False Twist Device Yarn Deflection Edges
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Solution Overview
Problem
Existing false twist devices for open-end spinning machines often damage the yarn due to sharp edges, limiting the achievable false twist and affecting spinning stability, especially when trying to introduce false twist without causing excessive stress on the yarn.
Innovation Solution
A false twist device with multiple edges arranged in a tubular body, where each edge deflects the yarn at an angle, creating a spatial helical deflection that increases the false twist without requiring sharp edges, thus minimizing yarn damage and enhancing spinning stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sharp false twist edges are used to generate greater false twist, then the false twist generation is improved, but the yarn surface is damaged
Solution Approach 1:
The false twist edges are designed with rounded profiles instead of sharp edges. The curvature of the edges reduces stress concentration and prevents yarn surface damage while still effectively generating false twist through the deflection of yarn at these rounded edges.
Solution Approach 2:
The invention changes the geometric parameters of the false twist edges by optimizing the inclination angle (30-60 degrees relative to yarn take-off direction) and rounding the profiles. These parameter modifications allow sufficient false twist generation without the harmful effects of sharp edges.
2Productivity
If multiple false twist edges are arranged to increase false twist, then the false twist generation is improved, but the device complexity increases
Solution Approach 1:
Multiple false twist edges are integrated into a single tubular body structure, combining multiple functional elements into one unified component. This reduces assembly complexity while maintaining the ability to generate sufficient false twist through multiple edges arranged in sequence.
Solution Approach 2:
The false twist device is segmented into multiple edges arranged one behind the other in the yarn take-off direction, with each edge contributing to the overall false twist effect. This segmentation allows distributed false twist generation while keeping each individual edge simple in design.
3Productivity
If the yarn wrap angle is increased to prevent yarn lifting off the edge, then the false twist effect is improved, but the yarn stress increases
Solution Approach 1:
The rounded profile of the false twist edges allows the yarn to wrap around them smoothly, increasing the wrap angle and improving false twist effect while distributing stress more evenly along the yarn contact path, preventing stress concentration that would occur with sharp edges.
Data Source
Figure 1
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AI summary
A false twist device (17) for an open-end spinning device (1) for introducing a false twist into a yarn (7) has a substantially tubular body (20) and several false twist edges (19) arranged one behind the other in the yarn take-off direction (G) and inclined at an angle (α) relative to the yarn take-off direction (G) within the body (20). The several false twist edges (19) project into the interior of the tubular body (20) such that the yarn (7) is deflected at each of the false twist edges (19). Furthermore, the several false twist edges (19) are arranged circumferentially offset within the body (20) such that the yarn (7) simultaneously experiences a spatial deflection relative to its regular yarn take-off direction (G) due to the successive deflections at the several false twist edges (19).An open-end spinning unit (1) of a rotor spinning machine (2) with a yarn take-off nozzle (16) has a false twist device (17) located downstream of the yarn take-off nozzle (16) in the yarn take-off direction (G). In a method for introducing a false twist into yarn (7) produced in an open-end spinning unit (1) of a rotor spinning machine (2), the yarn (7) is taken off via a yarn take-off nozzle (16) and drawn over false twist edges (19) arranged in a false twist device (17) located downstream of the yarn take-off nozzle (16), thereby imparting a false twist to the yarn (7). The yarn (7) is subjected to a spatial deflection relative to its regular yarn take-off direction (G) by the false twist edges (19), thereby imparting an additional false twist to the yarn (7).