Impact Tool Vibration Reducing Member Positioning

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Solution Overview

Problem

Existing impact tools that rectilinearly drive tool bits via a swinging member do not adequately reduce vibrations, particularly during strong pressing operations, where vibration reduction is crucial.

Innovation Solution

The impact tool incorporates a vibration reducing member, including a dynamic vibration reducer with a weight that moves rectilinearly under an elastic biasing force, and a swinging member that rotates and swings in the axial direction, positioned close to the tool bit's working axis to enhance vibration reduction. This setup actively drives the weight to counteract vibrations, ensuring effective vibration reduction regardless of the vibration magnitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a dynamic vibration reducer is provided in the impact tool, then vibration reduction function is provided, but the vibration reducing performance is insufficient under high vibration conditions

Engineering Contradiction:
ImprovevibrationVSAvoidvibration reducing performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies mechanical vibration principles by introducing a vibration reducing member that generates counter-vibration to cancel the harmful vibrations during hammering operation. The vibration reducing member is specifically positioned to create opposing vibrational forces that neutralize the impact vibrations transmitted to the tool body.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The vibration reducing member functions as a counterweight mechanism, positioned on the opposite side of the working axis from the rotating shaft. This counterweight arrangement creates balanced forces that offset the unbalanced vibrations generated by the swinging member during impact operation.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Object-affected harmful factors

If the vibration reducing member is positioned away from the axis of vibration, then the structure is simplified, but the vibration reducing performance deteriorates

Engineering Contradiction:
Improvevibration amplitudeVSAvoidpositioning structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning the vibration reducing member at a specific location close to the axis of vibration where it can most effectively counteract the harmful vibrations. This localized positioning optimizes the vibration reduction effect at the critical area without requiring complex overall structural changes.

Inventive Principle:
Principle #3Local quality

3Productivity

If the impact tool operates under strong pressing force, then productivity increases, but vibration magnitude increases making vibration reduction more difficult

Engineering Contradiction:
Improvehammering efficiencyVSAvoidvibration magnitude
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The vibration reducing member provides preliminary anti-action by continuously generating counter-vibrations that oppose the harmful vibrations before they can fully propagate through the tool body. This preemptive vibration cancellation works effectively regardless of the magnitude of the pressing force applied during hammering operation.

Inventive Principle:
Principle #9Preliminary anti-action

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 improves vibration reduction performance by positioning the vibration reducing member close to the axis of maximum vibration amplitude, ensuring effective operation even under high vibration conditions, such as strong pressing forces, and prevents unintentional striking movements during drilling mode.

Implementation Method 1

a weight which rectilinearly moves in the axial direction of the tool bit under a biasing force of an elastic element

Methodology Applied
Scientific EffectElastic biasing force: Elasticity

Implementation Method 2

the dynamic vibration reducer forcibly drives the weight and thereby reduces vibration caused during operation of the tool bit

Methodology Applied
Scientific EffectDynamic vibration reduction: Damping

Data Source

PatentEP2428323B1Impact tool
Publication Date: 2016.11.16 MAKITA CORP
  • EP2428323B1 patent drawingFigure 1
  • EP2428323B1 patent drawingFigure 2
  • EP2428323B1 patent drawingFigure 3~4

AI summary

A technique for further improving vibration reducing performance is provided in an impact tool that rectilinearly drives a tool bit in an axial direction of the tool bit via a swinging member. An impact tool includes a motor 111, a rotating shaft 125 rotationally driven by the motor 111, a swinging member 129 that swings in the axial direction of a tool bit 119 by rotation of the rotating shaft 125, a tool driving mechanism 141, 143, 145 that is connected to an end region of the swinging member 129 in a direction transverse to the axis of the rotating shaft 125, and is caused to rectilinearly move in the axial direction of the tool bit 119 by swinging movement of the swinging member 129, thereby rectilinearly driving the tool bit 119, and a vibration reducing member 151 for reducing vibration caused in the axial direction of the tool bit 119 during operation of the tool bit 119. The vibration reducing member 151 is disposed on an opposite side of a rectilinear working axis of the tool bit 119 from the rotating shaft 125 and connected to a connecting part between the swinging member 129 and the tool driving mechanism 141, 143, 145 in such a manner as to be driven.