Hand Tool Decoupling Arrangement for Torsional Vibration Isolation
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Solution Overview
Problem
Existing hand-held power tools, such as electric combination hammers, inadequately decouple the handle from torsional vibrations due to the superimposition of spring effects in both cushioning areas, resulting in significant vibration transmission along the second direction during operation.
Innovation Solution
The decoupling arrangement features a first spring-loaded bearing with significantly lower spring stiffness along the second direction, primarily isolating torsional vibrations through the second spring-loaded bearing, while the first bearing minimizes superimposition, ensuring effective decoupling and comfortable handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If both cushioning areas have spring-loaded bearings with significant spring stiffness, then the handle is well-supported and stable, but torsional vibrations are not adequately decoupled due to superimposition of spring effects
Solution Approach 1:
The first spring-loaded bearing is designed with significantly lower spring stiffness in the second direction (transverse to working axis) compared to the first direction (along working axis). This directional differentiation allows the bearing to provide stable support along the working axis while minimizing vibration transmission in the transverse direction, thereby resolving the contradiction between handle stability and vibration decoupling.
2Strength
If the first spring-loaded bearing has high spring stiffness in both directions, then the handle is firmly supported, but the decoupling of torsional vibrations is compromised due to superimposition of spring effects from both bearings
Solution Approach 1:
The spring stiffness parameter of the first spring-loaded bearing is specifically modified to be significantly lower in the second direction (transverse) than in the first direction (axial). This parameter change enables the bearing to maintain firm support strength along the working axis while effectively reducing vibration transmission in the transverse direction, thus resolving the contradiction between support strength and vibration isolation.
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 reduces vibration transmission to the handle, allowing for comfortable operation by isolating torsional vibrations primarily through the second spring-loaded bearing, enhancing the overall handling experience.
Implementation Method 1
The decoupling arrangement has a first spring-loaded bearing and a second spring-loaded bearing in the form of a rotary bearing
Implementation Method 2
a spring-loaded pivot bearing, on which a certain rotary movement of the handle relative to the housing against a spring force is made possible
Data Source
Figure 1
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AI summary
A hand tool (2) comprises a housing (4) in which a working element (10) is provided, which during operation is reciprocating along a working axis (A) spaced apart from a center of gravity (S) of the hand tool (2) and which is parallel to a first direction (z), and a handle (14) which is held on the housing (4) via a decoupling arrangement (16) comprising a first spring bearing (18) and a second spring bearing (20) which is spaced further away from the working axis (A) with respect to a second direction (y) perpendicular to the working axis (A) than the first spring bearing (18). The first spring bearing (18) is provided to have a lower spring stiffness along the second direction (y) than along the first direction (z).