Rotatable Mower Handle Control for Folded-Position Motor Lockout
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Solution Overview
Problem
Existing gardening tools like mowers pose safety risks due to high-speed functional accessories, which can be dangerous if the operator inadvertently starts the tool while the handle is in a folded or rotated position, bringing the user too close to the main body.
Innovation Solution
A gardening tool with a rotatable handle connected to the main body, featuring a control system that prevents the motor from being operated when the handle is not in a secure position, utilizing multiple control devices to ensure safety by locking the motor unless all risk items are in designated states, and incorporating a brake system to stop the functional accessory upon motor shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the handle is made longer to keep the operator away from the main body, then safety is improved, but the handle becomes more difficult to store and maneuver
Solution Approach 1:
The handle is designed to be rotatable relative to the main body, allowing it to dynamically change position between an extended operating position and a retracted storage position. This dynamic configuration enables the handle to provide safety distance during operation while being compact for storage and maneuverability when not in use.
Solution Approach 2:
The handle assembly is segmented into multiple parts that can rotate relative to each other, specifically the handle rotating relative to the main body. This segmentation allows the handle to be positioned at different angles and distances from the main body, providing both safety during operation and ease of storage when retracted.
2Ease of operation
If the handle is allowed to fold or rotate for convenient storage, then ease of operation is improved, but the risk of accidental motor startup increases when the user is too close to the main body
Solution Approach 1:
The control system is configured to detect the handle position before allowing motor operation. The system preliminarily checks whether the handle is in the correct extended position before enabling the motor to start, preventing accidental startup when the handle is folded or rotated during storage.
Solution Approach 2:
The control system continuously monitors the handle position and provides feedback to the motor control circuit. When the handle is detected to be in an incorrect position (folded or rotated), the system automatically prevents motor operation. When the handle is properly extended, the system enables motor operation, creating a closed-loop safety mechanism.
3Reliability
If multiple control devices are added to prevent accidental operation, then safety is improved, but the device complexity increases
Solution Approach 1:
The control system serves multiple functions: it monitors handle position, prevents accidental motor startup, and controls motor operation. By integrating these functions into a single control circuit that responds to handle position, the system achieves enhanced safety without proportionally increasing complexity.
Data Source
AI summary
A gardening tool, such as a mower, has a main body having an accessory, such as a mowing blade, and a motor for driving the accessory. A handle is rotatably connected to the main body. At least one operation assembly is associated with the handle for being operated by a user to control the motor when the handle is located in a predetermined position. A control system prevents the motor from being controlled by the operation assembly and halts the motor when the handle is located out of the predetermined position.