Accumulation Yarn Feeder with Feedback-Controlled Weft Braking
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Solution Overview
Problem
Existing weft braking devices controlled by feedback, such as those with frustum-shaped and comb-type brakes, are limited in applying high yarn feed tensions required for certain textile processes, and are either complex and expensive or lack manual adjustability.
Innovation Solution
An accumulation yarn feeder with a dual braking system, comprising a passive frustum-shaped braking device and an active comb-type braking device controlled by feedback, where the active device uses a step motor and non-reversible transmission means for high braking forces, and allows manual adjustment through a wheel mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a frustum-shaped braking device controlled by feedback is used, then the braking force is sufficient for low-tension applications, but it cannot apply high braking forces required for certain textile processes
Solution Approach 1:
The patent combines a passive frustum-shaped braking device with an active comb-type braking device controlled by feedback into a single integrated system. The passive device provides baseline braking force while the active device supplies additional controllable force through a step motor, enabling the system to handle high-tension applications up to 100-200 cN that neither device could achieve alone.
2Force
If a comb-type braking device controlled by feedback is used, then high braking forces can be applied, but the system becomes complex and expensive
Solution Approach 1:
The braking system is segmented into two independent functional components: a passive frustum-shaped brake that provides constant baseline braking force, and an active comb-type brake controlled by a step motor that provides variable additional braking force. This segmentation allows each component to be optimized for its specific function while keeping the overall system manageable and cost-effective.
Solution Approach 2:
The passive frustum-shaped braking device operates autonomously without requiring external control signals or power supply, providing continuous baseline braking force through its elastic deformation against the drum. This self-service characteristic reduces system complexity by eliminating the need for control electronics and power systems for the passive component.
3Force
If a comb-type braking device controlled by feedback is used, then high braking forces can be applied, but manual adjustability is lost
Solution Approach 1:
The patent implements a dual-mode braking system where the passive frustum-shaped device can be manually adjusted by rotating the drum to change its elastic deformation and thus its braking force, while the active comb-type device provides automated feedback control. This dynamic configuration allows operators to switch between manual adjustment for setup and automated control for operation.
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
The system achieves higher yarn feed tensions efficiently and economically, with the ability to manually adjust braking forces, acting as an auxiliary passive brake when needed, while maintaining simplicity and cost-effectiveness.
Implementation Method 1
an active weft braking device (36) controlled by feedback by a control unit (CU)
Implementation Method 2
The yarn in output from the feeder slides while pressed between the drum and the hollow frustum-shaped element, thus receiving a braking action by friction
Implementation Method 3
a passive weft braking device (18) of the conventional type, which is adapted to apply a preset uncontrolled braking action to the yarn that unwinds from the drum (12)
Data Source
Figure 1
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Figure 3
AI summary
A drum (12) supporting a yarn (Y) wound upon itself, which is adapted to be unwound upon request from a downstream textile machine. A passive weft braking device (18) and an active weft braking device (36) brake the yarn (Y). A tension sensor (66) downstream of the active weft braking device (36) measures the tension of the yarn (Y) and sends a corresponding signal to a control unit (CU), which drives by feedback the active weft braking device (36). The latter comprises at least one first weft braking lamina (44a, 44b), which is pushed against an abutment (46a, 46b) by motor means (48) connected to the control unit (CU), with the interposition of transmission means (40a, 40b, 42a, 42b, 52). The yarn (Y) slides between the weft braking lamina (44a, 44b) and the abutment (46a, 46b).