Driven Pulley Brake Mechanism for Power Cutter Kickback
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Solution Overview
Problem
Conventional power cutting machines lack an effective brake mechanism to prevent kickback, especially in handheld models, as existing brake systems are not applicable to electric motors without clutch drums and are ineffective against sudden kickback during operation.
Innovation Solution
A brake mechanism is integrated into the working device of the power cutting machine, featuring a detection mechanism that activates a tightening belt to apply a brake to the driven pulley, allowing for immediate brake application upon detecting kickback without requiring a clutch drum and without delay from intervening power transmission components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional brake mechanism is used in power cutting machines with engine motors and clutch drums, then the brake can stop the cutting blade after the motor stops, but the brake mechanism is ineffective against sudden kickback during operation and cannot be applied to electric motors without clutch drums
Solution Approach 1:
The brake mechanism is extracted from the clutch drum system and relocated to the driven pulley of the belt transmission mechanism. This allows the brake to function independently of the clutch drum, making it applicable to both engine motors with clutch drums and electric motors without clutch drums. The brake mechanism now directly brakes the driven pulley that drives the cutting blade, providing effective kickback prevention during operation.
Solution Approach 2:
The brake mechanism is designed to be universally applicable to different motor types by positioning it at the driven pulley of the belt transmission mechanism rather than at the clutch drum. This single location can serve both engine motors (with or without clutch drums) and electric motors, providing kickback prevention functionality across different power source configurations.
2Speed
If the brake mechanism is positioned at the clutch drum, then it can brake the engine motor, but it cannot effectively prevent kickback during cutting operation due to delay from intervening power transmission components
Solution Approach 1:
The brake mechanism uses the driven pulley as an intermediary point in the power transmission chain. By braking the driven pulley that directly drives the cutting blade through the belt transmission, the system achieves faster response speed and more effective kickback prevention compared to braking at the clutch drum, which is upstream in the power transmission path.
3Reliability
If no brake mechanism is provided in the working device, then the structure remains simple, but the cutting blade cannot be braked immediately during kickback events
Solution Approach 1:
The brake mechanism is designed as a self-service system that automatically activates during kickback events. The detection mechanism senses the kickback motion and automatically engages the brake on the driven pulley without requiring external control systems or complex actuation mechanisms, providing operational safety while maintaining relatively simple structure.
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 effectively prevents kickback by applying a brake to the cutting blade during operation, ensuring safety and applicability to various motor types, including electric motors without clutch drums, by directly detecting and responding to bounce events at the working device.
Implementation Method 1
a brake mechanism configured to be actuated when the cutting blade is subject to overload and apply a brake to the cutting blade
Data Source
AI summary
There is provided a power cutting machine including a main body including a motor, an arm connected to the main body at its base end and including a belt transmission mechanism configured to transmit drive power of the motor, and a working device connected to the head end of the arm and including a cutting blade configured to be rotated by power transmitted via the belt transmission mechanism. The working device includes a brake mechanism configured to be actuated when the cutting blade is subject to overload and apply a brake to the cutting blade.