Labyrinth-Sealed Link Chain for Higher Tension and Lower Fatigue
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Solution Overview
Problem
Link chains face limitations in transmitting high tension and dynamic load-carrying capacity due to constraints in material choice and dimensioning, particularly in terms of available installation space and cost, while also being prone to material fatigue and stress concentration at critical cross-sections.
Innovation Solution
The implementation of a labyrinth seal between outer and inner link plates with designed lugs and grooves, along with structural reinforcements and optimized cross-sectional areas, allows for enhanced force transmission and reduced stress concentrations, while maintaining or reducing weight and dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If material thickness and dimensioning are increased to achieve higher transmittable tension, then the link chain can transmit higher tension, but the available installation space is exceeded and costs increase
Solution Approach 1:
The patent applies local quality by creating a labyrinth seal structure with alternating lugs and grooves at specific locations on the link plates. This localized structural enhancement provides increased strength and load distribution precisely where needed (at the interface between inner and outer link plates) without requiring uniform thickening of the entire link chain components, thus maintaining compact dimensions while achieving higher transmittable tension.
Solution Approach 2:
The labyrinth seal forms a composite structural system where the interlocking lugs and grooves create a multi-layered force transmission path. This composite structure distributes stresses across multiple contact surfaces and material layers, effectively increasing the overall strength and tension-carrying capacity without proportionally increasing the volume or installation space requirements.
2Strength
If material thickness and dimensioning are increased to achieve higher transmittable tension, then the link chain can transmit higher tension, but the costs increase
Solution Approach 1:
Instead of uniformly increasing material thickness throughout the link chain (which would significantly increase material costs), the patent applies the labyrinth seal structure locally at critical stress points. This targeted approach provides the necessary strength enhancement only where load transmission is most critical, optimizing the balance between performance and manufacturing cost.
Solution Approach 2:
The labyrinth seal divides the force transmission function into multiple segmented contact points through the lug-groove-lug-groove sequence. This segmentation allows the load to be distributed across multiple smaller contact surfaces rather than requiring a single large, thick component, reducing overall material usage and manufacturing costs while maintaining high tension-carrying capacity.
3Strength
If the link chain is designed for high tension transmission, then the breaking force increases, but stress concentration occurs at critical cross-sections leading to material fatigue
Solution Approach 1:
The labyrinth seal creates localized stress distribution zones at the lug and groove contact surfaces. By concentrating the load-bearing function at these specifically designed interfaces with adequate contact area and favorable stress distribution geometry, the patent prevents stress concentration at other critical cross-sections of the link plates, thereby reducing material fatigue while maintaining high breaking force.
Solution Approach 2:
The segmented lug-groove structure distributes the total load across multiple discrete contact points along the interface between inner and outer link plates. This segmentation prevents stress concentration at any single critical cross-section by dividing the stress path into multiple segments, each experiencing reduced stress levels, thereby improving resistance to material fatigue while maintaining overall high strength.
Data Source
AI summary
A link chain comprises an inner link plate, an outer link plate, a bushing and a pin that form a chain link, and a labyrinth seal between the outer link plate and the inner link plate. The labyrinth seal comprises at least one lug having lug length and at least one groove having a groove depth, the lug length and groove depth being between 10% to 50% of an average respective link plate thickness, wherein in response to an overload of the link chain, the flow of force within the link chain is partially diverted across surfaces of the labyrinth seal formed by the at least one lug and the at least one groove.