Vibration Absorber Spring Guide Surface for Handheld Tools

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Solution Overview

Problem

Handheld power tools, such as rotary and chisel hammers, experience significant vibrations during operation, leading to user discomfort and fatigue, and existing vibration absorption technologies are either inefficient or require additional energy.

Innovation Solution

A vibration absorber device with an absorber mass and spring system, where the absorber spring is supported on both sides and guided by a spring guide surface, allowing for efficient energy storage and dissipation without additional energy input, and is designed to be compact and low-friction, with a rigid connection between the absorber spring and housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a vibration absorber device is added to reduce vibrations, then user comfort improves, but device complexity and weight increase

Engineering Contradiction:
Improvevibration transmission to userVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The absorber housing is integrated with the power tool housing, merging two structural components into one. This reduces the number of separate parts while maintaining the vibration absorption function, thereby improving user comfort without excessively increasing device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vibration absorption system is segmented into distinct functional components (absorber mass, absorber spring, absorber housing) that work together. This modular approach allows for targeted vibration reduction while keeping the overall structure manageable and not excessively complex

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If absorber mass is increased to store more kinetic energy, then vibration absorption performance improves, but device weight increases

Engineering Contradiction:
Improvevibration absorption performanceVSAvoidabsorber mass
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The spring stiffness parameter is optimized to work efficiently with a reduced absorber mass. By adjusting the spring constant and preloading force, the system achieves effective vibration absorption with less mass, thereby improving performance without proportionally increasing weight

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If spring guide surface is designed to enclose absorber spring by more than 45 degrees, then friction is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefriction lossVSAvoidspring guide surface angle
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The spring guide surface is designed with a specific geometric configuration (enclosing angle > 45 degrees) at the critical location where the spring contacts the housing. This localized geometric feature reduces friction where it matters most while not requiring high precision throughout the entire component

Inventive Principle:
Principle #3Local quality

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 significantly reduces vibrational energy transmission to the user, achieving a low-vibration operation with a compact design, high kinetic energy storage, and minimal friction, while being structurally simple and cost-effective.

Implementation Method 1

The absorber spring is advantageously designed to be elastically deformable in the spring direction by at least 25% of a length in the unloaded state

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an absorber spring, which supports the absorber mass on two opposite sides in a spring direction with forces which accelerate and/or decelerate the absorber mass

Methodology Applied
Scientific EffectHooke's Law: Hooke's Law

Implementation Method 3

an absorber mass, in particular which can be accelerated and/or decelerated by means of a spring force

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 4

Particularly low friction values can be achieved in a structurally simple manner

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2512749B1Handheld machine tool device
Publication Date: 2020.02.05 ROBERT BOSCH GMBH
  • EP2512749B1 patent drawingFigure 1
  • EP2512749B1 patent drawingFigure 2~3
  • EP2512749B1 patent drawingFigure 4

AI summary

The invention is based on a handheld machine tool device, in particular for a drill hammer and/or a chisel hammer, comprising at least one vibration-absorbing device (12a; 12b), which has at least one absorber mass (14a; 14b), an absorber housing (16a; 16b) and at least one absorber spring (18a, 20a; 18b, 20b), wherein the absorber spring (18a, 20a; 18b, 20b) is provided to support the absorber mass (14a; 14b) on two opposing sides in the spring direction (22a; 22b). According to the invention, the absorber housing (16a; 16b) has at least one spring guide surface (24a; 24b), which guides the absorber spring (18a, 20a; 18b, 20b) in the spring direction (22a; 22b) in at least one operating state.