Ribbed Screw Head Structure for Higher Pull-Out Resistance
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Solution Overview
Problem
Existing screws face issues with loosening due to vibrations, frequent use, and corrosion, leading to low pull-out resistance and instability in structures under load.
Innovation Solution
A screw design featuring a frustoconical portion with an annular recess and radial ribs that engage with the part to be fixed, providing improved pull-out resistance and fixation, while the frustoconical shape shields the ribs from damage during insertion and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing screws are used, then they can be easily inserted and removed, but they become loosened due to vibrations, frequent use, or corrosion, leading to low pull-out resistance
Solution Approach 1:
The head is segmented into multiple functional portions: a top portion for tool engagement, a frustoconical portion for shielding and structural support, and an annular recess for rib placement. This segmentation allows each portion to perform its specific function optimally while contributing to overall reliability
Solution Approach 2:
Radial ribs are added to the head structure, extending from the annular recess toward the shank. These ribs project radially outward to engage with the workpiece, creating additional engagement points that significantly improve pull-out resistance without substantially increasing overall head complexity
2Strength
If existing screws are used, then they have simple structure, but they are susceptible to loosening and provide poor fixation under load
Solution Approach 1:
The radial ribs are pre-positioned in the annular recess of the frustoconical head portion before insertion. Upon insertion, these ribs automatically engage with the workpiece surface, creating immediate mechanical interlocking that prevents loosening due to vibrations or frequent use
Solution Approach 2:
The head combines different geometric forms (top portion, frustoconical portion, annular recess) with radial ribs to create a composite structure that integrates multiple functions: structural support, shielding, and enhanced engagement, all within a unified head design
3Reliability
If the screw head has simple design, then it is easy to manufacture, but it provides insufficient contact and engagement with the part to be fixated
Solution Approach 1:
The head is divided into distinct segments (top portion, frustoconical portion, annular recess) that can be manufactured separately or as a unified piece, with each segment serving a specific function. The radial ribs are integrated into this segmented structure, providing enhanced contact without requiring complex assembly steps
Solution Approach 2:
The frustoconical portion provides localized shielding for the radial ribs during insertion and rotation, while the annular recess provides localized engagement with the workpiece. This local differentiation of functions allows the head to perform multiple roles without requiring complex overall structure
Data Source
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AI summary
A screw, comprising a head and a tip at opposite ends, and a shank extending between the head and the tip, the head comprising: a top portion, and a frustoconical portion arranged between the top portion and the shank, wherein the frustoconical portion comprises a step defining an annular recess towards the shank; and at least one radial rib arranged in the recess and extending towards the shank.