Nested Grommet Assembly for Multi-Size Cable Sealing
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Solution Overview
Problem
Existing grommets struggle to effectively seal a wide range of electrical cable sizes, either failing to compress adequately for smaller diameters or not accommodating larger diameters, leading to potential moisture ingress.
Innovation Solution
A nested grommet configuration comprising an inner and outer grommet, where the inner grommet can be removed to accommodate larger cable sizes, with a tapered sleeve and spring arm retainers to ensure a rain-tight and moisture-tight seal through compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single grommet with fixed through-hole diameter is used, then the grommet can seal cables within a specific diameter range, but it cannot accommodate cables with diameters outside this range
Solution Approach 1:
The patent applies nesting by placing an inner grommet inside an outer grommet. The inner grommet has a smaller through-hole diameter for smaller cables, while the outer grommet has a larger through-hole diameter for larger cables. This nested configuration allows a single grommet assembly to accommodate multiple cable size ranges, resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The grommet is segmented into multiple independent components (inner grommet and outer grommet) that can be selectively used. Each segment is optimized for specific cable diameter ranges, allowing the system to handle varying cable sizes effectively while maintaining manageable complexity through modular design.
2Reliability
If the grommet is compressed tightly to seal against smaller diameter cables, then sealing effectiveness improves, but the grommet cannot accommodate larger diameter cables
Solution Approach 1:
The nested grommet structure allows the inner grommet to provide tight compression sealing for smaller cables while the outer grommet provides a larger clearance for bigger cables. Both grommets work together to maintain sealing effectiveness across different cable sizes, resolving the contradiction between sealing reliability and cable size adaptability.
Solution Approach 2:
Different regions of the grommet assembly have different properties: the inner grommet has tighter tolerances and compression characteristics for small cables, while the outer grommet has more generous dimensions for larger cables. This local differentiation allows each component to optimize sealing for its intended cable size range.
3Adaptability or versatility
If multiple varieties of fittings with different grommet sizes are used to accommodate different cable sizes, then cable size adaptability improves, but device complexity and inventory requirements increase
Solution Approach 1:
By nesting the inner grommet within the outer grommet in a single fitting assembly, the patent consolidates multiple cable size accommodation options into one product. This eliminates the need for multiple separate fitting varieties, reducing inventory complexity while maintaining adaptability across different cable sizes.
Solution Approach 2:
The nested grommet fitting achieves multi-functionality by being capable of accommodating multiple cable size ranges through the combination of inner and outer grommets. This universal design allows a single fitting type to replace multiple specialized fittings, reducing the number of varieties needed in the product line.
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 nested grommet system provides a flexible sealing solution that accommodates varying cable sizes, ensuring a tight seal and passing rigorous rain tests, reducing the need for multiple fitting varieties.
Implementation Method 1
the tubular housing including one or more spring arm members directed towards an interior of the inner sleeve member
Implementation Method 2
Threading the fitting nut about the first threaded end causes the nested grommet to interface with the fitting nut and the sloped opening to form a seal
Data Source
AI summary
Electrical fittings utilize nested grommets that include an outer grommet portion that include a bore extending from a first circumferential end to second circumferential end, the first circumferential end having a larger surface circumference than the second circumferential end. Further, the first circumferential end has a larger surface circumference than the second circumferential end such that the outer grommet portion forms an outer surface that forms a tapered frustoconical sleeve. The nested grommets also include an inner grommet portion having a body sized to at least partially nest within the bore of the outer grommet portion.