Variable-Thread Knurl Fastener for Low-Torque Split-Resistant Binding
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Solution Overview
Problem
Conventional fasteners face challenges in securely and efficiently binding materials, particularly in materials like wood, where high torque is required for penetration and the risk of splitting or damage is high.
Innovation Solution
A fastener design featuring a shank with a contiguous helical thread having varying thread angles and serrated edges, along with knurls, which reduces the torque needed for installation and enhances material engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fasteners are used to bind materials securely, then binding strength is improved, but installation torque requirement increases and risk of material damage increases
Solution Approach 1:
The thread is segmented into multiple zones along the fastener length, with each zone having different thread angles (e.g., larger angle at tip for easy penetration, smaller angle in body for strong binding). This segmentation allows the fastener to optimize performance at different stages of installation and loading.
Solution Approach 2:
Different portions of the fastener have locally optimized properties: the tip region has larger thread angles and potentially serrated edges for penetration, while the body region has smaller thread angles for binding strength. Knurls are applied locally at specific positions to enhance grip without affecting the entire fastener.
2Reliability
If conventional fasteners are used to penetrate wood or composite materials, then material binding is achieved, but risk of splitting or damage increases
Solution Approach 1:
The fastener tip is pre-configured with larger thread angles and potentially serrated edges to facilitate easy penetration and create a pilot path through the material before the main body engages. This preliminary penetration action reduces the force needed and prevents sudden material failure.
Solution Approach 2:
The thread angle parameter is varied along the length of the fastener, with larger angles at the tip for penetration and smaller angles in the body for binding. This parameter change optimizes the balance between penetration capability and binding strength, reducing material stress and damage risk.
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 fastener design significantly reduces the torque required for installation and improves material binding, minimizing the risk of damage and enhancing the overall fastening performance.
Implementation Method 1
At least one knurl positioned in the shaft within an area of the first thread angle
Implementation Method 2
at least a portion of the contiguous helical thread including a serrated edge
Data Source
AI summary
A fastener includes a shank having a point at a first end and a second, head end. A first portion of a thread is formed with a first thread angle and a second portion of the thread is formed with a second thread angle. One or more knurls are provided in the shaft in the threaded or unthreaded regions of the fastener. The thread may be serrated or jagged over one or more portions of the fastener, including the area of the first thread angle.