Discontinuous Thread Ridge Locking Portion for Fastening
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Solution Overview
Problem
Existing threaded fastening systems require large forces for assembly and are prone to loosening due to the need for elastic deformation of continuous thread ridges, making them difficult to use and maintain.
Innovation Solution
A threaded member with a discontinuous helical thread ridge featuring locking portions with reduced flank angles and strategically positioned on the thread ridge, allowing for adjustable frictional force without requiring large assembly forces, and a fastening member and dart design incorporating these threaded members to prevent loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a continuous thread ridge is used for fastening, then the fastening strength is improved, but a large force is required for assembly and the thread ridge must be elastically deformed
Solution Approach 1:
The continuous thread ridge is divided into multiple discrete thread ridges separated by gaps. This segmentation allows each individual thread ridge to be elastically deformed during assembly without requiring deformation of the entire thread structure, thereby reducing the assembly force while maintaining fastening strength through the cumulative effect of multiple locked thread ridges.
2Ease of manufacture
If a basic ridge profile is used, then the manufacturing is simplified, but the fastening is prone to loosening due to clearance
Solution Approach 1:
While maintaining the basic ridge profile for most of the thread ridge to ensure ease of manufacture, the patent modifies specific local regions by adding locking portions with different flank angles. These localized modifications create elastic deformation capability and locking effects at critical positions, preventing loosening without requiring changes to the entire thread profile.
3Reliability
If locking portions with reduced flank angles are added to prevent loosening, then the fastening reliability is improved, but the device complexity increases
Solution Approach 1:
The locking portions are created by making the thread ridge asymmetric with different flank angles on opposite sides. One flank maintains the basic profile angle for compatibility and manufacturing, while the other flank has a reduced angle to create the locking effect. This asymmetric design prevents loosening through elastic deformation without requiring additional components or complex multi-angle thread forms throughout the entire structure.
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 solution enables secure fastening without needing large assembly forces and maintains locking effects, preventing loosening, while allowing for easy assembly and disassembly of the threaded members.
Implementation Method 1
a large frictional force is generated between a thread ridge of the threaded shank and a thread ridge of the threaded hole by elastic deformation
Implementation Method 2
a large frictional force is generated between one threaded member and the other threaded member by elastic deformation
Data Source
AI summary
A threaded member has a discontinuous helical thread ridge 15 on which a plurality of dividing portions 14 are formed in the middle. At least one of the discontinuous portions of the thread ridge 15, which is interposed between the dividing portions 14, is a locking portion 18 which is configured such that a flank angle of one flank, out of flanks on both sides of the thread ridge 15, is smaller than a flank angle of a flank corresponding to a basic ridge profile and at least part of the flank is disposed on an outside of the flank corresponding to the basic ridge profile.