Dishwasher Guide Rail Stop with Directional Locking for Assembly Ease

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Solution Overview

Problem

The assembly of guide rails for dishwasher crockery baskets is complex due to the need for precise alignment and locking mechanisms, which can be cumbersome and prone to unintentional disengagement.

Innovation Solution

A directional locking device featuring a plastic molded stop that can pivot between two positions, allowing easy assembly by engaging with the guide rail in the insertion direction while preventing disassembly in the extraction direction, utilizing a hook shank and beveled surface for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stop is fixed on the guide rail to prevent disengagement, then reliability is improved, but device complexity increases due to additional locking mechanisms

Engineering Contradiction:
Improveprevention of unintentional disengagementVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stop is designed to be movable rather than fixed, allowing it to pivot between a first position (blocking the guide path) and a second position (releasing the guide path). This dynamic design enables the stop to automatically engage and disengage based on the direction of force applied, providing reliable prevention of unintentional disengagement during use while allowing intentional removal when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of requiring active engagement mechanisms to secure the guide element, the invention uses a passive movable stop that automatically blocks the guide path in the first position. The stop only moves to release the path when actively pushed in the extraction direction, inverting the conventional approach where locking requires active engagement.

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

2Ease of operation

If a movable stop is used to allow easy assembly and disassembly, then ease of operation is improved, but reliability deteriorates due to potential unintentional movement

Engineering Contradiction:
Improveassembly and disassembly easeVSAvoidstability during use
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The guide rail features an asymmetric guide path with a blocking portion that prevents the stop from moving back to the first position once it has been pushed to the second position during assembly. This asymmetric design ensures that while the stop can easily move to release the guide path during assembly, it cannot accidentally return to block the path during use, providing stability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The movable stop is pre-positioned in the first position (blocking the guide path) during manufacturing. This preliminary positioning ensures reliability during transport and storage, and allows the user to simply push the stop in the extraction direction to disengage it during assembly, without requiring complex manipulation.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a complex locking mechanism is implemented, then reliability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvelocking reliabilityVSAvoidassembly simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The stop is designed as a single integrated component that combines the blocking function and the locking function. The movable stop merges the guide element retention mechanism with the directional locking function, eliminating the need for separate locking mechanisms and simplifying the overall assembly while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The movable stop performs self-locking through its own movement and the asymmetric guide path geometry. When the guide element is inserted, the stop automatically positions itself to block the guide path, and when pulled in the extraction direction, it automatically releases. This self-service mechanism eliminates the need for external locking devices or complex assembly procedures.

Inventive Principle:
Principle #25Self-service

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

Facilitates simple and secure mounting of guide elements, ensuring the crockery basket remains in place during use and easy removal when needed, without requiring manual disengagement of the stop, thus simplifying the assembly process and enhancing user convenience.

Implementation Method 1

The stop can be displaced from a first position into a second position counter to the pull-out direction when it is acted upon and when it is fixed in the pull-out direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The side of the stop that faces the front section of the center rail can be designed as a wedge-like run-on surface

Methodology Applied
Scientific EffectMechanical force conversion: Wedge

Data Source

PatentEP2449948B1Dishwasher
Publication Date: 2021.05.19 BSH HAUSGERATE GMBH
  • EP2449948B1 patent drawingFigure 1
  • EP2449948B1 patent drawingFigure 2
  • EP2449948B1 patent drawingFigure 3

AI summary

The dishwasher has a guiding rail (1), a rinsing container, in which crockery basket is arranged for retaining washing item and a stopper (20) that is changed from a guiding path (21) into a position during its impingement against an extension direction. The stopper is fixed during its impingement in the extension direction of the crockery basket in the guide path.