Cutting Blade Brake Mechanism for Kickback Response

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Solution Overview

Problem

Conventional power cutting machines lack an effective brake mechanism to prevent kickback, especially in electric models without a clutch drum, and existing brake mechanisms are ineffective against sudden kickbacks during operation.

Innovation Solution

A brake mechanism is integrated into the working device of the power cutting machine, actuated by detecting the bounce of the working device due to kickback, applying a brake directly to the cutting blade to prevent or reduce its rotation, applicable to both engine and electric motors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a brake mechanism is provided in a clutch drum of a centrifugal clutch directly connected to the driving shaft of the engine, then the brake mechanism can stop the rotation of the cutting blade after the engine stops, but it cannot be applied to electric products not requiring clutch drums and is ineffective against kickback during motor operation

Engineering Contradiction:
Improvekickback prevention effectivenessVSAvoidmotor type compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The brake mechanism is designed to be universally applicable to different motor types (engine and electric motor) by positioning it in the working device rather than in a clutch drum specific to engine-driven machines. This allows the same brake mechanism structure to function across different power source configurations.

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

Solution Approach 2:

The brake mechanism is positioned between the belt transmission mechanism and the cutting blade, acting as an intermediary component. This placement allows it to intercept and stop the cutting blade's rotation regardless of whether the power source is an engine or electric motor, and regardless of kickback occurring during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the brake mechanism is actuated by detecting a throttle lever not operating after the engine stops, then the brake mechanism can stop the cutting blade rotation, but it is ineffective against kickback which suddenly occurs during cutting work

Engineering Contradiction:
Improvecutting blade stopping capabilityVSAvoidresponse time to kickback
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The brake mechanism incorporates a detection device that continuously monitors the working device's state during operation. When kickback occurs and the working device bounces up, the detection device immediately detects this state change and activates the brake mechanism, providing real-time feedback-based response to prevent injury.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The brake mechanism is pre-positioned in the working device and the detection device is continuously monitoring during operation. This preliminary preparation ensures that when kickback suddenly occurs, the brake mechanism can be activated immediately without delay for engine stopping or throttle lever detection.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the brake mechanism is provided in the main body, then it can stop the cutting blade, but it increases the distance for power transmission and causes delay in stopping the blade

Engineering Contradiction:
Improvecutting blade stopping capabilityVSAvoidblade stopping time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The brake mechanism is segmented from the main body and integrated directly into the working device. This segmentation allows the brake to be positioned close to the cutting blade, reducing the power transmission distance and enabling faster stopping of the blade when kickback occurs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of positioning the brake mechanism in the main body along the power transmission path, the brake is repositioned in a different spatial dimension - directly in the working device at the head end. This dimensional change reduces the distance the brake force must travel to stop the cutting blade.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 brake mechanism effectively prevents kickback by stopping or reducing the cutting blade's rotation without stopping the motor, applicable to various motor types, and reduces delays in stopping the blade due to intervening components.

Implementation Method 1

When the working device is subject to a large load... the reaction force of the load acts on the cutting blade. Then, the cutting blade provided on the head end of the power cutting machine may be recoiled from the object, which is a phenomenon called as 'kickback'.

Methodology Applied
Scientific EffectInertial force: Inertia

Implementation Method 2

a brake mechanism configured to be actuated when the cutting blade is subject to overload and apply a brake to the cutting blade

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4461447B1Power cutting machine
Publication Date: 2025.09.10 YAMABIKO CORP
  • EP4461447B1 patent drawingFigure 1
  • EP4461447B1 patent drawingFigure 2
  • EP4461447B1 patent drawingFigure 3

AI summary

A power cutting machine includes a main body (2) including a motor (10), an arm (3) connected to the main body (2) at its base end and including a belt transmission mechanism (20) configured to transmit drive power of the motor (10), and a working device connected to the head end of the arm (3) and including a cutting blade (5) configured to be rotated by power transmitted via the belt transmission mechanism (20). The working device includes a brake mechanism (30) configured to be actuated when the cutting blade (5) is subject to overload and apply a brake to the cutting blade.