Electric Scissor Foreign Matter Detection via Motor Torque
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Solution Overview
Problem
Existing electric scissors used for pruning face issues with erroneous cutting of wires and nicking of blades due to the presence of hard wires, leading to blade breakage and reduced cutting efficiency, and existing solutions involving dedicated sensors and circuits are costly, increase device dimensions, and suffer from maintenance difficulties and erroneous detections.
Innovation Solution
A foreign matter detecting mechanism that uses angle information and torque changes of the motor to differentiate between cutting targets like trees and wires, without the need for dedicated sensors or circuits, by setting thresholds based on blade closure angles and torque information, and includes modes to prevent erroneous detection and blade nicking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated conductive sensor and dedicated circuit are provided in the blade section to detect metal wires, then the erroneous cutting of wires can be prevented, but the manufacturing cost increases
Solution Approach 1:
The blade section itself serves as the detection element by utilizing its own electrical conductivity properties. When the blade contacts a conductive object like a wire, the electrical circuit through the blade detects the contact, eliminating the need for separate dedicated sensors and circuits. This self-service approach maintains reliability while significantly reducing manufacturing cost and complexity.
2Reliability
If a dedicated conductive sensor and dedicated circuit are provided in the blade section, then the erroneous cutting of wires can be prevented, but the device dimension increases
Solution Approach 1:
The blade section utilizes its inherent electrical properties as the detection mechanism, eliminating the need for additional sensor components and circuitry that would increase the blade section's volume. The blade's own electrical conductivity serves as the detection medium, maintaining compact dimensions while preventing wire cutting errors.
3Reliability
If a dedicated conductive sensor and dedicated circuit are provided in the blade section, then the erroneous cutting of wires can be prevented, but the cutting ability degrades due to the thickened blade section
Solution Approach 1:
The blade section maintains its original thin profile and cutting geometry by using its own electrical conductivity for detection purposes. No additional thickening or structural modifications are required, as the electrical detection function is integrated into the blade's existing structure, preserving both reliability and cutting ability.
4Reliability
If a dedicated conductive sensor and dedicated circuit are provided in the blade section, then the erroneous cutting of wires can be prevented, but the maintenance of the blade section becomes difficult
Solution Approach 1:
The blade section's electrical detection function is inherently integrated into its structure, eliminating separate sensor components and circuits that would require specialized maintenance. The blade itself serves as both the cutting tool and the detection element, simplifying maintenance procedures and improving ease of repair while maintaining reliability.
5Reliability
If a dedicated conductive sensor is provided in the blade section, then the metal wire detection can be performed, but erroneous detection occurs when sap or moisture adheres to the blade section
Solution Approach 1:
The blade section uses its own electrical circuit for detection, and the control unit analyzes the electrical characteristics during the cutting operation. By monitoring the electrical circuit behavior specifically during blade closure and cutting action, the system can distinguish between legitimate wire contacts and false contacts caused by sap or moisture, maintaining both reliability and measurement precision.
Data Source
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AI summary
A foreign matter detecting mechanism of electric scissors detects pinching of a foreign matter in the electric scissors. The electric scissors have blade sections which are interlocked with a rotation of a motor. The mechanism includes a foreign matter detecting unit. The foreign matter detecting unit detects that the blade sections pinch the foreign matter. The foreign matter detecting unit detects the foreign matter based on torque information of the motor.