Terry Weaving Backrest Assembly Tension Control
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Solution Overview
Problem
In terry weaving machines, the tension of pile warp threads increases substantially when the woven fabric moves, leading to loops and requiring low tension for terry fabrics but high tension for flat fabrics, which existing systems fail to manage effectively.
Innovation Solution
A backrest assembly with a tension roller supported by a rotatable support beam and loaded by a bellow spring, coupled via a linkage system, maintains constant warp tension by using a pressure regulator system to adjust air pressure within the bellow spring, allowing for easy adjustment and varying tension as needed for different fabric types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tension roller is resiliently mounted to move with the woven fabric, then the fabric can be displaced without pulling back pile warp threads, but the tension of the pile warp threads increases substantially during the movement
Solution Approach 1:
A linkage system with a coupling lever acts as an intermediary between the bellow spring and the tension roller. The coupling lever rotates about the support beam axis and translates the linear motion of the bellow spring into rotational motion of the support beam, which then moves the tension roller. This intermediary mechanism allows the tension roller to follow the fabric movement while the bellow spring maintains constant tension through its pressure-regulated compression force.
Solution Approach 2:
A bellow spring (pneumatic spring) is used to apply a constant compression force to the tension roller. The bellow spring is filled with gas at a regulated pressure, which provides a substantially constant force during the movement of the tension roller. This pneumatic element allows the tension roller to move with the fabric while maintaining constant pile warp thread tension, resolving the contradiction between ease of operation and force stability.
2Adaptability or versatility
If low tension is applied to pile warp threads, then loops can be formed for terry fabric, but high tension is required for flat fabric weaving between terry fabrics
Solution Approach 1:
The tension of the pile warp threads is controlled by changing the pressure parameter of the gas inside the bellow spring. By regulating the gas pressure in the bellow spring, the compression force applied to the tension roller changes, which directly adjusts the tension on the pile warp threads. This allows switching between low tension for terry fabric loop formation and high tension for flat fabric weaving, providing adaptability through a single adjustable parameter.
3Force
If the distance between the bellow spring force application position and the support beam axis is larger, then the leverage effect increases, but the support beam rotation and tension roller movement become excessive
Solution Approach 1:
The support beam is designed to rotate dynamically about its axis rather than being fixed. The coupling lever is attached to the support beam to rotate with it, allowing the system to adapt its geometry during operation. As the tension roller moves, the support beam rotates to maintain an optimal distance between the bellow spring force application position and the support beam axis, preventing excessive leverage while ensuring sufficient movement range. This dynamic adjustment maintains position stability while providing the necessary leverage effect.
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 solution ensures that the tension roller moves with the woven fabric without significant variations in warp tension, maintaining consistent tension for terry and flat fabric weaving, enhancing the weaving process by preventing loop formation and allowing for easy adjustment of tension.
Implementation Method 1
the tension roller is loaded by at least one bellow spring
Implementation Method 2
a distance between the force application position of the at least one bellow spring on the coupling lever and the support beam axis is shorter than or equal to a distance between an axis of the tension roller and the support beam axis
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A backrest assembly for pile warp threads (13) in a terry weaving machine (1), wherein a tension roller (16) is arranged to guide the pile warp threads (13), wherein the support beam (33) is mounted so as to be rotatable to-and-fro about a support beam axis (34), wherein the tension roller (16) is supported in parallel to the support beam (33) by two or more support elements (51), which support elements (51) are mounted fixed in position to the support beam (33), and wherein the tension roller (16) is loaded by at least one bellow spring (52, 152). A backrest assembly having a support beam (33) provided at its shell surface with a positioning element (65) extending in parallel to the support beam axis (34) and support elements (51) aligned to each other by means of the positioning element (65). A terry weaving machine with such a backrest assembly (3). Use of a bellow spring (52, 152) in a backrest assembly (3) for pile warp threads (13) in a terry weaving machine (1).