Drill Bit Shank Attachment Using Offset Concentric Surfaces
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Solution Overview
Problem
Conventional methods face difficulties in attaching a metal shank to bit bodies made from hard and abrasive particle-matrix composite materials, especially when new composite materials with higher melting points or chemical incompatibility are used, making it challenging to secure drill bits to drill strings effectively.
Innovation Solution
The solution involves directly attaching a shank to a bit body formed from particle-matrix composite materials using abutting surfaces that are concentric to an offset or shifted axis, with optional braze alloy or mechanical fastening, eliminating the need for a metal blank and allowing for secure attachment without conventional threaded connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional threaded connections and welds are used to attach a shank to a bit body made from particle-matrix composite material, then the drill bit can be secured to the drill string, but the attachment is prone to rotational slippage and failure especially at increased well bore depths
Solution Approach 1:
The patent removes the metal blank component from the attachment structure, directly attaching the shank to the bit body made from particle-matrix composite material. This eliminates the intermediate connection element that was prone to failure, simplifying the structure while improving reliability through direct attachment.
Solution Approach 2:
The abutting surfaces are configured with concentric offset axes during manufacturing to pre-establish rotational resistance geometry. This preliminary geometric configuration ensures that when the shank is attached to the bit body, the offset concentricity automatically provides rotational slippage prevention without requiring additional fastening mechanisms.
2Device complexity
If a metal blank is used as an intermediate component to attach the shank to the bit body, then the attachment structure is simpler, but the metal blank creates additional failure points and rotational slippage risks
Solution Approach 1:
The patent eliminates the metal blank from the attachment assembly, creating a direct bond between the shank and the particle-matrix composite bit body. This removal of the intermediate component reduces the number of potential failure points while simplifying the overall connection structure.
Solution Approach 2:
The shank attachment is merged directly with the bit body structure through configured abutting surfaces. By eliminating the metal blank intermediary, the shank becomes integrally connected to the bit body, creating a unified attachment system that reduces complexity and improves reliability simultaneously.
3Reliability
If new composite materials with higher melting points or chemical incompatibility are used for the bit body, then the bit body performance and durability are improved, but conventional attachment methods become ineffective
Solution Approach 1:
The patent replaces thermal attachment methods (welding, brazing) with a mechanical attachment system using configured abutting surfaces with concentric offset axes. This mechanical approach avoids the need for thermal or chemical compatibility between the shank and the particle-matrix composite material, enabling effective attachment of new composite materials that would be incompatible with conventional thermal attachment methods.
Solution Approach 2:
The concentric offset axis configuration acts as a geometric intermediary that enables attachment without requiring material compatibility. The offset concentric geometry provides a mechanical interface that transfers loads effectively between the shank and the chemically incompatible or high melting point composite material, bypassing the need for thermal or chemical bonding.
4Ease of manufacture
If conventional attachment methods are used, then the manufacturing process is well-established, but the attachment fails under increased well bore depth conditions
Solution Approach 1:
The abutting surfaces are configured with concentric offset axes during the manufacturing process, pre-establishing the geometric features needed for rotational resistance. This preliminary configuration integrates the attachment geometry into the manufacturing process itself, maintaining ease of manufacture while ensuring the attachment can withstand increased well bore depth conditions.
Solution Approach 2:
The patent changes the geometric parameters of the attachment interface by configuring abutting surfaces with concentric offset axes instead of conventional concentric or flat interfaces. This parameter change in the geometric configuration enables the attachment to resist rotational forces under increased well bore depth conditions while maintaining compatibility with established manufacturing processes for creating the offset concentric geometry.
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
This method enhances the durability and performance of drill bits by providing a secure attachment that prevents rotational slippage and failure, even at increased well bore depths, reducing the need for frequent drill bit changes and improving drilling efficiency.
Implementation Method 1
with optional braze alloy or mechanical fastening
Data Source
AI summary
Earth-boring rotary drill bits including a bit body attached to a shank. In some embodiments, the bit body and the shank may have abutting surfaces concentric to an interface axis offset relative to a longitudinal axis of the drill bit. In additional embodiments, the bit body and the shank may have generally frustoconical abutting surfaces. Methods for attaching a shank and a bit body of an earth-boring rotary drill bit include abutting a surface of a shank against a surface of a bit body, and causing the abutting surfaces to be concentric to an axis that is offset or shifted relative to a longitudinal axis of the drill bit.