Multi-Membrane Grommet Structure for Cable Sealing and Strain Relief
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Solution Overview
Problem
Existing grommets struggle to provide both effective sealing and strain relief for elongated objects with varying diameters due to complex structures that often result in inadequate elasticity and poor sealing quality.
Innovation Solution
A grommet design featuring an outer frame element with at least two membranes spaced apart, each with perforations that touch the frame element, and zones of varying elasticity, allowing for accommodation of objects with different diameters while ensuring good sealing and strain relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple membranes are arranged in series to accommodate cables of different diameters, then adaptability is improved, but device complexity and length increase
Solution Approach 1:
The grommet is divided into a frame element and multiple membranes arranged in series, with each membrane having a perforation. This segmentation allows each component to perform its specific function while collectively accommodating cables of different diameters through the coordinated action of multiple elements.
Solution Approach 2:
The membranes are designed with different local properties - they are more elastic than the frame element and have specific thickness ratios (membrane thickness between 0.5-2mm, frame element thickness 2-5mm). This local quality differentiation enables the membranes to deform and adapt to different cable diameters while the stiffer frame provides structural support.
2Adaptability or versatility
If membranes are designed to surround the entire cable with high elasticity, then adaptability is improved, but sealing quality deteriorates due to lateral tilting and protrusions
Solution Approach 1:
The membrane is designed with non-uniform thickness - the peripheral region (within 5mm of the perforation edge) is thinner (0.5-1.5mm) for better sealing, while the central region is thicker (1-2mm) for adequate elasticity. This local quality variation allows the membrane to maintain both adaptability and sealing quality.
Solution Approach 2:
The membrane structure is segmented into different functional zones: a peripheral sealing zone with thinner material that contacts the cable outer jacket, and a central support zone with thicker material that provides elasticity. This segmentation resolves the contradiction between needing elasticity for adaptation and maintaining sealing quality.
3Reliability
If membrane thickness is increased to ensure tightness, then sealing quality is improved, but strain relief capability deteriorates due to reduced elasticity
Solution Approach 1:
The membrane exhibits local quality variation in thickness - thinner at the periphery (0.5-1.5mm) for sealing and tighter fit, thicker at the center (1-2mm) for elasticity and strain relief. This gradient thickness distribution simultaneously achieves both tightness and elasticity requirements.
Solution Approach 2:
The membrane is designed to be dynamic rather than static - it can deform elastically to accommodate cables of different diameters and then maintain a tight seal. The specific thickness ratio enables the membrane to dynamically adjust its shape while maintaining sealing pressure on the cable outer jacket.
4Device complexity
If the grommet structure is made compact, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The membrane is integrally formed with the frame element as a single piece, eliminating the need for separate assembly operations. The membrane is directly connected to the frame element at its edges, ensuring precise positioning without requiring additional manufacturing precision for separate component alignment.
Solution Approach 2:
The membrane is pre-formed with its specific thickness gradient and perforation geometry during the injection molding process. This preliminary action of creating the precise thickness distribution and perforation shape during manufacturing reduces the need for post-processing and ensures consistent positioning accuracy.
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 design maximizes membrane surface area and ensures reliable positioning of the object, providing excellent sealing and strain relief for elongated objects with varying diameters in a compact and efficient manner.
Implementation Method 1
The invention relates to a grommet made of a material which is at least partially elastic for receiving at least one elongated object
Data Source
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AI summary
The invention relates to a grommet consisting of a material which is elastic at least in some sections for accommodating at least one elongate object for strain relief and sealing, said grommet having an outer frame element which can be folded open along a slot and has at least two membranes which are spaced apart in the longitudinal direction of the elongate object to be accommodated and each have, flush with each other, an equally sized hole for accommodating the elongate object. The invention is characterised in that the respective holes of the at least two membranes contact the material of the frame element on the side of the slot.