Grinder Brake Mechanism for Power Tool

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Solution Overview

Problem

Existing electric power tools face challenges in incorporating a brake device that can effectively brake the rotation of the output shaft while maintaining easy operability, particularly when the operator accidentally drops the tool, leading to unintended switch deactivation.

Innovation Solution

An electric power tool design featuring a cooperative mechanism that includes a slide member and tilted surfaces, allowing the brake device to be released by pushing the operation member toward the housing, enabling smooth sliding and reduced friction, and a biasing unit to restore the switch to the OFF position, ensuring easy operation and effective braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a brake device is added to brake the output shaft, then the stopping capability is improved, but the device complexity increases

Engineering Contradiction:
Improvestopping capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake release mechanism is merged with the existing operation member mechanism. The operation member's pushing motion is combined with the brake release function through the slide member, eliminating the need for a separate brake release actuator and reducing overall device complexity while maintaining stopping capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The operation member is given dual functionality: it serves both as the switch activation mechanism and as the brake release mechanism. By pushing the operation member, the operator simultaneously turns on the motor and releases the brake, making one component perform multiple functions and avoiding additional complexity

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

2Ease of operation

If the operation member is pushed toward the housing to turn on the switch, then the ease of operation is improved, but the brake release mechanism complexity increases

Engineering Contradiction:
Improveease of operationVSAvoidbrake release mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The slide member is pre-positioned and pre-loaded with spring force before operation. The tilted surface is pre-configured to automatically convert the pushing motion into the correct sliding direction. This preliminary arrangement eliminates the need for complex control mechanisms during operation, maintaining ease of use

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A tilted surface (inclined plane) is used to convert the linear pushing motion into the required sliding motion of the brake member. This geometric solution provides smooth, friction-reduced motion and automatic direction control without requiring complex mechanical linkages or guidance mechanisms

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The solution allows for easy operation and reliable braking of the output shaft, as the brake device can be released and reactivated smoothly, maintaining tool functionality even when dropped, by using a cooperative mechanism with tilted surfaces and a biasing unit to manage the switch state.

Implementation Method 1

allowing the brake device to be released by pushing the operation member toward the housing, enabling smooth sliding and reduced friction

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a biasing unit to restore the switch to the OFF position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2548698B1Electric power tool
Publication Date: 2016.06.15 MAKITA CORP
  • EP2548698B1 patent drawingFigure 1
  • EP2548698B1 patent drawingFigure 2
  • EP2548698B1 patent drawingFigure 3

AI summary

In a grinder (1), a motor (M) is accommodated in a housing (3) so that an output shaft (6) faces forward, a paddle switch (30) that turns on and off a drive switch (S) of the motor (M) is supported by the housing (3) so that the paddle switch (30) can be operated to move in a direction (Y) perpendicular to the output shaft (6) of the motor (M), and a brake device (60) that brakes rotation of the output shaft (6) is provided on a front side of the motor (M) in the housing (3). The grinder (1) includes a cooperative mechanism (40, 90) that releases the brake device (60) in response to a pushing operation of pushing the paddle switch (30) toward the housing (3) to turn on the drive switch (S).