Screw Head Pressing Structure for Washer Wear and Slip Prevention
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Solution Overview
Problem
Conventional screw structures with washers often experience wear, slipping, and reduced sealing effectiveness due to misalignment and frequent rubbing, leading to gaps and leakage when tightened into articles.
Innovation Solution
A screw structure with a shank and flange featuring trapezium-shaped pressing portions that apply force to the washer, causing elastic deformation and guiding it along inclined faces to prevent rotation and slipping, ensuring a secure and airtight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the screw and washer are not disposed at a parallel state, then the screw can be easily installed, but the washer is easily deflected and produces gaps reducing sealing effect
Solution Approach 1:
The pressing portions are pre-configured on the screw head to automatically apply pressing force to the washer during the screwing operation. This preliminary action ensures the washer maintains proper alignment and parallelism with the screw head from the beginning of installation, preventing deflection and gap formation that would compromise sealing.
2Strength
If the screw is tightened and locked onto the article, then the screw provides strong fastening, but the washer is easily worn out due to frequent rubbing
Solution Approach 1:
The pressing function is extracted from the washer and integrated directly into the screw head through the pressing portions. This eliminates the need for the washer to provide pressing force, reducing its mechanical stress and rubbing wear, thereby extending its service life while maintaining strong fastening through the screw's direct pressing action.
Solution Approach 2:
The pressing function is merged from the washer into the screw head structure. The pressing portions are formed as an integral part of the screw head, combining the fastening and sealing functions in one component, which reduces wear on the washer and extends its durability.
3Productivity
If the screw is rotated during installation, then the screw can be tightened, but the washer easily slips out during rotation
Solution Approach 1:
The pressing portions apply preliminary pressing force to the washer in the direction opposite to potential slippage during screw rotation. This counteracting force prevents the washer from slipping out during the tightening operation, ensuring reliable retention while maintaining installation efficiency.
4Reliability
If the washer is pushed by the screw to touch the article, then the washer provides sealing effect, but gaps form between screw and washer reducing airtight effect
Solution Approach 1:
The pressing function is merged from the washer into the screw head structure. The pressing portions are formed as an integral part of the screw head, combining the fastening and sealing functions in one component, which reduces wear on the washer and extends its durability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The screw structure enhances the sealing effect by preventing washer rotation and slipping, reducing wear, and maintaining an airtight seal by deforming the washer elastically and increasing drag, thus preventing ambient air or liquid from entering the article.
Implementation Method 1
the pressing portions of the screw apply a force on the washer so that the washer is deformed elastically, thereby enhancing the sealing effect of the washer
Data Source
AI summary
A screw structure includes a screw and a washer mounted on the screw. The bottom face of the screw head is provided with a plurality of pressing portions. Each of the pressing portions has a top provided with a first plane and a bottom provided with a second plane having an area smaller than that of the first plane. Each of the pressing portions is provided with a first inclined face and a first steep arcuate face. The first inclined face is directed toward a clockwise direction of the screw when the screw is screwed. The first steep arcuate face is directed toward the external thread. When the screw is screwed into an article, the pressing portions press the washer, and an outer diameter of the washer is expanded outward and forms an expansion.