Crack-proof Screw with Segmented Threads for Wood
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Solution Overview
Problem
Conventional screws often cause cracking when used in materials like wood due to their design, which fails to effectively distribute the drilling force and prevent material damage.
Innovation Solution
A crack-proof screw design featuring a rod thread, expanding threads, and drilling threads, where the expanding threads are angled to distribute force efficiently and include a tapered tail with drilling threads to minimize force and prevent cracking, allowing for quick drilling with reduced force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional screw design is used, then the screw can be manufactured simply, but it causes cracking in wood materials due to concentrated drilling force
Solution Approach 1:
The screw thread is segmented into multiple types along the rod: drilling threads at the tip for initial penetration, expanding threads in the middle for material engagement, and rod threads at the top for fastening. This segmentation distributes the drilling and fastening functions to different sections, reducing concentrated force that causes cracking.
Solution Approach 2:
Different sections of the screw rod have different thread characteristics tailored to specific functions. The drilling threads have specific angles for easy penetration, the expanding threads have greater engagement angles for material holding, and the rod threads provide secure fastening. This local differentiation optimizes performance at each position while preventing overall material damage.
2Productivity
If conventional screw design is used, then the manufacturing process is simple, but the drilling speed is slow and requires excessive force
Solution Approach 1:
The drilling threads at the tip of the screw perform preliminary action by creating the initial hole path before the main body of the screw engages the material. This preliminary drilling action reduces resistance during subsequent insertion, enabling faster drilling with less force required.
Solution Approach 2:
The thread parameters (angles, pitch, depth) are optimized for different functions. The drilling threads have specific angle configurations that reduce drilling resistance and increase drilling speed, while the expanding threads have different parameters for material engagement. This parameter optimization achieves both fast drilling and reduced force requirements.
Data Source
AI summary
A crack-proof screw comprises a head; a rod having a first end extending from the head and having a rod thread near the head and expanding threads far away from the head; each expanding thread encircled through an angle smaller than 360 degrees; the screwing direction of the expanding thread being identical to or different from that of the rod thread; a tapered tail extending from a second end of the head; the expanding threads on the rod being near the tapered tail; the tapered tail having two drilling threads; each drilling thread can be extended to or not extended to the tip end of the tapered tail.