Dual Pipe Drilling Head Non-Circular Torque Transmission
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Solution Overview
Problem
Existing horizontal directional drilling systems face challenges in efficiently transmitting torque to cutting tools without the need for threaded connections, which can be cumbersome and limit fluid flow rates to the drilling site.
Innovation Solution
A downhole tool assembly with a chuck, hub, and elongate drive member featuring non-circular surfaces for connector-free torque-transmitting engagement, allowing independent rotation of the cutting tool and housing, while maintaining high fluid flow rates through a 'floating spindle' design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If threaded connections are used to transmit torque, then torque transmission is achieved, but device complexity increases and fluid flow rate decreases
Solution Approach 1:
The patent removes the threaded connector from the system entirely. The drive member features a non-circular cross-section that directly engages with the chuck's non-circular interior surface, eliminating the need for separate threaded connections while maintaining torque transmission capability.
Solution Approach 2:
The drive member and chuck utilize non-circular (asymmetric) cross-sections instead of traditional circular threaded connections. This asymmetric geometry provides both torque transmission and positional orientation without requiring threaded fasteners, thereby reducing device complexity.
2Ease of operation
If threaded connections are used to transmit torque, then torque transmission is achieved, but fluid flow rate to drilling site decreases
Solution Approach 1:
By removing the threaded connector assembly, the patent opens up the fluid passage completely. The direct non-circular engagement between drive member and chuck eliminates obstructions to fluid flow while maintaining the necessary torque transmission function.
3Device complexity
If connector-free torque transmission is implemented, then device complexity decreases and fluid flow rate increases, but torque transmission reliability may be compromised
Solution Approach 1:
The non-circular cross-sections of the drive member and chuck create a mechanically interlocking engagement that reliably transmits torque. The asymmetric geometry prevents relative rotation and slippage, ensuring stable torque transmission without requiring threaded fasteners.
Solution Approach 2:
The patent employs curved, non-circular surfaces that provide continuous contact between the drive member and chuck. This curved engagement surface distributes stress and maintains reliable torque transmission throughout the drilling operation.
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
Enables efficient directional drilling by providing a robust, connector-free torque transmission system that enhances drilling efficiency and fluid flow, suitable for diverse soil conditions, including soft soil and rocks.
Implementation Method 1
The pin end of the drive member is slidably receivable in connector-free torque-transmitting engagement with the non-circular interior surface of the chuck
Implementation Method 2
The drive member has a geometrically-shaped pin end. The pin end of the drive member is slidably receivable in connector-free torque-transmitting engagement with the geometrically-shaped interior surface of the chuck
Data Source
AI summary
A downhole tool assembly for use in directional drilling operations. The assembly has a housing, a chuck, a cutting tool, a hub, and an elongate drive member. The housing has a spindle for supporting the hub and chuck for rotation thereon. The chuck is connected to the hub and has a non-circular interior surface and a box for supporting a cutting tool for rotation with the chuck. The elongate drive member is disposed within the housing, the hub, and the chuck. The drive member is operatively connected to the inner member of a dual-member drill string for rotation independently of the housing. The drive member has a non-circular external surface corresponding to the non-circular interior surface of the chuck. The pin end of the drive is slidably receivable in connector free torque-transmitting engagement with the interior surface of the chuck to drive rotation of the cutting tool, chuck, and hub independently of the housing.