Oscillation Damper for Hand-Held Power Tool
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Solution Overview
Problem
Existing hand-held power tools, such as rotary hammers and chipping hammers, face challenges in effectively reducing vibrations during operation without unnecessary activation when there is no contact pressure, leading to inefficient vibration damping.
Innovation Solution
A structurally simple vibration damper system that is actively excited by an axially displaceable excitation means when the die is in the working position, using a ring-shaped excitation mechanism that surrounds the guide tube, allowing for passive operation during idle strokes and compact design for space-saving placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vibration damper is continuously active, then vibration reduction is maintained, but energy is wasted during idle strokes when no contact pressure exists
Solution Approach 1:
The vibration damper is activated periodically only during impact strokes when contact pressure is detected, and deactivated during idle strokes. The excitation means is displaceable axially to engage the oscillating mass only when needed, creating a periodic activation pattern that matches the operational cycle of the power tool.
Solution Approach 2:
The system uses contact pressure detection as feedback to control the activation state of the vibration damper. When contact pressure is detected during impact strokes, the damper is activated; when no contact pressure exists during idle strokes, the damper is deactivated. This feedback mechanism ensures energy-efficient operation while maintaining vibration reduction effectiveness.
2Reliability
If the excitation means is designed to surround the guide tube, then direct contact with the die is achieved for reliable excitation, but the structure becomes more complex
Solution Approach 1:
The ring-shaped excitation means serves multiple functions: it provides direct contact with the die for reliable excitation transmission, surrounds the guide tube for structural integration, and acts as a control element for activating the vibration damper. This multi-functional design achieves reliable excitation without proportionally increasing structural complexity.
Solution Approach 2:
The ring-shaped excitation means is nested around the guide tube, with the oscillating mass positioned within the ring structure. This nested arrangement allows compact integration of multiple components in a space-efficient manner, reducing overall structural complexity while maintaining functional effectiveness.
3Device complexity
If passive vibration absorbers are used, then the structure is simpler, but they cannot be deactivated when not needed
Solution Approach 1:
The vibration absorber is designed with an oscillating mass that can dynamically transition between passive and active states. The excitation means is axially displaceable to engage or disengage from the oscillating mass, allowing the system to switch between passive (energy-efficient during idle strokes) and active (effective vibration reduction during impact strokes) modes.
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 solution ensures efficient vibration reduction during tool operation with contact pressure while deactivating the damper during idle strokes, preventing unnecessary activation and maintaining tool functionality without inclinations or bends.
Implementation Method 1
which is axially pressure-biased to the housing via at least one spring
Implementation Method 2
A vibration damper is an oscillating subsystem, which consists of an abstract oscillating mass, an abstract spring and an abstract damper
Implementation Method 3
The abstract damper in particular is often not realized as a concrete component and is nevertheless effective due to the friction and flow losses that practically always occur
Data Source
Figure 1~2
AI summary
A hand-held power tool (1) with a housing (2) and an air spring impact mechanism (3) with an impact piston (4) which strikes a hammer (5), has at least one vibration damper (6) with a vibrating damper mass (7) which is axially compressed to the housing (2) via at least one spring (8a), wherein the vibration damper (6) can be actively excited by the hammer (5) in the working position via an axially movable excitation means (9).