Impact Mechanism Center of Gravity Alignment

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Solution Overview

Problem

Impact wrenches with rebounding impact mechanisms generate high levels of vibrations, which are harmful to users and lead to musculoskeletal and other health issues, while existing solutions fail to adequately mitigate these vibrations.

Innovation Solution

The implementation of anti-vibration means in the impact mechanism, where the center of gravity is positioned substantially on the axis of rotation, and the axis of rotation is a main axis of inertia, reducing or eliminating vibrations during all phases of operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a rebounding impact mechanism is used to generate high impact torque, then the tightening/loosening efficiency is improved, but high level of vibrations is generated which is harmful to users

Engineering Contradiction:
Improvetightening/loosening efficiencyVSAvoidvibration level
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the counterweight principle by positioning the center of gravity of the impact mechanism on its axis of rotation and ensuring the axis of rotation is a main axis of inertia. This configuration creates a counterbalancing effect that reduces or eliminates vibrations generated during impact operations, allowing high impact torque to be delivered without exposing users to harmful vibration levels

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

2Power

If the striking element rotates through more than half a revolution before impact, then the impact energy is increased, but the device complexity increases

Engineering Contradiction:
Improveimpact energyVSAvoidmechanism complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent employs the dynamics principle by allowing the striking element to rotate through more than half a revolution (specifically through at least 200°) before impact. This dynamic rotation path enables the striking element to accumulate greater kinetic energy and deliver more powerful impacts, while the mechanism remains manageable in complexity through proper design of the rotating components

Inventive Principle:
Principle #15Dynamics

3Object-generated harmful factors

If the center of gravity is positioned on the axis of rotation, then the vibration level is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvevibration levelVSAvoidcenter of gravity positioning precision
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies the self-service principle where the impact mechanism's own mass distribution and geometric configuration automatically ensure that the center of gravity is positioned on the axis of rotation and that the axis of rotation coincides with a main axis of inertia. This self-configuring design reduces vibration without requiring external adjustment mechanisms or excessively tight manufacturing tolerances

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 or eliminates the level of vibrations perceived by the user, enhancing comfort and reducing the risk of health issues associated with vibration exposure.

Implementation Method 1

the center of gravity of the impact mechanism is substantially positioned on said axis of rotation

Methodology Applied
Scientific EffectCenter of gravity positioning: Gravitation

Implementation Method 2

said axis of rotation of the impact mechanism is substantially one of its main axes of inertia

Methodology Applied
Scientific EffectMoment of inertia: Moment of Inertia

Implementation Method 3

said striking system being configured to be rotated, along said axis of rotation, through at least 200° before the impact

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 4

the striking element is brought into collision with the output square to generate an impact torque

Methodology Applied
Scientific EffectKinetic energy accumulation:

Data Source

PatentEP3842184B1Shock key with impact mechanism
Publication Date: 2024.10.23 ETABLISSEMENT GEORGES RENAULT SAS
  • EP3842184B1 patent drawingFigure 1~3
  • EP3842184B1 patent drawingFigure 4~6
  • EP3842184B1 patent drawingFigure 7~9

AI summary

The present invention relates to a screwing/unscrewing tool comprising: - a motor - an impact mechanism (110, 200, 310, 410, 710, 810), driven by said motor along an axis of rotation (AR) and held fixed in translation along said axis of rotation (AR), comprising: - an impact system comprising an impact element (1112, 2112, 3112A-B, 4112A-C, 7112A-D, 8112A-E), - an output square (112, 312, 412) comprising an impact receiving element (1121, 2121, 3121A-B, 4121A-C), the impact element (1112, 2112, 3112A-B, 4112A-C, 7112A-D, 8112A-E) being configured to come into contact with the impact receiving element (1121, 2121, 3121A-B, 4121A-C) to generate an impact torque, said impact system being configured to be driven in rotation, about the axis of rotation (AR), over at least 200° before impact.According to the invention, the impact mechanism (110, 200, 310, 410, 710, 810) includes anti-vibration means configured so that, at least during an impact, the center of gravity (G1, G2, G4, G3, G7) of the impact mechanism (110, 200, 310, 410, 710, 810) is substantially positioned on said axis of rotation (AR), and said axis of rotation (AR) of the impact mechanism (110, 200, 310, 410, 710, 810) is substantially one of its principal axes of inertia.