Washing Machine Drum Ribs With Convex Surfaces to Prevent Laundry Sticking

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing washing machine drums with lifting ribs suffer from laundry items sticking to the inner surface and premature wear due to concave indentations and unsteady transitions, which hinder effective water distribution and gentle mixing.

Innovation Solution

The drum features lifting ribs with convex side surfaces and bead-like indentations that facilitate easy sliding of laundry, prevent sticking, and enhance water scooping, along with a smooth transition to avoid tangling and damage, optimized by a parabolic cross-section and strategically placed grooves for improved scooping and liquid distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lifting ribs with concave indentations are used to store water, then water lifting capability is improved, but laundry items stick to the drum shell and suffer deformation

Engineering Contradiction:
Improvewater storage capacityVSAvoidlaundry sticking and deformation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional concave indentation design by using convex side surfaces with bead-like protrusions. This inversion changes the geometry from water-trapping concave shapes to convex shapes that guide water flow while preventing laundry adhesion through their smooth, continuous surfaces.

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

Solution Approach 2:

The patent employs continuous curvature through convex side surfaces and bead-like protrusions, eliminating angular transitions. The convex geometry with continuous curvature allows laundry to slide smoothly off the ribs without catching on edges, while the bead structures still provide water storage and scooping functionality.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If lifting ribs are designed to lift laundry circumferentially, then water distribution is improved, but laundry items detach prematurely and stick to the drum shell

Engineering Contradiction:
Improvewater distribution efficiencyVSAvoidlaundry detachment control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies different geometric properties to different parts of the lifting rib: convex side surfaces with continuous curvature along the circumferential direction prevent premature detachment, while bead-like protrusions provide localized water storage. This local differentiation of geometric qualities allows simultaneous optimization of laundry movement and water distribution.

Inventive Principle:
Principle #3Local quality

3Shape

If angular transitions are created at the free end of lifting ribs, then structural definition is improved, but laundry items are severely deformed and rubbed

Engineering Contradiction:
Improverib structural definitionVSAvoidlaundry friction and wear
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates angular transitions by implementing continuous curvature throughout the lifting rib structure. The convex side surfaces smoothly transition into the bead-like protrusions, creating a continuously curved surface that prevents laundry from catching or rubbing against sharp edges, thereby reducing wear and deformation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 improved laundry movement, reduced wear, and effective water distribution, preventing sticking and tangling while maintaining gentle washing, even at usual washing speeds, thus enhancing the overall washing process.

Implementation Method 1

the side surface extends on the lateral surface almost at right angles in the direction of the interior of the drum and, starting therefrom, continuously flattens up to the free end of the rib... ensures that the items of laundry slide easily off the rib during the washing movement

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the bead creates a water storage unit which can lift part of the washing liquid in the drum when it is rotated. This achieves the so-called scooping effect of the rib

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2309048B1Drum for a washing machine
Publication Date: 2012.01.18 MIELE & CO KG
  • EP2309048B1 patent drawingFigure 1
  • EP2309048B1 patent drawingFigure 2
  • EP2309048B1 patent drawingFigure 3~6

AI summary

The drum (3) comprises a cylinder-like cladding (10), which is bordered by two end walls lying opposite to each other. The drum is mounted over a horizontal or inclined angle in a water container in a rotating manner. A serration (21) has a lateral surface (22) with a convex curve, where the serration extends from a lateral area (10a) running out to a free end of the serration. The lateral surface has a bead-like molding.