Weft feeder with adjustable-diameter drum for weaving looms, comprising an electromagnet unit controlling the weft thread release equipped with a quick-release device to adjust and fix its working position
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Solution Overview
Problem
Existing weft feeders with adjustable-diameter drums face issues with precise and repeatable adjustment of the ELM unit position due to inherent play in the screw/pawl assembly, leading to incorrect parallelism and centering of the stop pin, requiring repetitive adjustments.
Innovation Solution
A weft feeder with an ELM unit fixed by a pair of fixed and mobile guides with inclined flat surfaces, coupled via a quick-release locking/unlocking device using an eccentric lever, ensuring precise and repeatable positioning without tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ELM unit position is adjusted using the screw/pawl assembly, then the ELM unit can be fixed in a desired position, but inherent play in the assembly prevents precise and repeatable positioning
Solution Approach 1:
The adjustment mechanism is segmented into distinct functional elements: the ELM unit body, the pawl component, the tie rod, and the eccentric lever. This segmentation allows each component to perform its specific function independently, eliminating the play inherent in integrated screw/pawl assemblies while maintaining adjustability.
Solution Approach 2:
The mechanism transitions from a static fixed position to a dynamically adjustable position through the eccentric lever. The lever allows the operator to easily move the ELM unit along the guides and lock it at any desired position, providing both ease of adjustment and positional stability once locked.
2Adaptability or versatility
If the ELM unit position is adjusted frequently to chase the drum position, then adaptability is improved, but time is lost due to repetitive adjustments
Solution Approach 1:
The ELM unit position is preliminarily adjusted to match the drum position before operation begins. The quick-adjust mechanism allows this preliminary positioning to be done accurately and quickly, eliminating the need for repetitive adjustments during operation and reducing time loss.
Solution Approach 2:
The system incorporates feedback through the optical unit that monitors the weft thread winding on the drum. This feedback allows the ELM unit position to be adjusted based on actual operational conditions, ensuring optimal positioning without excessive manual intervention.
3Ease of operation
If the screw/pawl assembly is loosened for adjustment, then the ELM unit can be repositioned, but the unit ends up in a different position from the working position
Solution Approach 1:
The traditional screw-based mechanical system is replaced with an eccentric lever mechanism. This substitution eliminates the play and positioning errors inherent in screw threads while maintaining ease of operation. The eccentric lever provides a clear mechanical advantage for quick adjustment without compromising position repeatability.
Solution Approach 2:
The eccentric lever introduces asymmetry into the locking mechanism. The offset center of rotation creates a natural mechanical advantage that allows easy loosening and tightening while maintaining precise positioning. The asymmetric geometry ensures that once locked, the position is repeatably accurate.
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 allows for quick, tool-free adjustment and maintains stable, precise positioning of the ELM unit, ensuring constant parallelism and centering of the stop pin, enhancing operational efficiency.
Implementation Method 1
an electromagnet unit E which controls the release of the weft thread
Data Source
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AI summary
Weft feeder for weaving looms with thread coil separation comprising a winding group (W) to wind a weft thread onto a weft feeder drum (D), and an electromagnet unit (E) to control the movement of a stop pin (P) which prevents the weft thread from being released from said drum (D), wherein said electromagnet unit (E) is movable in a radial direction with respect to an axis of the weft feeder drum (D), along a pair of guide means (1, 2) provided in the base body (C) of said weft feeder and in said electromagnet unit (E), respectively, which consist of a pair of fixed guides (1) and a pair of mobile guides (2) symmetrically arranged with respect to an axial plane of the weft feeder passing therebetween and parallel thereto, each pair of guides having flat contact surfaces (1a, 2a) symmetrically inclined with respect to said axial plane of the weft feeder. A single locking/unlocking means (3, 4) having an axis parallel to the drum (D) axis stably fixes said electromagnet unit (E) in a predefined position and includes a pawl (3) housed in an undercut recess, provided between said pair of fixed guides (1) or in the weft feeder base body (C), and a tie-rod (4) connected to said pawl (3).