Cable Bushing With Clamping Projections For Strain Relief

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Solution Overview

Problem

Existing bushings for electrical lines in vehicles fail to provide long-term strain relief due to loosening of sealing elements caused by temperature fluctuations and vibrations, which compromises moisture-tight sealing and secure cable fixation.

Innovation Solution

A bushing design featuring an extension and clamping body with projections that securely locks the cable in place, ensuring stable positioning under tensile loads and independent of temperature fluctuations and vibrations, allowing for easy installation and removal, and accommodating cables of different diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing elements are used to ensure moisture-tight sealing, then moisture protection is improved, but strain relief deteriorates due to loosening during operation

Engineering Contradiction:
Improvemoisture-tight sealingVSAvoidstrain relief
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The adapter is divided into functionally independent parts: a sealing element for moisture protection and a clamping body with projections for strain relief. This segmentation allows each component to perform its specific function without interfering with the other, resolving the contradiction between maintaining sealing integrity and providing stable strain relief.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element and clamping body are combined into a single adapter assembly that performs both sealing and strain relief functions simultaneously. The clamping body with its projections engages the cable while the sealing element maintains moisture barrier, achieving both reliability and stability through integration.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If sealing elements are used to ensure moisture-tight sealing, then moisture protection is improved, but long-term stability deteriorates due to loosening from temperature fluctuations and vibrations

Engineering Contradiction:
Improvemoisture-tight sealingVSAvoidlong-term stability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

By separating the sealing function from the strain relief function into distinct components (sealing element vs. clamping body with projections), the design ensures that the strain relief mechanism is not affected by thermal expansion or vibration-induced loosening that would compromise the sealing element alone over time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element can be replaced independently if it degrades over time, while the clamping body with projections remains as a durable, long-lasting component that maintains strain relief. This allows the short-living sealing element to be maintained without replacing the entire adapter.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If the adapter structure is extended to provide strain relief, then strain relief is improved, but device complexity increases

Engineering Contradiction:
Improvestrain reliefVSAvoidadapter structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The extension is localized to specific regions of the adapter where strain relief is needed, rather than redesigning the entire adapter structure. The clamping body with projections is added only at the cable engagement point, maintaining simplicity in other areas while providing enhanced strain relief where required.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The clamping body with projections is nested within or integrated into the existing adapter structure, with the extension fitting into the overall adapter geometry. This nesting approach adds strain relief functionality without significantly increasing the external dimensions or overall complexity of the adapter assembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP2008875B1Feedthrough for an electric cable
Publication Date: 2009.08.26 NEXANS SA
  • EP2008875B1 patent drawingFigure 1
  • EP2008875B1 patent drawingFigure 2
  • EP2008875B1 patent drawingFigure 3~4

AI summary

The bushing has an adapter (A) made of insulating material and fixed at a wall. A flange (4) is screwed at dot and dash indicated areas in the wall in a position, in which a connecting piece (5) passes via a hole. The piece is moisture-proof. The adapter includes a borehole (8) for leading an electrical line (3), where the borehole extends via an extension. Through-holes (13) made in the extension pass from an outer surface (12) to the borehole. A clamping body (15) includes projections (17) which are engaged in the through-holes in a mounting position for clamping arrangement at the line.