Integrated Actuating Element for Electric Hand Tool Braking

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Solution Overview

Problem

Existing electric hand-held power tools with braking devices require multiple manual actuating elements, increasing complexity and reducing user convenience, while also risking premature wear of both the braking device and drive unit due to simultaneous operation.

Innovation Solution

A single manual actuating element combines switch-on/off functionality with braking device activation/deactivation, incorporating a switch-on lock to prevent drive unit activation when the braking device is engaged, ensuring safe operation and extended component lifespan by allowing drive unit activation only when the braking device is deactivated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple manual actuating elements are provided for separate control of drive unit and braking device, then operational safety is improved, but device complexity increases and ease of operation deteriorates

Engineering Contradiction:
Improveoperational safetyVSAvoidnumber of actuating elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the manual actuating element for the drive unit and the manual actuating element for the braking device into a single integrated actuating element. This single element can be operated in different positions to control both the drive unit switching and the braking device activation, thereby reducing the total number of actuating elements while maintaining the ability to control both functions separately when needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated manual actuating element is designed to perform multiple functions: it can switch the drive unit on/off, activate the braking device, and deactivate the braking device. By making one actuating element universal, the patent reduces device complexity while preserving operational safety through the ability to independently control both drive unit and braking device states.

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

2Reliability

If multiple manual actuating elements are provided for separate control of drive unit and braking device, then operational safety is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveoperational safetyVSAvoiduser convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent combines the manual actuating element for the drive unit and the manual actuating element for the braking device into a single integrated actuating element. This single element can be operated in different positions to control both the drive unit switching and the braking device activation, thereby reducing the total number of actuating elements while maintaining the ability to control both functions separately when needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated manual actuating element is designed to perform multiple functions: it can switch the drive unit on/off, activate the braking device, and deactivate the braking device. By making one actuating element universal, the patent reduces device complexity while preserving operational safety through the ability to independently control both drive unit and braking device states.

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

3Ease of operation

If drive unit can be switched on independently of braking device state, then ease of operation is improved, but reliability deteriorates due to premature wear

Engineering Contradiction:
Improveoperation flexibilityVSAvoidcomponent service life
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent incorporates a coupling between the integrated manual actuating element and the braking device such that the state of the braking device provides feedback to the actuating element. When the braking device is activated (counter-brake disc in contact with brake disc), the coupling prevents the actuating element from switching the drive unit on. This feedback mechanism ensures the drive unit cannot operate against an engaged brake, preventing premature wear while maintaining operational flexibility.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent prevents the drive unit from being switched on when the braking device is activated by designing the coupling device to create a mechanical interlock or blocking mechanism. This preliminary anti-action ensures that the drive unit cannot be activated in a state that would cause harmful friction and wear, thereby protecting component service life before the harmful condition can occur.

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 simplifies the tool's structure, enhances user convenience by reducing the number of operating elements, and extends the service life of both the braking device and drive unit by preventing unintended drive unit operation against the braking device.

Implementation Method 1

a counter-brake disc that is held non-rotatably in a housing part of the electric hand tool and is spring-loaded towards the brake disc by means of an elastic return element

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3342536B1Electric hand-held machine tool
Publication Date: 2019.08.21 METABOWERKE
  • EP3342536B1 patent drawingFigure 1

AI summary

The invention relates to an electric hand tool (10), in particular an angle grinder or the like, comprising a drive unit (12) which can be switched on and off by a user by means of a manual actuating element (50) and which has an armature shaft, a braking device (20) for braking the armature shaft after the drive unit (12) has been switched off, with a brake disc (22) which is non-rotatably connected to the armature shaft, with a counter-brake disc (24) which is held non-rotatably in a housing part (16) of the electric hand tool (10) and is spring-loaded in the direction of the brake disc (22) by means of an elastic return element (26), and with a coupling device (30) which couples the manual actuating element (50) with the counter-brake disc (24).The manual actuating element (50) includes a switching-on lock (52) which, in a first switching position of the manual actuating element (50), in which the counter brake disc (24) is in contact with the brake disc (22), prevents the drive unit (12) from being switched on, and in a second switching position of the manual actuating element (50), in which the counter brake disc (24) is released from the brake disc (22), allows the drive unit (12) to be switched on.