Cable Feedthrough Sealing with Stepped Conical Grommet

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Solution Overview

Problem

Cable bushings struggle to ensure a high level of tightness and simplify the assembly process, particularly when dealing with cables of varying diameters and incorrect sealing element selection, leading to potential gaps and insecure sealing.

Innovation Solution

A cable bushing design featuring a frame element formed from two parts with integrated sealing elements, where the sealing elements have conical cable grommets with stepped areas, allowing for diameter-tolerant assembly by cutting the grommet to match the cable diameter, and a press fit mechanism for secure sealing without additional receptacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a sealing element with a through opening is used to pass cables, then cable penetration is enabled, but tightness and sealing reliability deteriorate due to gaps between cable and wall opening

Engineering Contradiction:
Improvecable penetrationVSAvoidsealing tightness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs a flexible sealing element made of elastomeric material that can be compressed to conform to the cable surface. The sealing element acts as a flexible membrane that adapts to the cable diameter, eliminating gaps between the cable and the wall opening while maintaining sealing integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing element's dimensions are specifically designed to be larger than the cable diameter in the uncompressed state. When compressed between the frame element and the wall opening, the sealing element changes its dimensional parameters to match the cable size precisely, ensuring tight sealing while allowing cable penetration.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a sealing element with a large passage opening is used to accommodate different cable diameters, then adaptability to different cables is improved, but sealing reliability deteriorates due to insecure sealing

Engineering Contradiction:
Improvecable diameter accommodationVSAvoidsealing security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The sealing element features a conical cable grommet with stepped areas of different diameters at its end face. This local variation in geometry allows different portions of the sealing element to accommodate different cable diameters, while each local region maintains its own sealing quality. The stepped design enables selective engagement with cables of varying sizes without compromising overall sealing reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealing element is designed to be compressible and adaptable in real-time during assembly. The elastomeric material allows the sealing element to dynamically adjust its shape and size to match the inserted cable, ensuring secure sealing regardless of the cable diameter. This dynamic adaptation eliminates the need for precise pre-matching while maintaining sealing integrity.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If additional receptacles are used to arrange sealing elements in the frame element, then positioning precision is improved, but device complexity increases

Engineering Contradiction:
Improvesealing element positioningVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sealing element is directly integrated into the frame element structure, eliminating the need for separate receptacles. The frame element's interior surface serves directly as the mounting surface for the sealing element, merging the structural support function and the positioning function into a single component. This reduces the total number of parts while maintaining precise positioning through the frame element's geometry.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If lateral insertion through slot-shaped opening is used to position cable, then assembly is simplified, but sealing reliability deteriorates due to incorrect insertion detection

Engineering Contradiction:
Improveassembly simplicityVSAvoidsealing assurance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of inserting the cable laterally through a slot-shaped opening as in conventional designs, the patent inverts the insertion direction. The cable is inserted axially through the through opening of the sealing element from the interior side, allowing direct visualization and verification of correct insertion. This inverted approach maintains assembly simplicity while ensuring sealing reliability through direct observation of the cable's position relative to the sealing element's geometry.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design ensures a high level of tightness and simplifies the assembly process by allowing for precise adaptation to cable diameters and preventing incorrect assembly, reducing the need for additional components and tools, resulting in a reliable and cost-effective sealing solution.

Implementation Method 1

one or more of the sealing elements being in an extension have a conical cable grommet molded onto the base body in the through opening, wherein the conical cable grommet has stepped areas with different diameters

Methodology Applied
Scientific EffectPress fit: Friction

Implementation Method 2

the sealing elements are arranged in the interior on a frame part and / or a further sealing element and are fixed by forming a press fit in the frame element

Methodology Applied
Scientific EffectPress fit: Friction

Data Source

PatentEP2764591B1Cable feedthrough and method for assembling a cable feedthrough
Publication Date: 2015.09.16 PHOENIX CONTACT GMBH & CO KG
  • EP2764591B1 patent drawingFigure 1~2
  • EP2764591B1 patent drawingFigure 3~4
  • EP2764591B1 patent drawingFigure 5~6

AI summary

The invention relates to a cable feedthrough comprising a frame element (1) consisting of at least two frame parts (4a, 4b), said element forming an inner chamber (2) delimited by the frame parts (4a, 4b). One or more sealing elements (3a, 3b, 3c, 3d, 3e) are located in the inner chamber (2), said elements having a base body (10) with a respective passage (15), through which a cable (9) is fed. The one or more sealing elements (3a, 3b, 3c, 3d, 3e) in the inner chamber (2) lie adjacent to a frame part (4a, 4b) and/or to another sealing element (3a, 3b, 3c, 3d, 3e) and are fixed in the frame part (1) by forming a press-fit. One or more of the sealing elements (3b, 3e) has/have a conical cable bushing (11) that is formed on the base body (10) and extends the passage (15). The conical cable bushing (11) has gradated stepped regions with diameters of different sizes.