ends oriented at an acute angle relative to the central axis, providing an abrupt transition to full thread depth and width, and featuring variable pitch and width, along with a cylindrical thread root and frusta-conical thread crest, which eliminates interference fits on thread features and optimizes material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional threaded connections are used in drill string components, then standardization and interchangeability are achieved, but the components are prone to jamming, cross-threading, and wear due to unsymmetrical load distribution and inadequate material utilization
Solution Approach 1:
The patent applies asymmetry by orienting thread leading ends at an acute angle relative to the central axis of the drill string component. This asymmetric thread configuration creates a progressive fit that guides mating threads into proper alignment, preventing cross-threading and jamming while maintaining standardization for interchangeability
2Ease of manufacture
If traditional thread designs with constant pitch and width are used, then manufacturing simplicity is maintained, but material utilization is inadequate leading to reduced load capacity
Solution Approach 1:
The patent applies local quality by implementing variable pitch and variable width along the thread length. The pitch and width are optimized at different locations: tighter pitch and appropriate width at the leading end for progressive engagement, and adjusted parameters along the thread body for optimal load distribution and material utilization, thereby increasing load capacity while remaining manufacturable
3Adaptability or versatility
If threads with parallel crests and standard geometry are used, then compatibility with existing standards is maintained, but jamming occurs due to inadequate clearance and unsymmetrical load response
Solution Approach 1:
The patent modifies standard thread geometry by orienting leading ends at an acute angle and implementing variable pitch and width. This creates an asymmetric progressive fit that provides built-in clearance and symmetrical load response during the threading operation, preventing jamming while maintaining compatibility with standard drill string component dimensions and external specifications
Data Source
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AI summary
Implementations of the present invention comprise drill string components having at least one thread extending around a body. The leading end of the thread can have a configuration having increased strength and resistance to jamming and cross-threading. In particular, the leading end of the thread can comprise a planar surface normal to the body. The leading end of the thread can provide an abrupt transition to full thread depth that helps reduce or eliminate cross-threading and can be oriented at an angle relative to the axis of the drill string component. The thread can further provide at least one of a variable thread width and a variable thread pitch configured to create an axial progressive fit. The thread can also provide a cylindrical thread root and a thread crest that circumscribes a frusta-cone over at least a portion of the axial length of the threads configured to create a radial progressive fit.