Sewing Machine Triangulation Sensor for Fabric Thickness Detection

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Solution Overview

Problem

Existing sewing machines lack effective methods for accurately detecting and adapting to varying sewing material thickness, leading to inefficient and noisy operation.

Innovation Solution

The integration of a triangulation sensor that enables precise material thickness detection, allowing for automatic adjustments of sewing parameters and processes, including needle positioning, foot lift height, and material transport, through signal connections with the needle bar drive, foot lift drive, and control device, ensuring accurate and quiet operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a triangulation sensor is used for material thickness detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvematerial thickness detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical thickness measurement methods with an optical triangulation sensor system. The sensor uses a light source and detector arranged in a triangulation configuration to optically measure material thickness, eliminating the need for mechanical contact probes or complex mechanical adjustment mechanisms.

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

Solution Approach 2:

The patent introduces a light source as an intermediary element to enable non-contact thickness measurement. The light source projects light onto the material surface, and the reflected light is detected by the sensor, creating an optical intermediary path that allows precise measurement without direct physical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If automatic thickness-based adjustments are implemented, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvesewing operation efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the triangulation sensor continuously measures material thickness and automatically adjusts presser foot pressure and needle position in real-time. This closed-loop feedback enables the sewing machine to adapt to varying material conditions without manual intervention, improving productivity while managing complexity through automated control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The sewing machine system performs self-adjustment based on sensor input. The control system automatically modifies operating parameters (presser foot pressure, needle position, feed rate) according to the measured material thickness, allowing the machine to serve itself without requiring constant operator adjustment or complex manual control mechanisms.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the triangulation sensor is integrated into the sewing machine structure, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improveautomatic thickness adaptationVSAvoidmachine structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The triangulation sensor system is designed to serve multiple functions: it measures material thickness, triggers automatic presser foot pressure adjustment, controls needle positioning, and can potentially monitor other sewing parameters. This multi-functionality consolidates what could be separate systems into a single integrated sensor platform, improving ease of operation while managing overall system complexity.

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

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

This solution allows for precise material thickness measurement, enabling faster and quieter sewing operations, automatic adaptation to changing material thickness, and enhanced error detection and quality control, resulting in improved sewing machine performance and efficiency.

Implementation Method 1

The invention recognizes that a triangulation sensor makes it possible to measure the thickness of a fabric very precisely. The distance ratio A/B of at most 1/10 leads to a sufficiently accurate triangulation measurement and thus to a sufficiently accurate distance determination.

Methodology Applied
Scientific EffectOptical triangulation: Parallax

Data Source

PatentEP4060106B1Sewing machine
Publication Date: 2024.04.17 DURKOPP ADLER GMBH
  • EP4060106B1 patent drawingFigure 1
  • EP4060106B1 patent drawingFigure 2
  • EP4060106B1 patent drawingFigure 3

AI summary

A sewing machine (1) has stitch-forming tools that interact in a stitch-forming area (12) to create a seam in a fabric (11). A fabric feed unit (2) serves to transport the fabric (11) along a sewing direction (17). A thickness sensor (21) serves to detect the thickness of the fabric (11) in a detection area (20) that is located upstream of the stitch-forming area (12) in the sewing direction (17). The thickness sensor (21) is designed as a triangulation sensor with a light source for measuring light (23) and a detector for the measuring light (23). A source center of the light source, a center (Z) of the detection area (20), and a center of the detector define exactly one triangulation plane (xz) of the triangulation sensor (21). The measuring light detector is designed to detect the measuring light (23) reflected and/or scattered by the fabric (11) within the detection area (20). This results in a sewing machine with improved fabric thickness detection.A retrofit kit for such a sewing machine includes a corresponding thickness sensor and a mounting body for mounting the thickness sensor on a user-side head section of an arm of the sewing machine.