Impact Wrench Axial Switching Mechanism

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Solution Overview

Problem

Existing impact wrenches lack a simple and efficient mechanism to switch between percussion and non-percussion modes, limiting their versatility in screwdriving and drilling applications.

Innovation Solution

An impact wrench design featuring an actuating means with a V-groove hammer mechanism and an axially displaceable adjusting ring or pin that allows for easy switching between operational modes by controlling the engagement and disengagement of the hammer and drive shaft, enabling both rotational and axial movements to facilitate torque delivery with or without percussion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switching mechanism is added to enable both percussion and non-percussion modes, then the versatility and adaptability of the impact wrench are improved, but the device complexity increases

Engineering Contradiction:
Improveoperating mode switchingVSAvoidswitching mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuating means combines multiple functions into a single component: it blocks the hammer's axial movement to disable percussion mode, and simultaneously blocks the relative rotational movement between hammer and drive shaft to enable non-percussion screwdriving mode. This merging of blocking functions into one actuating means reduces the number of separate components needed for mode switching.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuating means serves multiple purposes: it acts as both a percussion disablement mechanism and a rotational coupling mechanism. By designing the actuating means to perform both blocking functions, the patent achieves multi-functionality that reduces overall device complexity while maintaining versatility.

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

2Adaptability or versatility

If the hammer is constantly engaged with the anvil, then the impact function is blocked, but the rotary drive of the output shaft is also prevented

Engineering Contradiction:
Improveimpact function blockingVSAvoidrotary drive capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent separates the blocking of axial movement (for impact function) from the blocking of rotational movement (for rotary drive). The actuating means can block axial movement of the hammer independently while allowing rotational movement between the hammer and drive shaft, enabling selective disablement of percussion mode without preventing screwdriving operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The actuating means acts as an intermediary mechanism that selectively blocks only the axial movement of the hammer relative to the drive shaft, while permitting rotational movement. This selective blocking allows the hammer to remain engaged with the anvil for impact function while still enabling the drive shaft to rotate for screwdriving operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the actuating means blocks both axial and rotational movements, then the hammer is fixed, but the simplicity of the switching mechanism is reduced

Engineering Contradiction:
Improveswitching mechanism simplicityVSAvoidmode switching control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The actuating means merges the blocking of axial movement and rotational movement into a single actuating component. This consolidation maintains simplicity in the switching mechanism while providing comprehensive control over both types of movement, avoiding the need for separate actuating components for each blocking function.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables seamless switching between percussion and non-percussion modes, enhancing the tool's versatility for screwdriving and drilling tasks while reducing vibrations and improving torque control.

Implementation Method 1

The system receives kinetic energy from the drive side in the form of torque and speed, which is temporarily stored in an assembly such as a spring or a rotating mass

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The system receives kinetic energy from the drive side in the form of torque and speed, which is temporarily stored in an assembly such as a spring or a rotating mass

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

The control mechanism ensures that the energy is released to the anvil for a limited time so that the connection is released again when the stored energy has been released

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2140976B1Impact wrench
Publication Date: 2011.11.16 METABOWERKE
  • EP2140976B1 patent drawingFigure 1
  • EP2140976B1 patent drawingFigure 2
  • EP2140976B1 patent drawingFigure 3

AI summary

The wrench has an actuating unit (23) i.e. axially displaceable setting ring (22), for switching an impact mechanism between an operating mode in which the mechanism is switched on, and an operating mode in which the mechanism is switched off. The actuating unit is in rotationally fixed engagement with a drive shaft (30) or a hammer (20), or is not engaged with the hammer or the shaft, when the mechanism is switched on. The actuating unit is in rotationally fixed engagement with the hammer and the shaft, when the mechanism is switched off, and is axially movable to switch the mechanism.