Thread Feeder Brake Step Counting for Position Recovery

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Solution Overview

Problem

Existing thread feeder brake systems in textile machines cannot reliably open and immediately return to their original position without complex position detection, leading to issues like defects in manufactured articles and machine stoppages during tension regulation.

Innovation Solution

A method that counts the motor steps during brake opening and stores this count, allowing the motor to reverse the exact number of steps to return the brake to its original position, utilizing motor turning speed to detect the limit stop, thus avoiding the need for expensive position sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the brake is opened electronically by rapidly moving the brake slide to the limit stop, then complete opening is achieved, but the motor becomes stalled and the original position information is lost

Engineering Contradiction:
Improvebrake openingVSAvoidoriginal position information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system performs preliminary action by counting the motor steps during the opening phase before reaching the limit stop. This step counting is done in advance so that when the brake needs to be reclosed, the stored step count information is already available to guide the motor back to the exact original position without needing complex sensors.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the brake slide is returned to a standard predefined initial position, then the system maintains simplicity, but defects may form and machine stoppages may occur during the transition interval

Engineering Contradiction:
Improvecontrol systemVSAvoidthread tension stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses feedback by continuously monitoring the motor's turning speed or current draw to detect when the slide has reached the end of its opening travel and abutted against the limit stop. This feedback mechanism allows the system to know when to stop counting steps and store the totalized count, enabling precise return to the original position without requiring complex position sensors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by using the motor's own operational characteristics (turning speed, current draw) to detect the limit stop condition and determine the original position. This eliminates the need for external position sensors while maintaining the ability to return to the exact original position, thus improving reliability without increasing device complexity.

Inventive Principle:
Principle #25Self-service

3Device complexity

If a step motor is used for relative position control, then the system is inexpensive and reliable, but the brake cannot be returned to its exact original position after opening

Engineering Contradiction:
Improvecontrol systemVSAvoidbrake position
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by counting the motor steps during the opening phase before reaching the limit stop. This step counting is done in advance so that when the brake needs to be reclosed, the stored step count information is already available to guide the motor back to the exact original position without needing complex sensors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by continuously monitoring the motor's turning speed or current draw to detect when the slide has reached the end of its opening travel and abutted against the limit stop. This feedback mechanism allows the system to know when to stop counting steps and store the totalized count, enabling precise return to the original position without requiring complex position sensors.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2586896B1A method and a device for opening and subsequently closing a weft brake in a thread feeder
Publication Date: 2019.05.22 L G L ELECTRONICS SPA
  • EP2586896B1 patent drawingFigure 1~4
  • EP2586896B1 patent drawingFigure 2~3
  • EP2586896B1 patent drawing

AI summary

According to the method of the invention, the step motor (14) of the brake (20, 23, 24, 26) of the thread feeder, upon opening command (to), is driven in the direction of opening the brake, while counting the steps made by the motor until the brake is stopped by abutment against a travel stop (22), and storing the step count reached at the time of blockage (step_to_open). upon a subsequent closing command (t3), the step motor is driven in a direction of closing the brake by a number of steps equal to the stored count.