Segmented Screw Rod Thread Geometry for Debris Removal
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Solution Overview
Problem
Existing screws face challenges in efficiently removing debris during drilling and securing firmly to surfaces without retaining debris in the screwing hole.
Innovation Solution
A screw design featuring a large diameter screw rod with a smaller diameter tip end, where the first thread on the large rod has a larger diameter and potentially smaller pitch than the thread on the small rod, and a second thread is alternately arranged on the large rod, facilitating smooth debris removal and secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single diameter screw rod is used, then the manufacturing is simple, but the dregs removal efficiency is poor and debris remains in the screwing hole
Solution Approach 1:
The screw rod is divided into two distinct sections: a large diameter screw rod portion and a small diameter screw rod portion. This segmentation allows each section to perform different functions - the large diameter section effectively removes dregs during drilling while the small diameter section ensures proper thread engagement and debris evacuation, thereby improving dregs removal efficiency without requiring complex additional components
Solution Approach 2:
Different sections of the screw rod are given different local qualities through varying diameters. The large diameter portion provides enhanced cutting and dregs removal capability at the drilling front, while the small diameter portion optimizes thread formation and debris ejection. This local differentiation resolves the contradiction by tailoring each region's geometry to its specific functional requirements
2Speed
If a larger pitch angle is used, then the drilling speed increases, but the dregs removal becomes less efficient
Solution Approach 1:
The thread design is segmented into different pitch characteristics for different sections. The large diameter screw rod portion features a larger pitch angle that enables faster drilling speed and material removal, while the small diameter screw rod portion has a smaller pitch angle that optimizes thread engagement and facilitates efficient dregs ejection. This segmentation resolves the contradiction by allowing each section to optimize for its primary function
Solution Approach 2:
Different local pitch angles are applied to different sections of the screw rod. The large diameter section uses a larger pitch angle locally to maximize drilling speed, while the small diameter section uses a smaller pitch angle locally to ensure proper thread formation and effective debris removal. This local quality differentiation allows simultaneous optimization of both drilling speed and dregs removal efficiency
3Strength
If a single thread design is used, then the manufacturing is simple, but the securing firmness is insufficient
Solution Approach 1:
The thread configuration is segmented into multiple thread sections along the screw rod length. Different thread sections can have varying pitch, diameter, and depth characteristics that optimize engagement with the material being fastened. This multi-section thread design enhances securing firmness by creating multiple engagement zones while maintaining a relatively simple continuous thread structure that doesn't require complex assembly
Solution Approach 2:
Different local thread characteristics are applied to different sections of the screw rod. The thread depth, pitch, and diameter vary locally along the length of the screw rod to optimize engagement with the workpiece material. This local differentiation of thread properties enhances securing firmness through progressive engagement while maintaining a unified thread form that is straightforward to manufacture
Data Source
AI summary
A screw comprises an enlarged head; a large diameter screw rod having one end extending from the enlarged head; a small diameter screw rod having one end extending from another end of the large diameter screw rod; another end of the small diameter screw rod being formed as a tip end; a first thread extending from the large diameter screw rod and the small diameter screw rod; and the first thread extending to the tip end of the small diameter screw rod. A diameter of the first thread on the large diameter screw rod is large than that of the first thread on the small diameter screw rod. A pitch of the first thread on the large diameter screw rod is smaller than or equal to that of the first thread on the small diameter screw rod.