Triangular Hollow Screw Post Reinforcement
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Solution Overview
Problem
Screw posts prone to cracking due to excessive circumferential stress from chip accumulation between threads, and existing reinforcement designs increase manufacturing costs without efficiently addressing cracking issues, particularly at weld lines formed during injection molding.
Innovation Solution
A screw post design featuring an approximately triangular or polygon hollow structure with axially-extending reinforcement ribs that reduce chip accumulation and distribute stress more effectively, increasing the screw post's ability to withstand circumferential stress without the need for specialized self-tapping screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reinforcement ribs are added on the outer surface of the screw post, then the maximum circumferential stress that the screw post can withstand is increased, but the manufacturing cost increases and only partial reinforcement effect is achieved
Solution Approach 1:
The patent transitions from adding reinforcement ribs on the outer surface (external reinforcement) to creating an internally reinforced hollow structure with triangular or polygonal cross-section. This dimensional reconfiguration provides comprehensive stress distribution throughout the post body without adding external components, thereby reducing manufacturing complexity and cost while achieving superior reinforcement效果.
Solution Approach 2:
The hollow structure with triangular or polygonal cross-section concentrates structural strength at critical locations where circumferential stress is highest, rather than uniformly distributing reinforcement material throughout. This localized quality enhancement provides maximum strength where needed while minimizing material usage and manufacturing cost.
2Object-generated harmful factors
If cutting openings are formed at the bottom end of the self-tapping screw, then chip accumulation is reduced, but the manufacturing cost increases
Solution Approach 1:
Instead of adding cutting openings to remove chips, the patent utilizes the angular spaces created by the triangular or polygonal hollow structure to naturally contain and manage chips. The harmful chip accumulation is converted into a beneficial chip-containing feature that reduces circumferential stress without requiring additional manufacturing steps or increasing production cost.
Solution Approach 2:
Rather than modifying the self-tapping screw to prevent chip accumulation (as in prior art), the patent inverts the approach by designing the screw post's internal hollow structure to actively manage chips. This reversal of the problem-solving approach eliminates the need for costly modifications to the screw while achieving the same chip management benefit.
3Productivity
If the screw post is formed by injection molding, then manufacturing efficiency is high, but weld lines are formed at positions of lower structural strength causing easy cracking
Solution Approach 1:
The triangular or polygonal hollow structure strategically positions structural reinforcement at critical locations where weld lines form during injection molding. By concentrating material density and structural strength at these specific high-stress zones, the design compensates for the inherent weakness at weld line positions while maintaining overall manufacturing efficiency through a single-shot molding process.
Solution Approach 2:
The screw post employs a composite structural design combining the hollow triangular/polygonal cross-section with strategically placed rib structures within the molded body. This composite approach creates zones of enhanced strength that can be positioned to coincide with weld line locations, thereby reinforcing these vulnerable areas without requiring secondary operations that would reduce productivity.
Data Source
AI summary
A screw post is detachably screwed with a self-tapping screw. The screw post includes a post body and a rib structure. The post body has an approximately triangular hollow structure formed therein. The approximately triangular hollow structure has three arc-shaped sides. The rib structure protrudes from an outer surface of the post body corresponding to at least one of the three arc-shaped sides in an axially-extending manner. The self-tapping screw is screwed into the approximately triangular hollow structure.