Anti-Vibration Element With Threaded Dome Spring
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Solution Overview
Problem
Existing hand-held power tools with anti-vibration elements face challenges due to the dependence on temperature and moisture for elastomeric materials and high manufacturing costs for metallic components, while current non-linear spring characteristics do not effectively manage both axial and transverse loads efficiently.
Innovation Solution
A hand-held power tool with an anti-vibration element featuring a spring wire coil oriented along the vibration axis, wound onto a threaded dome with a preload area where the intermediate pitch is greater than the spring wire diameter, providing a linear, flat central load range and a steeper characteristic curve in high load ranges, and a tapered convex core for transverse loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomeric hollow cylinder is used as anti-vibration element, then vibration damping is achieved, but dependence on temperature and moisture increases
Solution Approach 1:
The patent replaces the complex elastomeric hollow cylinder with a simple spring wire coil that can be easily manufactured and replaced if needed. The spring wire coil provides adequate vibration damping without the temperature and moisture dependence of elastomeric materials, effectively treating the elastomer as a problematic component to be avoided.
Solution Approach 2:
The patent changes the material parameter from elastomeric to metallic spring wire, fundamentally altering the physical properties. This substitution eliminates the temperature and moisture sensitivity inherent in elastomers while maintaining the vibration damping function through the spring's elastic properties.
2Reliability
If a metallic leaf spring hollow cylinder is used as anti-vibration element, then vibration damping is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the anti-vibration function into two separate components: a simple spring wire coil for vibration damping and a separate threaded dome for preload application. This segmentation allows each component to be manufactured independently using simple processes, avoiding the need for complex integrated structures like hollow cylinders.
Solution Approach 2:
The patent uses a simple spring wire coil instead of a complex metallic hollow cylinder. The spring wire coil can be manufactured using standard coil spring processes and is significantly simpler and cheaper to produce, while providing adequate vibration damping performance.
3Reliability
If current non-linear spring characteristic is used, then vibration damping is improved, but ability to manage both axial and transverse loads efficiently is reduced
Solution Approach 1:
The patent designs the spring wire coil with a threaded dome that can handle both axial and transverse loads. The threaded dome structure provides preload in the axial direction while also restricting transverse movement, making the anti-vibration element universal for handling multiple load directions rather than specialized for one.
Solution Approach 2:
The patent applies preliminary compressive prestress to the spring wire coil through the threaded dome. This preload is applied before operation to pre-compress the spring, which improves vibration damping by reducing the spring's natural frequency and preventing unwanted movement during operation.
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
This design effectively decouples vibrations, maintaining resilience in low loads, progressively increasing in high loads, and ensuring linear steepness in the highest load range, while being cost-effective and adaptable to both axial and transverse loads.
Implementation Method 1
The anti-vibration element (1) has a spring wire coil (7) oriented along the vibration axis (A) with a plurality of turns (2)
Implementation Method 2
the spring wire coil (7) rests with different turns (2) on both contact surfaces (14) of the external thread (4) with contact surfaces (14) on both sides axially
Data Source
Figure 1~2
Figure 3~4
AI summary
The tool has a sub-assembly (5) that vibrates along a vibration axis. An anti-vibration element (1) vibrationally decouples a handle sub-assembly (6) from the sub-assembly (5) and has a coil spring (7) formed of a spring wire. A threaded plug (3) is provided with an outer thread (4). The coil spring (7) has a set of windings (2) extending along a preload region (V) and screwed on the outer thread under an axial compressive preload. The outer thread has an intermediate-channel width (Z) greater than diameter (D) of the wire, and has a spring-side contact surface having a non-linear pitch.