Yarn Feeding Device with Closed-Loop Tension Control

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Solution Overview

Problem

Current yarn feeding technologies fail to simultaneously maintain constant tension and constant velocity, leading to defects in textile production, particularly with elastic yarns and discontinuous applications, and require synchronization with the machine, which is not always feasible.

Innovation Solution

A yarn feeding method and device that automatically switches between constant tension and constant velocity modes using a closed-loop control system with tension sensors and actuators, allowing operation without machine synchronization, and can handle both rigid and elastic yarns by adjusting feed velocity and tension dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If constant velocity yarn feeders are used to maintain constant absorbed yarn length, then manufacturing precision is improved, but device complexity increases and synchronization with the machine becomes necessary

Engineering Contradiction:

Improveabsorbed yarn lengthVSAvoidsynchronization requirement

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the controlled parameter from velocity to tension. Instead of maintaining constant velocity and calculating absorbed yarn length, the system maintains constant yarn tension using a tension sensor and actuator, allowing the yarn to be fed at variable velocity while ensuring consistent tension throughout the knitting process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical synchronization system with an electronic control system. Instead of mechanically linking the feeder velocity to the machine velocity, the system uses electronic sensors and actuators to independently control yarn tension, eliminating the need for mechanical synchronization.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If constant velocity yarn feeders are used, then absorbed yarn length remains constant, but yarn tension varies causing defects and needle breakage

Engineering Contradiction:

Improveabsorbed yarn lengthVSAvoidyarn tension stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a feedback control system where a tension sensor continuously monitors yarn tension and sends signals to an actuator that adjusts the yarn feed to maintain constant tension. This closed-loop feedback ensures both reliable tension control and consistent absorbed yarn length.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent makes the yarn feeding system dynamic by allowing velocity to vary while maintaining constant tension. The system can dynamically adjust feed velocity in response to changing machine conditions, yarn elasticity, and pattern requirements while keeping tension stable.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If constant tension yarn feeders are used to simplify operation and compensate spool tension variations, then ease of operation is improved, but absorbed yarn length varies due to friction in yarn guides

Engineering Contradiction:

Improveinterface simplificationVSAvoidabsorbed yarn length

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical friction-based tension transmission through yarn guides with an electronic control system. Instead of relying on mechanical guides that create friction and tension variations, the system uses electronic sensors and actuators to precisely control yarn tension, eliminating the friction problem while maintaining ease of operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If constant tension yarn feeders are used with elastic yarns, then ease of operation is improved, but feed velocity varies causing inconsistent absorbed yarn length

Engineering Contradiction:

Improveoperation without synchronizationVSAvoidabsorbed yarn length

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent uses feedback control to monitor and adjust yarn feed in real-time. The tension sensor provides continuous feedback that allows the system to compensate for yarn elasticity variations, ensuring consistent absorbed yarn length even when feed velocity varies due to elastic yarn properties.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP2572023B1Improved method and device for feeding a yarn or thread to a processing machine with constant tension and velocity

Publication Date: 2017.10.04 B T S R INT

Figure 1~2
Figure 3

AI summary

A method for feeding a yarn or thread to a processing machine, such as a textile machine, said method consisting of unwinding the yarn (F) from a bobbin (3), bringing it into cooperation with a rotary member (2) and then directing it to a sensor member arranged to verify its feed tension to the processing machine (9), with monitoring of the yarn feed velocity, the measured tension and measured velocity data being fed to a control unit (10) which controls the yarn feed to the machine; the tension is continuously controlled by said unit (10) in order to maintain it constant then, if this tension condition is verified, the velocity is controlled in order to render it constant, while at the same time the tension value is continuously monitored to verify whether it remains constant, this constant tension and constant velocity control of the yarn feed to the processing machine (9) being implemented without any synchronization with said machine.