Power Tool Grip Isolation Assembly for Multi-Axis Vibration

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Solution Overview

Problem

Power hand tools, such as reciprocating saws, generate significant vibrations that can be injurious to users, especially during prolonged use, and existing solutions like wobble plate drives and elastomer isolation are either ineffective or bulky, necessitating a more efficient vibration reduction method that does not increase costs.

Innovation Solution

A vibration isolation system utilizing elastomer pads and springs strategically positioned between the tool housing and the grip or handle, which decouples the user's hands from the tool's vibrations by absorbing and dissipating energy across multiple axes, providing adjustable stiffness and damping characteristics to minimize vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a wobble plate drive is used to translate rotational motion into reciprocating motion, then the tool can perform cutting operations, but significant vibration is generated that affects the user

Engineering Contradiction:
Improvecutting capabilityVSAvoidvibration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary vibration isolation system consisting of elastomeric elements and dampers positioned between the tool housing and the reciprocating mechanism. This mediator absorbs and dissipates vibration energy generated by the wobble plate drive, preventing it from being transmitted to the user's hands while allowing the cutting function to operate effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a counterweight driven by a secondary wobble plate is added to reduce vibration, then some vibration reduction is achieved, but the device becomes bulkier and more complex

Engineering Contradiction:
ImprovevibrationVSAvoidassembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the vibration reduction function from the traditional counterweight approach and implements it through a dedicated vibration isolation system using elastomeric elements and dampers. This separates the cutting function from the vibration control function, allowing each to be optimized independently without requiring a complex secondary wobble plate mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If elastomer isolation elements are trapped between the handle and tool housing, then some vibration isolation is achieved, but additional isolation is desired without increasing device bulk

Engineering Contradiction:
Improvevibration isolationVSAvoiddevice size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent employs flexible elastomeric elements and thin film dampers that provide effective vibration isolation in a space-efficient manner. These flexible components can be positioned within existing structural gaps between the handle and tool housing, providing enhanced vibration isolation without requiring additional bulk or volume in the device design.

Inventive Principle:
Principle #30Flexible shells and thin films

4Object-affected harmful factors

If existing vibration isolation methods are implemented, then some vibration reduction is achieved, but costs associated with vibration reduction increase

Engineering Contradiction:
ImprovevibrationVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent utilizes cost-effective elastomeric elements and standard dampers that can be easily manufactured and replaced if necessary. These components provide effective vibration isolation at a lower cost compared to more sophisticated active vibration control systems, making the solution economically viable for production.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 system effectively reduces user-experienced vibrations in power hand tools, enhancing control and comfort during use while maintaining a compact design and reducing costs associated with vibration reduction.

Implementation Method 1

A vibration isolation system utilizing elastomer pads and springs strategically positioned between the tool housing and the grip or handle, which decouples the user's hands from the tool's vibrations by absorbing and dissipating energy across multiple axes

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2969342B1Power hand tool with vibration isolation
Publication Date: 2021.05.12 ROBERT BOSCH GMBH
  • EP2969342B1 patent drawingFigure 1
  • EP2969342B1 patent drawingFigure 2~3
  • EP2969342B1 patent drawingFigure 4

AI summary

In one embodiment, a power hand tool includes a housing containing a working shaft, and a vibration isolation assembly, the vibration isolation assembly including at least one base member including a base portion fixed with respect to the housing, at least one vibration isolation portion including a first portion operably connected to the at least one base member, the at least one vibration isolation portion configured to isolate vibration in at least one direction, and a grip member having an outer surface configured to be gripped by a user and an inner surface operably connected to an outer portion of the at least one vibration isolation portion.