Swiveling Weft Thread Tensioning for Variable Weaving Speeds
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Solution Overview
Problem
Existing weft thread tensioning devices in weaving machines struggle to provide enhanced tensioning and recuperation capabilities, particularly during varying speeds and phases of the weft insertion cycle, leading to potential loss of tension.
Innovation Solution
A method of operating a weft thread tensioning device that allows for two distinct deflection operating modes: one for high-speed weaving with constant predetermined deflection positions and another simulating a spring-like force characteristic to maintain tension during low-speed operations, using a rotary electric motor and a deflection lever with a swiveling mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single deflection operating mode is used for high-speed weaving with constant predetermined deflection positions, then productivity is improved, but the device cannot maintain optimal tensioning during low-speed operations or varying phases of the weaving cycle
Solution Approach 1:
The patent implements dynamic switching between two deflection operating modes (first mode for high-speed weaving with constant deflection positions, second mode for low-speed operations with spring-like force characteristics) to adapt the tensioning device's behavior to varying weaving conditions, resolving the contradiction between productivity and adaptability
Solution Approach 2:
The control unit changes the operational parameters of the deflection element drive by selecting different control strategies based on weaving speed and phase, switching from position-based control in high-speed mode to force-based control in low-speed mode, thereby optimizing performance across different operating conditions
2Reliability
If the deflection element is moved to maintain constant tension during low-speed operations, then tensioning capability is improved, but friction increases and energy consumption rises
Solution Approach 1:
The patent applies periodic or intermittent deflection operations rather than continuous movement, activating the deflection element only when needed to maintain tension during low-speed phases, thereby reducing energy consumption and friction while maintaining reliable tensioning when required
3Reliability
If a spring-like force characteristic is simulated during low-speed operations, then tensioning capability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical spring mechanisms with an electrically controlled deflection element drive that can simulate spring-like force characteristics through controlled movement, reducing mechanical complexity while maintaining tensioning capability through electronic control
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 method ensures consistent weft thread tensioning and recuperation, reducing friction and maintaining optimal tensioning loads across varying speeds and phases of the weaving process, enhancing operational efficiency.
Implementation Method 1
a deflection element drive (34) that comprises a rotary electric motor (36)
Implementation Method 2
By swiveling the yarn deviating arm about a swivel axis that is arranged substantially perpendicular with respect to the substantially straight yarn path, the yarn extending through the yarn-guide eyelets becomes deflected out of the substantially straight yarn path
Data Source
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AI summary
A weft thread tensioning device, comprising a weft thread path defining arrangement having two weft thread passage elements (24, 26) positioned at a distance with respect to each other for receiving a weft thread such as to extend along a straight weft thread path (P) extending between the weft thread passage elements (24, 26), a weft thread deflection element (28) positioned between the weft thread passage elements (24, 26) in the direction of the weft thread path (P), the weft thread deflection element (28) being movable such as to act on a weft thread extending across the weft thread passage elements (24, 26) for deflecting the weft thread between the weft thread passage elements (24, 26) out of the straight weft thread path (P), and a deflection element drive (34) operable for moving the weft thread deflection element (28), the deflection element drive (34) having a controller (38) associated therewith for controlling the movement of the weft thread deflection element (28) for deflecting a weft thread extending across the weft thread passage elements (24, 26), is characterized in that the deflection element drive (34) comprises a rotary electric motor (36), and that the weft thread deflection element (28) is coupled to a rotor shaft of the rotary electric motor (36) and is arranged for carrying out a swiveling movement about a swivel axis (A) that is substantially parallel to the straight weft thread path (P).