Electric Cutting Blade Positioning Without Hall Sensors

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Solution Overview

Problem

In electric cutting devices, accurately determining the current position of cutting blades is challenging due to the risk of foreign objects adhering to proximity sensors, such as Hall sensors, which can prevent precise control of the cutting operation.

Innovation Solution

The implementation of a contact detection unit that detects contact between blade members and a restriction portion, allowing the cutting blades to be moved to a preset initial position, and calculating their position based on the electric motor's operation amount, enabling accurate control of the cutting blades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a Hall sensor is provided to detect the position of the nut, then the current position of the cutting blade can be known, but foreign objects may adhere to the Hall sensor causing inaccurate detection

Engineering Contradiction:
Improveposition detection accuracyVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention extracts the detection function from the internal space where foreign objects can contaminate sensors. Instead of using a Hall sensor inside the ball screw mechanism, the patent uses a contact detection unit that detects contact between the cutting blade and the restriction portion, thereby obtaining position information without exposing sensors to contaminating environments.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary detection method. Rather than directly measuring the position of the nut with a Hall sensor, the system uses contact detection between the cutting blade and restriction portion as an intermediary event to infer position information, avoiding direct sensor exposure to foreign objects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a Hall sensor is used to detect blade position, then control of the cutting blade operation can be achieved, but the sensor may be contaminated by foreign objects entering the internal space

Engineering Contradiction:
Improveblade operation controlVSAvoidforeign object contamination
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The detection function is extracted from the vulnerable internal space to a protected detection mechanism. The contact detection unit detects blade position indirectly through contact events with the restriction portion, removing the Hall sensor from the contaminated environment while maintaining operational control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a simple contact detection mechanism that is more robust and less susceptible to contamination than precision Hall sensors. This simpler detection method, while less sophisticated, provides reliable operation control without the fragility of electronic sensors exposed to harsh environments.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4393664A1Cutting device
Publication Date: 2024.07.03 MAX CO LTD
  • EP4393664A1 patent drawingFigure 1
  • EP4393664A1 patent drawingFigure 2
  • EP4393664A1 patent drawingFigure 3

AI summary

An electric cutting device includes: a pair of cutting blades having a first blade and a second blade, the pair of cutting blades being configured to clamp and cut an object; an electric motor configured to generate a driving force necessary for operating the cutting blades; a control unit configured to control an operation of the electric motor; a first member provided with the first cutting blades; a second member provided with the second cutting blade; a restriction portion configured to come into contact with at least one of the first member and the second member to restrict an operable range of the pair of cutting blades; and a contact detection unit configured to detect that at least one of the first member and the second member comes into contact with the restriction portion.