Cable Feedthrough Self-Locking Thread Design

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Solution Overview

Problem

Existing cable bushings face issues with the housing connection piece becoming detached from the wall area of a device, leading to insecure installation.

Innovation Solution

The cable bushing incorporates a cap nut with a lamellar cage that engages over the housing socket, utilizing a first thread guide with a smaller pitch for the pressure ring, providing a greater self-locking effect than the second thread guide for the tensioning element, along with snap-in elements that can move radially and have centering surfaces to ensure secure mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the housing connection piece is mounted on the wall area using snap-in elements and a pressure ring, then the installation is simplified and can be quickly assembled, but the housing connection piece can become detached and the installation becomes insecure

Engineering Contradiction:
Improveease of installationVSAvoidsecurity of installation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by using two different thread pitches: a first thread guide with a smaller pitch for the pressure ring to provide strong self-locking and prevent detachment, and a second thread guide with a larger pitch for the tensioning element to allow easy cable fixation. This differential pitch design resolves the contradiction by optimizing each thread for its specific function while maintaining overall system simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The snap-in elements are designed to engage behind the opening edge of the wall area before the pressure ring is fully tightened. This preliminary engagement action provides initial mechanical support and positioning, preventing the housing connection piece from detaching during the tightening process or under subsequent cable tension, thus enhancing installation security while maintaining ease of assembly

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the first thread guide has a smaller pitch to increase self-locking effect, then the pressure ring remains securely fixed, but the thread guide becomes more complex to manufacture

Engineering Contradiction:
Improveself-locking effectVSAvoidmanufacturing complexity of thread guide
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the thread guide system into two distinct thread guides: the first thread guide with a smaller pitch dedicated to the pressure ring for secure mounting, and the second thread guide with a larger pitch for the tensioning element for cable fixation. This segmentation allows each thread guide to be optimized for its specific function, with the smaller pitch first thread guide providing enhanced self-locking where needed without requiring the entire assembly to be complex

Inventive Principle:
Principle #1Segmentation

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 enhances the self-locking mechanism, preventing the cable bushing from loosening when the clamping element is moved, ensuring a secure and stable installation by utilizing a combination of self-locking threads and radial movement of snap-in elements.

Implementation Method 1

the first thread guide has at least one thread turn with a smaller pitch than at least one thread turn of the second thread guide, that the first thread guide has a greater self-locking effect than the second thread guide provided for moving the cap nut to fix the cable

Methodology Applied
Scientific EffectSelf-locking thread mechanism: Friction

Implementation Method 2

the snap-in elements have support surfaces that can be moved radially to a central axis of the central opening and engage behind an opening edge in the wall area

Methodology Applied
Scientific EffectRadial movement mechanism: Mechanical Force

Implementation Method 3

a fixing provided on the housing connection piece with a tensioning element which can be rotated about a central axis of the central opening and which, in order to fix a cable to be guided through the cable opening, can be rotated in a second direction of rotation and thus by means of a second threaded guide is movable

Methodology Applied
Scientific EffectThreaded guide mechanism: Screw

Data Source

PatentEP1710886B1Cable feedthrough
Publication Date: 2012.12.19 LAPP ENG
  • EP1710886B1 patent drawingFigure 1
  • EP1710886B1 patent drawingFigure 2~3
  • EP1710886B1 patent drawingFigure 4

AI summary

A cable entrance has a housing nozzle (10) with central opening and an assembly device provided in the housing nozzle (10) with an assembly attachment, which can be carried through an opening (4) in a wall section (40) of an appliance. A pressure ring is provided for fixing the housing nozzle (10) rotatably in a first direction of rotation, which is opposed to a second direction of rotation of a tensioning element (16) for fixing the brought-through cable (14).