Variable Draft Tension in Textile Drafting Units
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Solution Overview
Problem
Conventional textile machines experience reduced sliver adhesion during start and stop phases of the drafting system due to changes in fiber flow patterns, leading to less turbulence and lower tensile strength within the compressor.
Innovation Solution
A control and/or regulating unit is implemented to dynamically adjust the ratio of peripheral speeds between the output cylinder and take-off pulley, allowing for changes in tensioning delay during start and stop phases, ensuring the fiber flow pattern mimics normal operation, thereby maintaining consistent sliver adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the peripheral speed of the take-off pulley is kept constant during start and stop phases, then the device structure remains simple, but the sliver adhesion deteriorates due to reduced turbulence in the compressor
Solution Approach 1:
The patent applies the dynamics principle by making the peripheral speed of the take-off pulley variable rather than constant. The speed is dynamically adjusted based on the operational phase: during normal operation, the speed maintains a higher ratio to the output cylinder to generate sufficient turbulence and sliver adhesion; during start and stop phases, the speed ratio is reduced to maintain appropriate fiber flow patterns. This dynamic speed adjustment resolves the contradiction by adapting the device operation to different phases, ensuring reliable sliver adhesion without requiring permanently complex structures.
Solution Approach 2:
The patent implements parameter changes by modifying the peripheral speed parameter of the take-off pulley according to operational conditions. The control system adjusts the speed parameter dynamically: during normal operation, the peripheral speed ratio between take-off pulley and output cylinder is maintained at a higher level to create turbulence; during start and stop phases, the ratio is reduced to prevent excessive turbulence when fiber flow is already reduced. This parameter adaptation resolves the contradiction between device simplicity and sliver adhesion reliability.
2Reliability
If the peripheral speed ratio between output cylinder and take-off pulley is increased to maintain turbulence during start/stop phases, then sliver adhesion improves, but the device complexity increases due to need for dynamic speed control
Solution Approach 1:
The patent resolves this contradiction by implementing dynamic speed control of the take-off pulley based on operational phase detection. The control system monitors whether the drafting system is in normal operation or start/stop phase and adjusts the take-off pulley speed accordingly. This dynamic adaptation ensures that sliver adhesion is maintained through appropriate turbulence generation only when needed (normal operation), while avoiding unnecessary complexity during phases where turbulence requirements are different (start/stop phases).
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the peripheral speed parameter of the take-off pulley based on operational conditions. During normal operation, the speed ratio is increased to generate turbulence for good sliver adhesion; during start and stop phases, the speed ratio is reduced to match the reduced fiber flow. This conditional parameter adjustment maintains reliability while avoiding permanent device complexity.
3Speed
If the peripheral speed of the output cylinder is reduced during start and stop phases, then the fiber flow pattern changes to reduce turbulence, but sliver adhesion deteriorates
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the take-off pulley speed independently of the output cylinder speed during start and stop phases. When the output cylinder speed is reduced, the control system proportionally reduces the take-off pulley speed to maintain an appropriate speed ratio. This dynamic coordination ensures that the fiber flow pattern and turbulence level remain matched to the current operational phase, preventing sliver adhesion deterioration despite the reduced delivery speed.
Solution Approach 2:
The patent implements parameter changes by adjusting the peripheral speed parameter of the take-off pulley in response to changes in the output cylinder speed. During start and stop phases, when the output cylinder speed is reduced, the take-off pulley speed is proportionally adjusted to maintain an appropriate speed ratio. This coordinated parameter adjustment ensures that turbulence and sliver adhesion are maintained at levels appropriate for the current operational phase, resolving the contradiction between speed reduction and adhesion maintenance.
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
This adjustment ensures a fiber structure with consistent sliver adhesion comparable to normal operation, improving belt adhesion and maintaining uniformity throughout the drafting process.
Implementation Method 1
the individual sliver sections in the compressor usually assume a funnel-shaped flow pattern... so that the above-mentioned turbulence process does not occur and the sliver adhesion is less than during normal operation
Implementation Method 2
the fiber sections of the fiber web drawn with the aid of the drafting system... enter the compressor. In the compressor, they finally hit an impact surface of the same, are deflected more or less abruptly
Data Source
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AI summary
The invention relates to a textile machine, in particular a spinning preparation machine, with a drafting unit (1) for drafting a fiber assembly (2) fed to the textile machine (11), with a compressor (4) arranged downstream of the drafting unit (1) in a transport direction (T) of the fiber assembly (2) for compacting the fiber assembly (2), and with a take-off device (5) arranged downstream of the compressor (4) in said transport direction (T) for taking off the drafted fiber assembly (2), wherein the drafting unit (1) comprises at least one input cylinder (7) and one output cylinder (8) that can be driven by means of a drive (6), and wherein the take-off device (5) comprises at least one take-off disc (9) that can be driven by means of a drive (6).According to the invention, the textile machine (11) comprises means by which the ratio of the circumferential speeds of the output cylinder (8) and the take-off disc (9) (= tension delay (A)) can be changed during the operation of the drawing unit (1), at least during part of a start phase (I) and/or stop phase (III) thereof.