Deformable Fastening Thread Wedge-Effect Loosening Resistance
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Solution Overview
Problem
Existing fastening mechanisms, such as bolts and nuts, tend to loosen over time due to manufacturing tolerances, and previous solutions that rely on elastic deformation to increase friction are limited in effectively resisting loosening forces, as they can counteract the tightening axial forces required to secure materials.
Innovation Solution
A fastener with a helical thread featuring a groove that allows for plastic deformation when subjected to axial force, increasing the major diameter of the thread and providing enhanced loosening resistance through a wedge effect, thereby maintaining the tightened state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic deformation is used to increase friction between thread flanks, then loosening resistance is improved, but tightening axial force is reduced because elastic deformation creates a loosening axial force opposing the tightening direction
Solution Approach 1:
The patent changes the deformation parameter from elastic to plastic. The groove in the thread root allows the thread material to undergo plastic deformation when tightened, permanently increasing the major diameter and creating a wedge effect that provides loosening resistance without generating opposing loosening axial forces during tightening
Solution Approach 2:
The patent segments the thread structure by introducing a groove at the thread root. This groove creates a stress concentration zone that facilitates localized plastic deformation, allowing the thread to expand and create the wedge effect while maintaining structural integrity elsewhere
2Ease of manufacture
If thread profiles are manufactured according to standard tolerances, then manufacturing ease is improved, but loosening occurs over time due to insufficient friction and deformation
Solution Approach 1:
The groove is pre-formed in the thread during manufacturing, preparing the structure for subsequent plastic deformation during the tightening process. This preliminary structural modification ensures that when the fastener is tightened, the thread will automatically deform to create the wedge effect and increase loosening resistance
Solution Approach 2:
The patent modifies the thread geometry parameter by adding a groove at the root, which changes the stress distribution and enables plastic deformation. This geometric modification is simple to manufacture and integrates seamlessly with standard threading processes
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
The groove in the fastener thread enables increased loosening resistance by allowing the thread to plastically deform and expand, effectively preventing the loosening of fastened materials, even under continued torque, by transferring tightening torque into axial force that enhances the wedge effect between the thread crests and roots.
Implementation Method 1
said groove is configured to allow said thread to deform and increase a major diameter of said thread due to an axial force
Implementation Method 2
providing enhanced loosening resistance through a wedge effect, thereby maintaining the tightened state
Data Source
AI summary
Disclosed is a fastener that includes a thread having a groove formed therein to provide a loosening resistance due to a deformation of the thread, the deformation resulting from a threshold axial force applied to the thread by a receiving structure.