Impact Tool Shock-Absorbing Element Durability via Intermediary

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Solution Overview

Problem

Existing impact tools suffer from reduced durability due to unnecessary stress on shock-absorbing elements caused by compressive loads and repeated impacts during no-load conditions, leading to progressive deterioration.

Innovation Solution

The impact tool incorporates a shock-absorbing element positioned without being press-fitted, with a washer and sleeve configuration that reduces stress by allowing the interjacent element to move within a sleeve, and a second shock-absorbing element between the sleeve and cylinder to absorb impacts, preventing direct contact and compressive stress on the primary shock-absorbing element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a shock-absorbing element is press-fitted in a recess to reduce impact under no-load conditions, then the impact noise and housing damage are reduced, but the shock-absorbing element is subjected to combined compressive loads that lower its durability

Engineering Contradiction:
Improveimpact noise and housing damageVSAvoiddurability of shock-absorbing element
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a stepped portion on the impactor that acts as an intermediary between the impactor and the shock-absorbing element. This stepped portion contacts the shock-absorbing element at a specific location during no-load conditions, allowing impact absorption while reducing the combined compressive loads on the shock-absorbing element, thereby improving its durability while maintaining impact noise reduction

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the interjacent element is allowed to move freely to maintain operational flexibility, then the tool can adapt to different loading conditions, but the interjacent element repeatedly contacts the stepped portion causing durability issues

Engineering Contradiction:
Improveadaptability to loading conditionsVSAvoiddurability of interjacent element and housing
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by providing a shock-absorbing element that proactively absorbs impacts during no-load conditions. This prevents the interjacent element from repeatedly contacting the stepped portion, thereby reducing wear and improving durability while maintaining the adaptability of the interjacent element for different loading conditions

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

This configuration enhances the durability of the shock-absorbing elements and maintains performance over a longer period by reducing stress and preventing direct contact with the interjacent element, thereby extending the tool's operational lifespan.

Implementation Method 1

a shock-absorbing element disposed frontward of the interjacent element within the housing... configured to absorb impacts, preventing direct contact and compressive stress on the primary shock-absorbing element

Methodology Applied
Scientific EffectImpact absorption: Damping

Data Source

PatentEP2105260B1Impact tool
Publication Date: 2012.02.29 MAKITA CORP
  • EP2105260B1 patent drawingFigure 1
  • EP2105260B1 patent drawingFigure 2

AI summary

A cushion ring (16) is disposed frontward of an interjacent element (20) within a housing (2) of an impact tool, and a washer (17) is disposed rearward of and adjacent to the shock-absorbing element (16). The interjacent element (20) is configured to come in contact with the washer (17) when the interjacent element (20) is caused to advance by an impactor's strike under no-load conditions. A sleeve (18) disposed rearward of and adjacent to the washer (17) is configured to position the cushion ring (16) and the washer (17), and to allow the interjacent element (20) to move rearward and frontward inside the sleeve (18).