Wood Screw With Convex Conical Tip And Double Thread
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Solution Overview
Problem
Existing wood screws face challenges in screwing behavior, requiring improvement in stability and resistance during insertion into workpieces, with existing designs often resulting in wobbling and increased resistance.
Innovation Solution
A wood screw design featuring a convex, conical tip section with a double-start thread and a chip breaker, where the first and second threads are offset by 180°, and cutting blades that reduce resistance and enhance stability, allowing for secure gripping and reduced wobbling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conical tip section is used, then the screw can be inserted into the workpiece, but the screwing behavior is unstable with increased resistance and wobbling
Solution Approach 1:
The tip section is divided into multiple functional zones: a first conical section with a first thread for initial penetration and positioning, and a second conical section with a second thread for enhanced gripping and stabilization. This segmentation allows each zone to perform its specific function optimally, reducing overall resistance and improving stability during screwing.
Solution Approach 2:
Different thread configurations are applied to different sections of the tip. The first thread has specific pitch and depth characteristics optimized for initial insertion, while the second thread has different characteristics optimized for stabilization and gripping. This local differentiation of thread quality enables the screw to overcome resistance more effectively at each stage of insertion.
2Productivity
If the core diameter increases rapidly in the tip section, then wood displacement is improved with fewer turns, but increased resistance is encountered at the beginning of screwing
Solution Approach 1:
The tip section is segmented into two conical zones with different diameter progression rates. The first conical section has a more gradual diameter increase that reduces initial resistance, while the second conical section has a steeper diameter increase that improves wood displacement efficiency. This segmentation allows the screw to balance between ease of insertion and displacement efficiency.
Solution Approach 2:
The first conical section with its first thread performs the preliminary action of penetrating the wood and establishing initial positioning with minimal resistance. Only after this preliminary penetration is achieved does the second conical section engage to provide the stronger gripping and stabilization, preventing the screw from encountering excessive resistance at the very beginning of insertion.
3Reliability
If a double-start thread is used in the tip section, then the screw grips securely after few turns and lateral stability is improved, but the thread design becomes more complex
Solution Approach 1:
Instead of implementing a complex double-start thread throughout the entire tip section, the invention segments the thread design: the first thread is provided in the first conical section, and the second thread is provided in the second conical section. This segmented approach achieves the stability benefits of a multi-start thread configuration while simplifying the overall design and manufacturing process compared to a true double-start thread.
Data Source
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AI summary
The invention relates to a wood screw (10) with a tip (12), a screw head (14), a shank (16) extending from the screw head (14) and transitioning into a convex conical tip section (18), wherein the tip section (18) forms the transition from the shank (16) to the tip (12), and a thread (26) extending into the tip section (18) via a cylindrical threaded shank section (20) adjacent to the tip section (18), and wherein the thread (26) is designed as a double thread in the area of the tip section (18).