Pruner Blade Position Detection Using Single Sensor and Dual Magnets
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Solution Overview
Problem
Existing electric portable motorized cutting tools for pruning, such as pruning shears, face challenges with bulky and costly positional control devices using multiple sensors and magnets, which are difficult to master and install.
Innovation Solution
A portable electric motorized cutting tool with a single central magnetic sensor and at least two integral magnets on the movable blade, allowing for precise position detection without managing magnetic field crossings, making the tool less expensive, less bulky, and easier to use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnetic sensors and magnets are used for position detection, then position detection precision is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using multiple sensors to detect position, the patent inverts the approach by using a single sensor and multiple magnets. The magnets are attached to the movable blade at different positions, and a single central magnetic sensor detects their combined magnetic field to determine blade position, thereby reducing sensor count while maintaining detection capability
Solution Approach 2:
The patent combines multiple magnetic field sources (multiple magnets) into a single detection point (central magnetic sensor). The magnetic fields from multiple magnets are merged and detected by one sensor, allowing position detection with fewer components while avoiding the complexity of managing multiple independent sensor-magnet pairs
2Loss of information
If multiple magnetic sensors are used for position detection, then position information is obtained, but magnetic field crossings occur making control difficult
Solution Approach 1:
The patent introduces a central magnetic sensor as an intermediary that detects the combined magnetic field from multiple magnets. This single sensor acts as a mediator that processes the merged magnetic field information, eliminating the need to manage multiple independent magnetic field detections and their associated crossing issues
3Measurement precision
If multiple magnetic sensors and magnets are used, then position detection is achieved, but the device becomes bulky and expensive
Solution Approach 1:
The patent extracts the essential function of position detection from a multi-sensor system and implements it with a single magnetic sensor. By removing redundant sensors and using multiple magnets instead, the solution reduces the overall component count, weight, and volume while preserving the core position detection capability
Solution Approach 2:
The patent uses inexpensive magnets instead of expensive magnetic sensors. Magnets are cheaper, smaller, and easier to install than magnetic sensors, allowing the system to achieve position detection with lower cost and reduced device bulk
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 enables precise detection of the movable blade's position, facilitating easier operation and installation, with reduced costs and complexity, while allowing for accurate discrimination between open and closed positions, and precise control of the blade's movement.
Implementation Method 1
a single magnetic sensor, called central, fixed in relation to said moving blade, and at least two magnets attached to said moving blade
Data Source
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AI summary
The present invention relates to a portable electric motorized cutting tool (100), in particular a pruner, intended especially for pruning plants, comprising: - at least one movable cutting blade (102), and - at least one motor for moving said movable blade (102); characterized in that it further comprises means for detecting the position of said movable blade (102) comprising: - a single magnetic sensor (210), called central, fixedly disposed with respect to said movable blade (102), and - at least two magnets (2041,2042) attached to said movable blade (102).