Weft Feeder Slider Using Interference Coupling to Prevent Wear
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Solution Overview
Problem
Existing electromagnetic weft thread stopping devices in weaving machines suffer from wear-induced misalignment, dust contamination, and short useful life due to the fragility of ceramic end-pieces and the mechanical limitations of thermosetting plastic matrices, leading to premature failure and fabric defects.
Innovation Solution
The electromagnetic device employs a ceramic end-piece coupled with an aluminium intermediate element and a hyperboloid ferromagnetic core, using mechanical interference couplings and low-friction ceramic or PEEK material bushes to enhance stability and durability, along with a conical wire spring or permanent magnet for maintaining the weft thread stop position, and incorporates dust-sealing features to prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a thermosetting plastic material matrix is used to couple the ceramic end-piece and ferromagnetic core, then the slider can be made lightweight to reduce inertia, but the plastic matrix deteriorates under repeated impacts and shear stresses, leading to separation of components and premature failure
Solution Approach 1:
The patent removes the thermosetting plastic material matrix from the slider structure, extracting the problematic component that caused deterioration under repeated impacts. The ceramic end-piece and ferromagnetic core are no longer coupled through the fragile plastic matrix, eliminating the source of structural failure while maintaining the lightweight design through direct coupling of the durable components.
Solution Approach 2:
The patent employs a composite structure where the ceramic end-piece and ferromagnetic core are directly coupled without an intermediate plastic matrix. This composite design leverages the strengths of both materials - the wear resistance of ceramic and the magnetic properties of the ferromagnetic core - while avoiding the weakness of the plastic matrix that deteriorated under operational stresses.
2Device complexity
If the slider is guided by a plastic guide bush with minimum clearance, then the device structure is simple, but the guide bush undergoes progressive wear causing misalignment of the slider movement and formation of dust that contaminates the weft thread
Solution Approach 1:
The patent replaces the durable but complex self-lubricating bush material with a simpler, potentially replaceable guide bush structure. While the new bush may have shorter service life, it eliminates the progressive wear and misalignment problems of the previous design, and can be replaced more easily when worn, maintaining simple device structure while improving reliability.
Solution Approach 2:
The patent introduces a dust-sealing feature as an intermediary element between the guide bush and the external environment. This mediator prevents dust generated by guide bush wear from contaminating the weft thread, addressing the contamination issue without requiring complete elimination of the guide bush wear mechanism.
3Strength
If the ceramic end-piece is made fragile to maintain hardness and wear resistance, then it can effectively stop the weft thread, but it is susceptible to breaking under non-axial forces during weft thread stopping
Solution Approach 1:
The patent creates a composite end-piece structure combining ceramic material for hardness and wear resistance with a ferromagnetic core providing structural support and toughness. This composite design allows the ceramic outer layer to maintain its wear-resistant properties while the underlying ferromagnetic core absorbs non-axial forces and prevents catastrophic fracture, significantly improving reliability.
4Productivity
If the slider moves with high frequency to accommodate rapid weft thread insertion, then productivity is improved, but the repeated impacts and shear stresses accelerate deterioration of the plastic matrix and guide bush wear
Solution Approach 1:
The patent removes the thermosetting plastic material matrix that deteriorated under repeated impacts from high-frequency operation. By extracting this vulnerable component, the slider can withstand the high-frequency impacts of rapid weft thread insertion without the progressive deterioration that previously limited service life, maintaining productivity while extending durability.
Solution Approach 2:
The patent employs a spring-loaded mechanism that provides beforehand cushioning for the slider impacts. The spring absorbs and dissipates the impact energy from high-frequency operations before it can damage the slider components or guide bush, enabling sustained high-speed operation while protecting the structural integrity of the device.
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 configuration significantly extends the service life of the device by reducing wear, misalignment, and dust formation, while maintaining magnetic efficiency and preventing weft thread damage, allowing for predictable maintenance and improved fabric quality.
Implementation Method 1
The electromagnetic coils used in this type of device are therefore apt to provide a bistable condition of the slider
Implementation Method 2
the slider must also comprise a core of ferromagnetic material, sensitive to the magnetic fields formed by the coils
Data Source
Figure 1~3
Figure 4
AI summary
Electromagnetic device for stopping the weft thread in a weft feeder for weaving machines, of the type comprising a slider (C), apt to be moved along an alternate rectilinear path between two end-stop positions responsive to the activation of electromagnetic coils (B) housed in a case (6), consisting of a bush-shaped ferromagnetic core (3), of a cylindrical end-piece (1) for stopping the weft thread projecting from one side of said ferromagnetic core (3) and of an intermediate element (2) forming the mechanical connection between said ferromagnetic core (3) and said end-piece (1). Said intermediate element (2) is a cylindrical aluminium element which is fastened, through a mechanical coupling with interference, within the cylindrical inner cavity of said bush-shaped ferromagnetic core (3), and which further has an axial cylindrical inner cavity (2c) in which said end-piece (1) is fastened, through a mechanical coupling with interference.