Yarn Braking Device with Stepper Motor Tension Control
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Solution Overview
Problem
Existing yarn braking devices for storage yarn feeders fail to adjust yarn tension over time, leading to quality issues and high energy consumption due to reliance on electromagnetically controlled systems and mechanically limited frustoconical braking members.
Innovation Solution
A weft-braking device combining a passive frustoconical member for static braking and an active braking system with counterposed plates, where the active braking is modulated by a linear stepper actuator or stepper motor to maintain constant yarn tension, using a tension sensor to adjust the braking action dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electromagnetic actuators are used to control braking force, then the braking action can be adjusted, but energy consumption increases significantly
Solution Approach 1:
The patent employs a stepper motor that operates periodically rather than continuously. The motor receives pulsed signals to incrementally adjust the braking force, consuming energy only when adjustment is needed rather than continuously during operation. This periodic actuation mechanism significantly reduces energy consumption while maintaining the ability to adjust braking force as yarn tension changes.
Solution Approach 2:
The system uses a tension sensor that automatically detects changes in yarn tension and triggers the stepper motor to adjust the braking force accordingly. The system serves itself by automatically compensating for tension variations without requiring continuous external control or high energy input, adjusting only when tension deviations are detected.
2Adaptability or versatility
If a frustoconical braking member is used, then braking force can be adjusted, but the system suffers from high inertia and deformability
Solution Approach 1:
The braking system is segmented into discrete adjustable components. Instead of a single deformable frustoconical member, the patent uses a structured arrangement where braking force is controlled through the engagement of discrete elements (such as adjustable plates or segmented braking surfaces) that can be incrementally positioned by the stepper motor, reducing overall system inertia while maintaining adjustability.
Solution Approach 2:
The patent transitions from a static frustoconical member to a dynamic adjustment mechanism. The braking force is controlled through active adjustment of braking plate positions or engagement depths using the stepper motor, allowing the system to adapt braking characteristics without relying on the inherent deformability of a frustoconical structure, thereby improving mechanical stability.
3Ease of operation
If electromagnetically controlled braking devices are used, then braking action can be precisely controlled, but power consumption is high
Solution Approach 1:
The stepper motor controls braking force through periodic pulsed signals rather than continuous power supply. Each pulse moves the braking mechanism to a new position, and the system maintains that position without continuous energy input, achieving precise control with minimal power consumption compared to continuously energized electromagnetic actuators.
Solution Approach 2:
The patent replaces the electromagnetic actuation system with a mechanical adjustment mechanism driven by a stepper motor. This mechanical system uses gear trains, lead screws, or rack-and-pinion mechanisms to convert rotational motion into precise linear displacement of braking components, achieving accurate braking control through mechanical advantage rather than continuous electromagnetic force.
4Device complexity
If the braking device does not adjust yarn tension, then the structure remains simple, but yarn quality deteriorates over time
Solution Approach 1:
The patent incorporates a tension sensor that continuously monitors yarn tension and provides feedback to the control system. When tension deviations are detected, the system automatically triggers the stepper motor to adjust the braking force, creating a closed-loop control system that maintains consistent yarn quality without requiring complex manual intervention or overly complicated mechanical structures.
Solution Approach 2:
The braking device performs self-adjustment based on real-time tension monitoring. The tension sensor and stepper motor work together to automatically compensate for tension variations caused by reel emptying or other operational changes, enabling the system to maintain yarn quality consistency through self-regulation without adding excessive structural complexity.
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 adjustable yarn tension over time, reducing energy consumption and mechanical limitations, ensuring consistent yarn feeding quality and efficiency.
Implementation Method 1
a spring which applies a biasing force in a direction toward the fixed braking plate
Implementation Method 2
two counterposed braking plates... adapted to brake the yarn running between them
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A first braking plate (32) is adapted to be coaxilly fixed to a delivery end of a drum (12). A second braking plate (40) is coaxially biased against the first one by elastic means (48) operatively engaged between the second braking plate (40) and an abutment (50). The yarn (Y) runs between the braking plates (36, 44), thereby receiving a braking action by friction depending on the pre-load of the elastic means. The abutment (50, 150) is operatively connected to a motor (54, 154), via rotary-to-translatory motion conversion means (58a, 64a, 150a, 151), for shifting in a direction such as the pre-load is varied. The motor (54, 154) is driven by a control unit (CU, CU') which modulates the pre-load in such a way as to maintain the tension of the yarn (Y) substantially constant on a desired level, on the basis of a signal generated by a tension sensor (70, 170) interacting with the yarn unwinding from the feeder.