Dual-Thread Locking Fastener for Vibration-Resistant Reuse
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Solution Overview
Problem
Existing threaded fasteners loosen over time due to vibration and lack adequate anti-tampering features, with existing locking systems incurring permanent damage and requiring reapplication of thread locking compounds.
Innovation Solution
A fastener system comprising a first and second fastener component with opposite thread handedness, connected by a rotating joint that allows simultaneous counter-rotation to prevent axial movement and ensure secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard threaded fasteners are used, then the fastener can be easily installed and removed, but the fastener loosens over time due to vibration
Solution Approach 1:
The fastener is divided into two separate components: an inner threaded fastener and an outer threaded fastener. Each component can independently engage with its corresponding thread, allowing them to be tightened and loosened separately. This segmentation enables the locking mechanism to maintain reliability through differential rotation while preserving ease of operation by allowing controlled disassembly without damaging either thread.
Solution Approach 2:
The rotating joint introduces dynamic behavior to the fastening system. When torque is applied during tightening, the inner and outer fasteners can rotate different amounts relative to each other, allowing the joint to adapt and distribute stresses dynamically. This dynamic capability enables the system to accommodate thermal expansion, vibration, and assembly variations while maintaining secure engagement.
2Reliability
If thread locking compound is applied to standard fasteners, then locking effectiveness is improved, but the compound is messy and must be reapplied each time the fastener is removed
Solution Approach 1:
The rotating joint mechanism provides self-contained locking functionality through its mechanical design. The differential thread engagement and rotating joint geometry create inherent resistance to loosening without requiring external locking compounds. This self-service approach eliminates the need for messy chemicals and their periodic reapplication, as the mechanical locking feature remains effective throughout the fastener's service life.
3Reliability
If existing locking systems are used, then anti-tampering features are provided, but permanent damage occurs in the tightening and loosening process
Solution Approach 1:
By separating the fastening function into two independent threaded components, the system allows controlled disassembly where each component can be independently managed. The rotating joint acts as a reversible locking mechanism that can be repeatedly engaged and disengaged without causing permanent deformation or damage to either thread, enabling multiple reuse cycles while maintaining anti-tampering security features.
4Reliability
If a rotating joint is introduced to prevent axial movement, then locking reliability is improved, but device complexity increases
Solution Approach 1:
The rotating joint is integrated directly into the connection between the inner and outer threaded fasteners, merging the locking function with the fastening structure itself. Rather than adding a separate locking mechanism, the rotating joint is formed as part of the fastener assembly, where the differential thread engagement inherently provides axial movement prevention while maintaining a relatively simple overall structure.
Data Source
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AI summary
The present specification discloses a locking fastener that includes a first threaded fastener (22) axially positioned within an axial through hole (44) of a second threaded fastener, and captured therein by a rotating joint (26) that permits rotation of the first threaded fastener and the second threaded fastener relative to one another about a common thread axis. In one or more embodiments the first threaded fastener thread (34) handedness is opposite to the second threaded fastener thread (42) handedness. Additionally disclosed, is a screwdriver tool configured to simultaneously engage and oppositely rotate the first threaded fastener and the second threaded fastener into a mating component having a first mating thread and a second mating thread configured to receive the first threaded fastener and the second threaded fastener, respectively, driven at the same axial advance distance for each turn. Once tightened, the present locking fastener resists loosening and provides a tamper-resistant hold.