Variable-Thread Fastener for Low-Torque Flush Binding
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Solution Overview
Problem
Existing fastener designs struggle to securely and efficiently bind materials, particularly in applications where a flush or embedded head is required, often requiring high torque for installation.
Innovation Solution
A fastener design featuring a shank with a blunt leading end, varying thread angles, serrated edges, and knurls, which reduces torque requirements by allowing self-boring into materials and enhancing grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fastener designs are used to securely bind materials, then binding strength is improved, but installation torque requirement increases
Solution Approach 1:
The thread is segmented into two distinct sections: a first section with a first thread angle and a second section with a second thread angle. This segmentation allows each section to perform different functions - the first section creates aggressive engagement and self-boring action, while the second section provides secure binding, thereby reducing overall installation torque while maintaining binding strength.
Solution Approach 2:
Different portions of the thread are given different local qualities through varying thread angles. The first section has a larger thread angle optimized for penetration and self-boring, while the second section has a smaller thread angle optimized for binding strength. This local differentiation resolves the contradiction between installation ease and binding strength.
2Productivity
If conventional fastener designs are used to bind materials securely, then binding efficiency is improved, but installation complexity increases
Solution Approach 1:
The first section of the thread with its specific thread angle and serrated edge configuration enables self-boring action, allowing the fastener to create its own path in the material without pre-drilling. This self-service capability simplifies installation procedures while maintaining binding efficiency.
3Shape
If conventional fastener designs are used for flush or embedded head applications, then head positioning is improved, but installation torque requirement increases
Solution Approach 1:
The threaded portion is divided into two sections with different thread angles, where the first section handles the high-torque penetration phase and the second section handles the lower-torque binding phase. This segmentation allows flush or embedded heads to be installed with reduced overall torque requirements while achieving proper head positioning.
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 design significantly reduces installation torque and improves binding efficiency, making it suitable for secure fastening in materials like wood and composites without the need for pre-drilling.
Implementation Method 1
the thread with the symmetric thread angle includes a serrated edge
Implementation Method 2
A contiguous helical thread formed from the tip toward the second end with a first, symmetric thread angle
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A fastener (400) includes a shank (402) having a first end (404) and a second end. A first portion (420) of a thread (412) is formed with a first, symmetric thread angle ( K) and a second portion (425) of the thread (412) is formed with a second, asymmetric thread angle (Δ, Λ ). The thread (412) may be serrated or jagged over one or more portions of the fastener (400), including the area of the symmetric thread angle ( K). A blunt end (455) comprises the leading end of the fastener (400).