Capacitive Tool Position Detection for Bending Devices

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Solution Overview

Problem

The accurate detection of tool position on a tool holder in bending devices is operator skill-dependent, leading to potential mistakes in tool attachment, and existing methods fail to reliably prevent erroneous tool attachments, especially in automated systems.

Innovation Solution

A tool position detection device utilizing power feeding and detection electrodes to form a capacitor circuit, which changes capacity based on the tool's position, allowing for accurate detection through voltage information extraction and arithmetic operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If operator skill-dependent manual attachment is used, then flexibility in tool selection is maintained, but attachment position accuracy deteriorates

Engineering Contradiction:
Improvemanual tool attachment flexibilityVSAvoidattachment position accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/manual attachment process with an electrical field-based detection system. Capacitive sensors detect the position of tools on the tool holder by measuring changes in capacitance values, eliminating the need for operator skill in position judgment while maintaining operational flexibility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system provides real-time feedback by detecting tool positions through capacitive sensors and comparing them against predetermined correct positions. This feedback mechanism enables automatic verification of tool attachment accuracy, allowing operators to correct misplaced tools immediately.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If automated tool attachment is implemented, then attachment position accuracy is improved, but reliability in detecting erroneous attachments deteriorates

Engineering Contradiction:
Improveattachment position accuracyVSAvoiderroneous attachment detection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors tool positions using capacitive sensors and provides feedback when deviations from correct positions are detected. By comparing actual positions against predetermined correct positions, the system reliably identifies erroneous attachments and alerts operators or automatically corrects them.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual verification processes with automated capacitive detection. The electrical field-based sensing system continuously monitors tool positions and can detect erroneous attachments with high reliability, eliminating the limitations of both manual and basic automated systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If capacitive detection system is added, then tool position detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvetool position detection accuracyVSAvoiddetection system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The capacitive detection system serves multiple functions: it detects tool presence, determines tool position, and identifies erroneous attachments. By using a single capacitive sensing mechanism for all these purposes, the system avoids the complexity of multiple separate detection systems while maintaining high detection accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system detects tool positions by measuring changes in capacitance values rather than using complex mechanical or optical measurement systems. This parameter-based approach simplifies the detection system while achieving high precision in tool position detection through electronic signal processing.

Inventive Principle:
Principle #35Parameter changes

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

Ensures accurate detection of tool position and prevents erroneous attachments by determining the correct placement of tools based on setup information, enhancing operational reliability in both manual and automated processes.

Implementation Method 1

a pair of the power feeding electrode and the power receiving electrode, which are opposite to each other, and a pair of the detection electrode and the displacement electrode, which are opposite to each other, form a capacitor circuit, a capacity of the capacitor circuit is configured to be changed in response to a position of the tool with respect to the longitudinal direction of the tool attachment unit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2868401B1Mold position detection device, bending device, mold, and method for detecting position of mounting member in relation to mounted device
Publication Date: 2018.10.24 AMADA CO LTD
  • EP2868401B1 patent drawingFigure 1
  • EP2868401B1 patent drawingFigure 2(a)~2(b)
  • EP2868401B1 patent drawingFigure 3

AI summary

On an inner wall of a tool attachment unit, a power feeding electrode (31) and a plurality of detection electrodes (32) is provided. When a tool including a power receiving electrode and a displacement electrode is attached onto the tool attachment unit, the power feeding electrode (31) and the power receiving electrode are opposed to each other, and the detection electrode (32) and the displacement electrode are opposed to each other. A pair of the power feeding electrode (31) and the power receiving electrode and a pair of the detection electrode (32) and the displacement electrode form a capacitor circuit. A capacity of the capacitor circuit is changed in response to a position of the tool with respect to a longitudinal direction of the tool attachment unit. A tool position detection unit (11) supplies an alternating current power feeding signal to the power feeding electrode (31). A voltage information extractor (330) extracts voltage information, which is changed in response to the capacity of the capacitor circuit, from the detection electrode (32). Based on the extracted voltage information, a position detection/arithmetic operation unit (111) detects to which position in the longitudinal direction of the tool attachment unit the tool is attached.