Weft Tension Control via Electromechanical Torque in Circular Loom Shuttles
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Solution Overview
Problem
Existing circular loom systems face challenges in maintaining consistent weft ribbon tension, leading to fabric quality issues such as looping or constriction, and lack a reliable, mechanically simple method for monitoring weft ribbon breakages and spool exhaustion during operation.
Innovation Solution
A device for controlling weft ribbon tension on a shuttle of a circular loom, featuring a ribbon deflection device with a deflection sensor and an electromechanical load system that adjusts braking torque based on real-time tension data, integrated with a self-sufficient power supply and a weft ribbon monitor for detecting ribbon breakages and spool exhaustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If spring-loaded brake pads are used to apply friction directly on the weft spool, then weft tension can be applied, but the system becomes complex and requires experienced handling and adjustment
Solution Approach 1:
The patent replaces the mechanical spring-loaded brake pad system with an electromechanical load system. A motor (200 W) drives the weft spool through a gear mechanism, and the motor's electromagnetic torque directly controls the weft tension. This substitution eliminates the need for friction-based brake pads and spring mechanisms, reducing mechanical complexity while maintaining tension control capability.
2Force
If mechanical brake pads are used for tension control, then weft tension can be applied, but adjustment requires experience and care
Solution Approach 1:
The electromechanical system replaces manual mechanical adjustment with electronic control. The controller (PLC or microcontroller) receives feedback from tension sensors and automatically adjusts the motor torque to maintain constant weft tension. This eliminates the need for operator experience in adjusting spring tension or brake pad pressure, making the system easier to operate and maintain.
Solution Approach 2:
The system incorporates tension sensors that continuously monitor the actual weft tension and feed this information back to the controller. The controller compares the measured tension with the target value and automatically adjusts the motor torque accordingly. This closed-loop feedback mechanism ensures consistent tension control without requiring manual adjustment or operator expertise.
3Force
If friction-based brake pads are used, then weft tension can be applied, but damage to weft ribbon material may occur
Solution Approach 1:
The patent eliminates friction-based contact entirely by using the motor's electromagnetic torque to control the weft spool rotation. The motor applies force through the gear mechanism to the spool axis, not through friction on the spool circumference. This non-contact force application method completely avoids the risk of friction damage, scratching, or contamination of the weft ribbon material that occurs with brake pad contact.
4Device complexity
If simple mechanical tension control is used, then the system is simple, but constant weft tension cannot be guaranteed
Solution Approach 1:
The system uses tension sensors (load cells or strain gauges) to continuously measure the actual weft tension and feeds this data to the controller. The controller compares the measured tension with the target value and automatically adjusts the motor torque to maintain constant tension. This closed-loop feedback ensures reliable and consistent tension control, eliminating the tension variations that occur with simple mechanical systems.
Solution Approach 2:
The electromechanical system with feedback control is self-regulating. The controller automatically adjusts the motor torque based on real-time tension measurements without requiring external intervention. The system compensates for variations in spool diameter, ribbon tension requirements, and operational conditions automatically, maintaining constant tension throughout the weaving process.
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
Enables continuous monitoring and regulation of weft ribbon tension, ensuring consistent fabric quality and automatic detection of ribbon issues, thereby preventing fabric defects and optimizing the weaving process.
Implementation Method 1
a deflection sensor (5) for detecting the instantaneous position of the ribbon deflection device (3) and for generating a deflection signal (5a) as a function of the instantaneous position of the ribbon deflection device (3)
Implementation Method 2
a variable electromechanical load, through which a variable braking torque (7) is exerted on the weft ribbon spool (1)
Implementation Method 3
the weft ribbon tension occurring when the weft ribbon is pulled off causing the ribbon deflection device to be deflected from a rest position against a restoring force (4)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a device for controlling the weft band tension (FS) on a shuttle (30) of a circular loom, wherein the shuttle (30) comprises a band redirecting apparatus (3) and a weft band spool (1), from which a weft band (2) can be pulled off over the band redirecting apparatus (3). The weft band tension (FS) that occurs when the weft band is pulled off deflects the band redirecting apparatus (3) against a restoring force (FR). The control device (20) comprises: a deflection sensor (5), which detects the instantaneous position of the band redirecting apparatus (3) and generates a deflection signal (5a) as a function of the detected position, an arithmetic-logic unit (12), to which the deflection signal (5a) can be fed, and a variable electromechanical load (6, 14), which exerts a variable braking torque (7) on the weft band spool (1) according to a controlled variable (u). The arithmetic-logic unit (12) calculates the controlled variable (u) for setting the variable electromechanical load (6, 14) from the deflection signal (5a) fed to the arithmetic-logic unit so that a target value of the position of the band redirecting apparatus (3) and thus also a target value of the weft band tension (FS) are set.