Impact Tool Compression Spring Absorbs Reaction Force

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing impact tools do not effectively reduce reaction forces during hammering operations, leading to increased vibration and potential dislodgment of components, which complicates the design and usage.

Innovation Solution

Incorporating a compression coil spring that absorbs reaction forces by elastically deforming, combined with a cylindrical member that transmits reaction forces to the spring, eliminating the need for additional locking mechanisms and simplifying the structure by integrating the spring and cylinder as a single component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a cushioning member (rubber ring) is disposed between the tool body and impact bolt to reduce reaction force, then the reaction force reduction effect is partially achieved, but the structure becomes more complex and requires additional locking mechanisms

Engineering Contradiction:
Improvereaction force reductionVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the cushioning member and locking mechanism into a single integrated structure. The cushioning member is disposed between the tool body and impact bolt while simultaneously serving as a locking element, eliminating the need for separate locking mechanisms and reducing overall structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cushioning member is designed to perform multiple functions: it cushions the reaction force during hammering operation and simultaneously prevents the impact bolt from dislodging. This multi-functional design reduces the number of components needed while maintaining both reaction force reduction and structural stability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If the cylinder is held in the housing part using biasing force from the compression coil spring, then the structure is simplified and locking means are eliminated, but the cylinder may become dislodged during operation

Engineering Contradiction:
Improvestructural simplificationVSAvoidcylinder retention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The compression coil spring is pre-loaded to exert a biasing force on the cylinder before hammering operation begins. This preliminary action ensures the cylinder is firmly held in the housing part, preventing dislodgment during subsequent high-impact operations while maintaining structural simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The compression coil spring provides a counteracting biasing force that balances the forces attempting to dislodge the cylinder during hammering. This counterforce mechanism reliably retains the cylinder without requiring complex locking structures

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

3Length of moving object

If the compression coil spring is disposed outside the cylinder, then the axial length of the impact tool is reduced, but the spring requires additional locking mechanisms to prevent movement

Engineering Contradiction:
Improveaxial lengthVSAvoidlocking mechanism requirements
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent integrates the locking function into the existing cylindrical structure by forming locking grooves on the outer surface of the cylinder that engage with corresponding protrusions on the housing part. This merging of locking functionality with the existing structure eliminates additional locking mechanisms while maintaining compact axial dimensions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cylinder's own geometric features (locking grooves and protrusions) provide the locking function, making the system self-locking without requiring external locking mechanisms. This self-service approach maintains compact size while ensuring reliable retention

Inventive Principle:
Principle #25Self-service

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 significantly reduces vibration and enhances the effectiveness of reducing reaction forces during hammering, simplifies the tool's structure, and facilitates easier mounting and dismounting of components.

Implementation Method 1

the compression coil spring absorbs a reaction force which is caused by rebound from the workpiece and which acts on the hammer actuating member when the hammer actuating member performs a hammering operation on the workpiece

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1992452B1Impact tool
Publication Date: 2011.09.21 MAKITA CORP
  • EP1992452B1 patent drawingFigure 1
  • EP1992452B1 patent drawingFigure 2
  • EP1992452B1 patent drawingFigure 3

AI summary

A representative impact tool comprises a tool body (103), a hammer actuating member (145,119), a cylinder (141) and a compression coil spring (171). The compression coil spring (171) contacts the hammer actuating member (145,119) and thereby positions the tool body (103) with respect to the workpiece when the hammer actuating member (145,119) is pressed against the workpiece and pushed rearward in advance of the hammering operation. In such position, the compression coil spring (171) absorbs a reaction force that is caused by rebound from the workpiece and acts upon the hammer actuating member (145,119) when the hammer actuating member (145,119) performs the hammering operation on the workpiece. The cylinder (141) is inserted into the tool body (103) from the front along the axial direction of the hammer actuating member (145,119) and thereby housed within a predetermined housing part of the tool body (103). The compression coil (171) spring applies a biasing force to the cylinder (141) in a rearward direction and thereby holds the cylinder (141) in the housing part.