Sealed Cable Entry Using Spacer Element and Casting Compound

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Solution Overview

Problem

Existing cable entry solutions for recessed floor lights face challenges in maintaining tightness and allowing for easy replacement, as they often rely on mechanical tension that can damage rubber elements and sheaths, and may not ensure complete sealing against moisture ingress due to capillary action between wires and insulation.

Innovation Solution

A cable entry system using a spacer element with open receiving channels on its outer surface, where insulation-free areas of individual wires are sealed with a casting compound, providing a flexible solution that can accommodate various cable diameters and numbers of cores, ensuring complete moisture protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mechanical cable gland with screw connection is used to achieve tight cable entry, then the connection can be detached and cable replaced easily, but the high radial stresses and multi-axial stress state can result in damage to rubber elements or cable sheath

Engineering Contradiction:
Improveease of cable replacementVSAvoidstrength of rubber elements and cable sheath
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The cable entry system is divided into separate functional components: a housing with opening, a cable sealing element for creating the seal, and a cable fixing element for securing the cable. This segmentation allows each component to perform its specific function without subjecting them to conflicting stress states, enabling easy cable replacement while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cable fixing element is designed to be adjustable and removable, allowing the cable entry system to adapt between different cable diameters and enabling easy cable replacement. The dynamic adjustment capability maintains optimal fixing force without creating permanent damage to rubber elements or cable sheath.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a mechanical cable gland with screw connection is used to generate radial pressure for sealing, then a seal can be created between cable jacket, rubber elements and housing, but the material slowly shifts by flowing to counteract the permanent pressure requiring readjustment

Engineering Contradiction:
Improvesealing effectivenessVSAvoidduration of seal tightness
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

A cable sealing element is introduced as an intermediary component between the cable jacket and the housing. This sealing element creates the moisture-tight seal through a pressing element that applies controlled radial pressure, while the cable fixing element secures the cable without relying on continuous high stress. This intermediary approach maintains reliable sealing over extended periods without material flow or readjustment needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the cable is cast directly in a housing to provide tight entry, then complete tightness is achieved and capillary water transport is ruled out, but the cable entry is permanently connected to housing making subsequent replacement impossible

Engineering Contradiction:
Improvetightness against moisture ingressVSAvoidease of cable replacement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The cable entry system separates the sealing function from the fixing function through distinct elements. The cable sealing element creates the moisture-tight seal within the housing opening, while the cable fixing element secures the cable in a removable manner. This segmentation achieves complete tightness against moisture ingress while allowing easy cable replacement by removing the fixing element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cable sealing element acts as an intermediary that provides the moisture barrier between the housing and the cable, while the cable fixing element provides removable mechanical retention. This dual-element approach ensures that the seal remains intact and moisture-tight even when the cable is replaced, achieving both complete tightness and ease of replacement.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If an external water stopper is used to interrupt capillaries, then water cannot enter the housing via cable, but there is an unprotected area of cable between housing and water stopper where moisture can enter if sheath is damaged

Engineering Contradiction:
Improveprotection against capillary water transportVSAvoidvulnerability to cable sheath damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cable sealing element combines multiple protective functions into a single integrated component: it seals the housing opening, protects the cable entry point, and prevents moisture ingress along the cable. This merging eliminates the unprotected area between the housing and water stopper, providing continuous protection against both capillary water transport and cable sheath damage.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cable sealing element serves as an intermediary protective barrier positioned at the housing opening, protecting the cable entry point from moisture ingress. This intermediary element prevents water from entering along the cable even if the sheath is damaged, eliminating the vulnerability present in external water stopper arrangements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system effectively seals against moisture ingress, allows for easy replacement of cables, and is adaptable to different cable and housing diameters, eliminating the need for complex assembly or special elements, thus preventing leaks and mechanical stress-related issues.

Implementation Method 1

moisture can not only be carried between the individual wires due to capillary action, but also between the Copper wire and the insulation surrounding it

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3285346B1Sealed cable entry for a component housing
Publication Date: 2020.07.08 BEGA GANTENBRINK LEUCHTEN
  • EP3285346B1 patent drawingFigure 1~2
  • EP3285346B1 patent drawingFigure 3~4
  • EP3285346B1 patent drawingFigure 5~6

AI summary

The invention relates to a cable entry for a component housing (8) with a spacer element (2) and with a cable (4) comprising several insulated individual conductors (3), wherein the individual conductors (3) are separated and guided by the spacer element (2) and an insulation-free area of ​​the individual conductors (3) is sealed at least section by a potting compound. The spacer element (2) has radially open receiving channels (20) on its outer surface for receiving the individual conductors (3), the insulation-free area of ​​each individual conductor (3) is arranged within the receiving channels (20), and at least the receiving channels (20) and the individual conductors (3) guided therein are completely sealed by the potting compound.