Flat Knitting Machine Carriage Vibration Detection

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Solution Overview

Problem

Conventional methods for detecting abnormal vibration in flat knitting machines are insufficient at high knitting speeds, as the difference between normal and abnormal lateral vibrations becomes small, making it difficult to distinguish and detect abnormal vibrations with high sensitivity.

Innovation Solution

The implementation of a flat knitting machine with vibration detection means arranged on the carriage to detect longitudinal vibrations, which are easier to distinguish from normal knitting vibrations, and an error judgment system that adjusts the threshold value based on carriage speed to prevent false detections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vibration detection means detects lateral vibrations in the traveling direction of the carriage, then abnormal vibrations can be detected, but the difference between normal and abnormal vibrations becomes small at high knitting speeds, making detection difficult

Engineering Contradiction:
Improveabnormal vibration detection precisionVSAvoidknitting speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the detection dimension from lateral vibrations (parallel to carriage travel) to longitudinal vibrations (perpendicular to carriage travel). This dimensional change allows the vibration sensor to detect abnormal vibrations with high precision even at high knitting speeds, as the longitudinal vibration component provides better differentiation between normal and abnormal operating conditions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the threshold value is set low to detect abnormal vibrations, then detection sensitivity increases, but false detections increase due to normal vibrations at high speeds

Engineering Contradiction:
Improveabnormal vibration detection sensitivityVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a dynamic threshold adjustment mechanism that adapts the detection threshold based on the current knitting speed. As knitting speed increases, the threshold is automatically adjusted to account for increased normal vibrations, preventing false detections while maintaining high sensitivity for detecting actual abnormal vibrations. This dynamic adaptation ensures both detection sensitivity and reliability across varying operating conditions.

Inventive Principle:
Principle #15Dynamics

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 approach allows for clear detection of abnormal longitudinal vibrations, reducing false positives and negatives, and enabling reliable stopping of the knitting operation when abnormal contact occurs, even at high speeds.

Implementation Method 1

vibration detection means arranged on the carriage to detect longitudinal vibrations

Methodology Applied
Scientific EffectVibration detection: Vibration

Data Source

PatentEP2228475B1Weft knitting machine, and method for detecting abnormal vibrations in the weft knitting machine
Publication Date: 2014.10.08 SHIMA SEIKI MFG LTD
  • EP2228475B1 patent drawingFigure 1(A)~1(C)
  • EP2228475B1 patent drawingFigure 2
  • EP2228475B1 patent drawingFigure 3

AI summary

To provide a flat knitting machine capable of detecting, at high sensitivity, the abnormal vibration involved in the abnormal contact of the carriage and the knitting needle, and a method of detecting abnormal vibration. The flat knitting machine includes a needle bed 1 in which a plurality of knitting needles is arranged in parallel, and a carriage 2 for moving the knitting needles forward and backward by reciprocating on the needle bed 1. The carriage 2 includes vibration detection means (vibration sensor 4), which vibration detection means detects vibration that occurs in a direction intersecting a traveling direction of the carriage 2. Error judgment means determines presence and absence of abnormal vibration by abnormal contact of the carriage 2 and the knitting needle based on such a detection result. The abnormal vibration can be detected distinguished from the vibration involved in the normal knitting even if the traveling speed of the carriage 2 is high.