Angle Grinder Brake Pad Mechanism for Residual Rotation Stopping

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Solution Overview

Problem

Existing angle grinders face issues with residual rotational inertia of the drive shaft causing the grinding disc to continue rotating after the motor is deactivated, leading to safety concerns and inefficiencies.

Innovation Solution

The angle grinder incorporates a braking disc coupled to the drive shaft and a braking pad that moves linearly to engage and disengage from the braking disc, utilizing a biasing member and an actuator to control the braking pad's position, thereby stopping the grinding disc rotation efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the motor is deactivated after operation, then energy consumption is reduced, but the grinding disc continues to rotate due to rotational inertia causing safety concerns

Engineering Contradiction:

Improveenergy consumptionVSAvoidsafety hazard from residual rotation

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The braking system is pre-positioned and automatically activated when the motor is deactivated. The braking pad is held in a retracted position by a spring during operation, but automatically engages the braking disc when power is cut, creating a preliminary counter-action to the rotational inertia before the disc can continue rotating freely.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The rotational inertia that causes safety hazards is converted into a beneficial automatic braking mechanism. When the motor deactivates, the sudden loss of power allows the spring-loaded braking pad to engage the braking disc, transforming the harmful residual rotation into a controlled stopping process that enhances safety.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a braking system is added to stop the grinding disc, then safety is improved, but device complexity increases

Engineering Contradiction:

Improvesafety from residual rotationVSAvoidstructural complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The braking system is merged with the existing motor housing and drive shaft assembly. The braking disc is integrated onto the drive shaft, and the braking pad is positioned within the motor housing, combining multiple functions into a unified structure that minimizes additional complexity while achieving effective braking.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The braking system is self-activating through the spring mechanism that automatically engages the braking pad when the motor deactivates. The system serves itself by using the loss of motor power as the trigger for braking engagement, eliminating the need for complex control systems or additional actuators.

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If the braking pad is constantly in contact with the braking disc, then braking effectiveness is improved, but energy loss during operation increases

Engineering Contradiction:

Improvebraking effectivenessVSAvoidenergy loss during rotation

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The braking pad's position is dynamically adjusted based on operational needs. During motor operation, the spring holds the braking pad in a retracted position away from the braking disc, allowing free rotation with minimal energy loss. When the motor deactivates, the braking pad automatically moves into contact with the braking disc to provide effective braking.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The braking contact occurs periodically only when needed - specifically when the motor is deactivated. The system alternates between a non-contact state during operation (minimizing energy loss) and a contact state during braking (maximizing stopping effectiveness), creating a periodic action pattern that balances both requirements.

Inventive Principle:

Principle #19Periodic 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 solution effectively stops the grinding disc rotation quickly and safely after the motor is deactivated, eliminating the need for manual intervention and enhancing operational efficiency.

Implementation Method 1

a biasing member biasing the braking pad toward the first braking pad position

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the braking pad is in contact with the braking disc

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS20250187132A1Angle grinder

Publication Date: 2025.06.12 MILWAUKEE ELECTRIC TOOL CORP

AI summary

An angle grinder includes a motor and an output member to which a grinding disc is attachable. A drive shaft transfers torque from the motor to the output member and defines a drive axis transverse to an output axis of the output member. A braking disc is coupled to the drive shaft, and a braking pad is linearly moveable relative to the braking disc in a single direction transverse to the drive axis between a first braking pad position and a second braking pad position. A biasing member biases the braking pad toward the first braking pad position. In response to an actuator being moved from a first actuator position to a second actuator position, the braking pad is moved from the first to the second braking pad position.