Front-Loading Drum Seam Depression for High-Speed Stability

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Solution Overview

Problem

Front loading laundry machines experience increased resistance and potential seam damage at high rotation speeds due to uneven seam heights and centrifugal forces, which can lead to seam unfixing during drum rotation.

Innovation Solution

A depression is formed along the seam between the cylindrical and rear walls of the drum, bulging inwardly, to center tension distribution and counteract centrifugal forces, with the depression's shape and placement optimizing tension management and seam stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the drum rotates at high speeds (over 1200 rev/min), then the laundry treatment effectiveness is improved, but the seam region experiences increased damage risk due to centrifugal forces

Engineering Contradiction:
Improvedrum rotation speedVSAvoidseam stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention introduces a localized depression structure at specific positions along the seam, creating non-uniform local geometry that modifies tension distribution. This local structural modification allows the seam to better withstand centrifugal forces during high-speed rotation without compromising overall drum performance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The depression structures are pre-formed along the seam during drum manufacturing, before the drum enters service. This preliminary structural preparation ensures that the tension-distributing feature is already in place to counteract centrifugal forces when high-speed rotation begins, preventing seam damage rather than reacting to it

Inventive Principle:
Principle #10Preliminary action

2Reliability

If an impression region is added to increase resistance during rotation, then seam damage is prevented, but the outer diameter of the drum becomes non-uniform

Engineering Contradiction:
Improveseam protectionVSAvoiddrum outer diameter uniformity
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

Instead of creating a continuous impression region that would distort the overall drum shape, the invention uses discrete, localized depressions positioned specifically along the seam. These localized features provide the necessary tension distribution and seam protection while maintaining the uniform outer diameter of the drum body, as the depressions are confined to the seam region only

Inventive Principle:
Principle #3Local quality

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 depression along the seam effectively manages tensions, preventing seam unfixing and maintaining drum stability even at high rotation speeds, ensuring safe operation of the laundry machine.

Implementation Method 1

a factor which can lead to the unfixing of the seam by means of the outward centrifugal force is overcome by means of the depression which is in opposite direction

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2673411B1Drum type front loading laundry treating machine
Publication Date: 2014.12.24 BSH HAUSGERATE GMBH
  • EP2673411B1 patent drawingFigure 1
  • EP2673411B1 patent drawingFigure 2~4
  • EP2673411B1 patent drawingFigure 5

AI summary

The present invention relates to a front loading laundry machine with a drum comprising a cylindrical wall (10), a rear wall (20) secured to said cylindrical wall (20) and a seam (30) between the edge (12) of the cylindrical wall (10) and a rim (22) of the rear wall (20), whereby at least one depression (35) is provided at a distance between a distal end (33) and proximal end (31) of the seam (30).