Dishwasher Roller-Guided Carrier Design to Prevent Rack Twisting

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Solution Overview

Problem

Household dishwashers experience twisting and high frictional forces when pulling out or pushing in the C-rail, leading to scratching and grinding noises, which detract from user-friendliness, especially when handling heavy items.

Innovation Solution

A household dishwasher design featuring a support element with a C-shaped profile and four rollers arranged at the corners of a trapezoid or parallelogram, where the first and second rollers guide the upper tread, and the third and fourth rollers guide the lower tread, preventing twisting and reducing frictional forces by ensuring all moving parts align in the same direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a C-shaped rail is used to support the dishware holder, then the structural simplicity and ease of manufacture are improved, but twisting occurs and high frictional forces are generated during movement

Engineering Contradiction:
Improveease of manufactureVSAvoidease of operation
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The support element is divided into multiple rollers (at least three rollers) that are distributed along the C-shaped rail. Each roller independently contacts the rail and supports the dishware holder, segmenting the contact points to prevent twisting while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rollers are designed to rotate freely along the C-shaped rail, transforming the static friction problem into a dynamic rolling motion. This allows the dishware holder to move smoothly without generating high frictional forces, while the rollers adapt dynamically to the rail's geometry.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If rollers are mounted on the C-shaped rail to enable movement, then the ease of operation is improved, but twisting of the support element occurs leading to scratching and grinding noises

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Different sections of the C-shaped rail are assigned specific functions by positioning rollers at optimized locations. The rollers are placed at specific intervals along the rail to provide localized support points that prevent twisting, ensuring reliable operation without scratching or grinding noises.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The support system transitions from a single-plane contact to a three-dimensional roller distribution along the C-shaped rail. By positioning rollers at different locations and orientations, the system prevents twisting moments while maintaining smooth linear movement, eliminating scratching and grinding noises.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 prevents twisting of the support element, reduces frictional forces, and enhances user-friendliness by allowing smooth and stable movement of the washware holder, even when handling heavy loads, thus improving the mechanical stability and ease of use.

Implementation Method 1

a first roller (17) and a second roller (18) and a third roller (19) and a fourth roller (20), which are each arranged at one of the corners of a trapezoid or a parallelogram, wherein the first roller (17) and the second roller (18) guide the upper tread (22) and the third roller (19) and the fourth roller (20) guide the lower tread (23)

Methodology Applied
Scientific EffectRolling: Roller

Data Source

PatentEP3761844B1Domestic dishwasher
Publication Date: 2024.10.02 BSH HAUSGERATE GMBH
  • EP3761844B1 patent drawingFigure 1
  • EP3761844B1 patent drawingFigure 2~3
  • EP3761844B1 patent drawingFigure 4~5

AI summary

The invention relates to a domestic dishwasher (1), comprising a washing container (2), a first roller (17, 18, 19, 20) and a second roller (17, 18, 19, 20), a roller holder (16), on which the first roller (17, 18, 19, 20) and the second roller (17, 18, 19, 20) are rotatably mounted and which is fastened to the washing container (2), and a carrier element (21) for carrying a washing items receptacle (12, 13, 14), which carrier element is mounted for movement relative to the roller holder (16) by means of the first roller (17, 18, 19, 20) and the second roller (17, 18, 19, 20) in such a way that the washing items receptacle (12, 13, 14) can be moved between a position in which the washing items receptacle is pushed into the washing container (2) and a position in which the washing items receptacle is pulled out of the washing container (2). The carrier element (21) has an upper running surface (22) and a lower running surface (23). The first roller (17, 18, 19, 20) is spaced apart from the upper running surface (22) downward and runs along the lower running surface (23). The second roller (17, 18, 19, 20) is spaced apart from the lower running surface (23) upward and runs along the upper running surface (22).