Threaded Fastener With Variable Apex Angle for Vibration Resistance
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Solution Overview
Problem
Existing threaded fastening elements for vehicle equipment, such as screws, face challenges in easy installation and reliable retention of assembled parts, particularly in materials like sheet metal, where they often require high torque and struggle with vibrations.
Innovation Solution
A self-tapping or self-forming threaded fastener with a thread that gradually decreases its apex angle from a first to a second angle, facilitating easy insertion and progressive tightening, combined with a tapered free end for improved centering and reduced thread formation torque, ensuring durable fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional threaded fastening element is used, then the fastener can be installed, but it requires high torque and struggles with vibrations
Solution Approach 1:
The thread apex angle is made variable along the thread length rather than constant. The apex angle transitions from a first angle (e.g., 60°) at the thread start to a second angle (e.g., 30°) at the thread end, creating a dynamic geometric progression that adapts the thread geometry during the fastening process to reduce torque and improve vibration resistance
Solution Approach 2:
The geometric parameters of the thread, specifically the apex angle, are changed progressively along the thread length. This parameter variation allows the thread to progressively engage the material, reducing the torque required for installation while maintaining reliable retention under vibration through the optimized angle transition
2Adaptability or versatility
If a self-tapping or self-forming threaded fastener is used, then the fastener can form its own thread, but it requires high torque for thread formation
Solution Approach 1:
The variable apex angle creates a dynamic thread geometry that progressively engages the material during self-tapping. The transition from a larger initial angle to a smaller final angle allows the thread to gradually form the material, reducing the peak torque required compared to conventional self-tapping screws with constant angles
Solution Approach 2:
By changing the apex angle parameter along the thread length, the patent optimizes the thread formation process. The initial larger angle facilitates material displacement, while the progressively smaller angle reduces resistance during thread formation, thereby reducing the overall torque requirement for self-tapping
3Device complexity
If a thread with constant apex angle is used, then the thread geometry is simple, but it cannot progressively reduce torque during tightening
Solution Approach 1:
The thread geometry transitions from static (constant angle) to dynamic (variable angle). The apex angle changes progressively along the thread length, creating a dynamic geometric progression that automatically reduces torque during the tightening process without requiring complex external mechanisms
Solution Approach 2:
The patent applies parameter changes by varying the apex angle along the thread length. This creates a gradient in thread geometry where the angle transitions from a first value to a second value, enabling progressive torque reduction during tightening while maintaining relatively simple manufacturing through a systematic geometric progression
Data Source
Figure 1
AI summary
This threaded fastening element (2) comprises a threading (14) extending along a central axis (A), the threading (14) having at least one thread having an apex angle that gradually reduces, continuously and monotonously, between a first apex angle (a1) and a second apex angle (a2) strictly smaller than the first apex angle. The threaded fastening element is a screw or a nut.