Multi-Stage Decoupling Device for Handheld Hammer Drill Vibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing power tools fail to provide reliable vibration and oscillation decoupling when using an additional handle, leading to user fatigue during extended operations, especially in applications requiring increased force like corner drilling.

Innovation Solution

A multi-stage decoupling device with a vibration absorber is strategically placed between the main handle and the housing, featuring separate spring systems that engage differently based on the operating position, providing enhanced damping in the transition area between the handle and drive arrangement, allowing for effective vibration reduction and improved ergonomics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-stage decoupling device is used, then the structure is simple, but it cannot provide sufficient vibration damping when increased force is applied in compressor position

Engineering Contradiction:
Improvedecoupling device structureVSAvoidvibration damping reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The decoupling device is divided into multiple stages with different spring elements (first spring element, second spring element, third spring element) that engage sequentially based on the operating position and force applied. Each stage provides appropriate damping for its specific load condition, resolving the contradiction between structural simplicity and damping reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoupling device transitions from a static single-stage structure to a dynamic multi-stage structure where spring elements are selectively engaged based on operational conditions. The guide structure enables the second spring element to engage only in compressor position, allowing the system to adapt its damping characteristics to the applied load.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the decoupling device is arranged in the transition area between main handle and housing, then corner drilling capability is improved, but vibration damping for additional handle is insufficient

Engineering Contradiction:
Improvecorner drilling capabilityVSAvoidadditional handle vibration damping
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The decoupling device combines multiple damping functions into a single integrated structure located in the transition area. By incorporating multiple spring elements and a guide structure, it simultaneously provides damping for the main handle and additional handle while maintaining the compact positioning needed for corner drilling operations.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multi-stage spring elements are engaged, then vibration damping is enhanced, but the device length increases

Engineering Contradiction:
Improvevibration damping effectivenessVSAvoiddevice length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The multi-stage spring elements are arranged in a nested configuration where the second spring element is positioned to engage only when the first spring element is fully compressed. This nested arrangement allows multiple damping stages to be incorporated within a compact space, enhancing vibration damping without significantly increasing device length.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 solution enables longer operation without fatigue by effectively dampening vibrations, enhancing corner drilling capabilities, and allowing for easy assembly and retrofitting, while maintaining a compact design.

Implementation Method 1

a first spring element and a second spring element, each serving to support the main handle elastically

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a vibration absorber (15) is provided in the machine housing (10)... the weight reciprocates along the tool drive axis against the biasing force of the elastic member when the machine is actuated. By reciprocating the weight, the dynamic vibration reducer reduces vibrations generated in the body

Methodology Applied
Scientific EffectVibration absorption: Tuned Mass Damper

Implementation Method 3

at least one elastic element, the elastic element being arranged between the weight and the housing and serving to exert a prestressing force on the weight

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

Both the decoupling device and possibly a vibration absorber are preferably arranged in the transition area between the main handle and the drive arrangement or housing. As a result, the area in which the device is guided is significantly dampened with regard to oscillations and vibrations

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP2253430B1Electric tool machine, in particular handheld hammer drill
Publication Date: 2011.11.02 FRIEDRICH DUSS MASCHFAB GMBH
  • EP2253430B1 patent drawingFigure 1
  • EP2253430B1 patent drawingFigure 2
  • EP2253430B1 patent drawingFigure 3

AI summary

The tool has a drive arrangement (11) arranged in a housing (10) and provided for driving a tool holder around a drive axis. A main handle (13) is arranged at an end turned away from the holder and extends transverse to the drive axis. A decoupling device (14) is provided for partial vibration- and oscillation decoupling of the handle from the drive arrangement. A retainer attaches an additional handle (23) to the main handle, where the additional handle is decoupled by the decoupling device. The decoupling device and a vibration damper are accommodated in a damping unit.