Drill String Thread Jamming Prevention
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Solution Overview
Problem
Existing thread designs, particularly in high torque, high power, and high speed applications, are prone to jamming and cross-threading due to their inherent wedging mechanisms, which can lead to significant damage and reduced fluid-tight seals in drilling operations.
Innovation Solution
The development of drill string components with threads featuring a leading end oriented at an acute angle relative to the central axis, providing an abrupt transition to full thread depth and width, which reduces the likelihood of jamming and cross-threading by eliminating tail-type thread starts and promoting a sliding interface during mating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional tail-type thread starts are used, then threading can be standardized and manufactured easily, but jamming and cross-threading occur due to wedging mechanisms in high torque applications
Solution Approach 1:
The patent extracts and removes the problematic tail-type thread start geometry from the thread design. By eliminating the gradual taper transition that causes wedging, the invention prevents the jamming mechanism while maintaining standard thread forms for the majority of the thread length, thus preserving ease of manufacture while improving reliability
Solution Approach 2:
Instead of using a traditional gradual taper from small to large diameter (tail-type start), the invention inverts the approach by providing an abrupt transition to full thread depth and width. This reversal of the transition geometry eliminates the wedging action that causes jamming in high torque applications
2Adaptability or versatility
If tapered threads are used to accommodate size differences, then mating of different sized components is enabled, but jamming becomes more common due to the wedging mechanism
Solution Approach 1:
The patent converts the harmful wedging mechanism into a beneficial sliding interface. By designing the thread start to promote sliding rather than wedging, the invention eliminates jamming while maintaining the ability to accommodate size differences between mating components through controlled abrupt transitions
3Adaptability or versatility
If standard thread designs are used, then interchangeability between manufacturers is achieved, but innovation in thread design is diminished and jamming persists in high power applications
Solution Approach 1:
The patent applies local quality by modifying only the thread start geometry (the local region where jamming occurs) while maintaining standard thread forms for the remainder of the thread. This localized modification preserves interchangeability with standard threads while eliminating jamming through the abrupt transition design at the critical thread start location
Data Source
AI summary
A drill string components having a thread extending around a body. The leading end of the thread can have a configuration that resists jamming and cross-threading. In particular, the leading end of the thread can include 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. The leading end of the thread can be oriented at an angle relative to the axis of the drill string component. When mating male and female threads are similarly structured, the mating threads slide together along an interface at the thread start face and are drawn into a fully thread-coupled condition. The thread starts may have full circumference mating with no jamming positions.