Wood Screw With Segmented Thread And Nibbed Head
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Solution Overview
Problem
Existing wood screws face challenges in self-drilling speed, torque to seat, and removal torque, necessitating a cost-effective configuration for quick and effective installation.
Innovation Solution
A wood screw design featuring a tapered end with a right-hand thread that includes notch regions and notch-free regions along its shank, along with frustoconical parts and outwardly protruding nibs at the head end, optimized for reduced resistance and enhanced cutting action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional continuous thread design is used, then the screw maintains continuous structural integrity, but self-drilling speed is reduced and torque to seat increases
Solution Approach 1:
The continuous thread is divided into discrete thread segments separated by notch regions. Each thread segment contains multiple notches that create discrete cutting edges, transforming the continuous threading into a segmented structure that enhances self-drilling capability while maintaining structural integrity through the periodic arrangement of thread segments
Solution Approach 2:
The thread structure transitions from uniform continuity to localized variation with notch regions strategically positioned along the shank. The notch-free regions provide continuous engagement while notch regions create cutting action, applying different functional qualities to different locations along the thread length to optimize both drilling speed and torque characteristics
2Force
If a conventional uniform thread design is used, then manufacturing is simplified, but torque to seat and removal torque are not optimized
Solution Approach 1:
The thread structure implements periodic alternation between notch-free regions and notch regions along the shank length. This periodic configuration creates alternating zones of continuous engagement and cutting action, optimizing the torque-to-seat characteristic through controlled periodic variation in thread geometry
Solution Approach 2:
The notch regions are pre-positioned along the thread to create predetermined cutting zones before the screw engages the material. This preliminary configuration of notches prepares the thread structure to perform cutting action at specific locations, reducing the torque required to seat the screw while maintaining manufacturing feasibility
3Ease of operation
If a standard frustoconical head design is used, then manufacturing is straightforward, but installation resistance is not minimized
Solution Approach 1:
The frustoconical head is segmented into multiple frustoconical parts with different taper angles arranged axially. This segmentation creates distinct zones for material displacement and screw engagement, reducing installation resistance through progressive material compression while maintaining structural integrity
Solution Approach 2:
Different frustoconical parts have different taper angles optimized for different functions: the first frustoconical part with a steeper angle for initial material displacement and the second frustoconical part with a gentler angle for final seating. This local differentiation of geometric properties optimizes installation ease without requiring complex overall head geometry
Data Source
AI summary
A screw includes at least one helical thread with a peripheral edge having notched regions spaced apart by notch-free regions. An underside of a head of the screw includes projecting nibs.