Coupled Nut Retention Assembly for Vibration-Loosening Prevention
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Solution Overview
Problem
Threaded fasteners in systems subject to vibration often loosen, leading to undesirable damage, particularly in applications like aircraft wheels, where existing solutions do not effectively prevent loosening.
Innovation Solution
A nut retention arrangement featuring a first and second nut with retention apertures and a tensile member, such as a safety cable or wire, where rotation towards loosening of one nut causes tightening of the other, preventing loosening by coupling the nuts to threaded fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If threaded fasteners are used in vibrating systems, then the system can be assembled with simple fastening components, but the fasteners will loosen over time due to vibration
Solution Approach 1:
The patent combines multiple fastening functions into a single integrated system. The safety wire serves dual purposes: it acts as both a locking mechanism (preventing loosening) and a tensile member (providing additional clamping force). The safety wire is integrated through the fastener structure, merging the locking and tensile functions into one unified component system rather than separate elements.
Solution Approach 2:
The safety wire acts as an intermediary element between the two fasteners. It connects the fasteners mechanically and creates a coupled system where the state of one fastener influences the other. The wire mediates the interaction between fasteners, ensuring that loosening of one cannot occur independently without affecting the other through the wire's tensile constraint.
2Device complexity
If friction between nut and bolt is relied upon to prevent loosening, then the design remains simple, but friction may be insufficient under high vibration conditions
Solution Approach 1:
The safety wire applies a preliminary counteracting force that opposes the loosening tendency before vibration can cause significant loosening. The wire is pre-tensioned to create an initial clamping force that actively resists the loosening moment, rather than relying solely on friction to react after loosening begins. This preliminary anti-action prevents the loosening process from initiating under vibrational loads.
Solution Approach 2:
The fasteners are pre-assembled with the safety wire installed and tensioned before the system operates under vibration. This preliminary action ensures that the anti-loosening mechanism is already in place and engaged, providing immediate protection against vibration-induced loosening rather than requiring additional components or complex assembly procedures.
3Device complexity
If a single nut is used to secure a threaded fastener, then the assembly is simple, but the nut can still rotate loose under vibration
Solution Approach 1:
The patent creates an asymmetric constraint system where the two nuts are not independently secured but are coupled through the safety wire. This asymmetric arrangement means that the security of each nut depends on the state of the other, creating a相互 dependent (mutually dependent) security system rather than two independent single-nut arrangements. The wire creates an asymmetric tensile relationship that prevents symmetric loosening of both nuts.
Solution Approach 2:
The fastening system is segmented into two separate nut-fastener assemblies that are then coupled through the safety wire. This segmentation allows each nut to be independently installed and tensioned, yet the wire creates a functional connection that provides collective security. The segmentation enables modular assembly while achieving enhanced reliability through the coupling mechanism.
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
Effectively prevents threaded fasteners from loosening by ensuring that rotation in one direction tightens the other nut, thereby maintaining system integrity and preventing damage from loose fasteners.
Implementation Method 1
Friction between the nut and bolt may aid in preventing the nut from rotating loose from the bolt
Data Source
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AI summary
A nut retention arrangement may comprise a first nut (425) comprising a first threaded aperture (626) and a first retention aperture (600a), a second nut (435) comprising a second threaded aperture and a second retention aperture, and a tensile member (410) having a first end extending through the first retention aperture and a second end extending through the second retention aperture such that rotation in a direction toward loosening of either the first nut or the second nut causes rotation in a direction toward tightening of the other of the first nut or the second nut.