Dishwasher Door Lock With Switchable Child-Safety Latching Force

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Solution Overview

Problem

Existing door locks for dishwashers lack an adjustable locking force mechanism, making it difficult to implement a child safety feature that can easily switch between low and high locking force settings.

Innovation Solution

A door lock design featuring a pivoting element with preloaded torsion springs and a rolling or sliding element that engages with a latching slope, where the locking force can be adjusted by modifying the position of an operating lever and transmission element to either single or dual spring engagement, thereby altering the required opening force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed spring element is used in the door lock, then the structure is simple, but the locking force cannot be adjusted between low and high values

Engineering Contradiction:
Improveadjustability of locking forceVSAvoidcomplexity of spring mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The door lock transitions from a fixed locking mechanism to a dynamic one where the spring element can be switched between two positions (first and second positions) along the guide. This allows the locking force to be adjusted between low and high values by changing the engagement position of the spring element with the latching slope, resolving the contradiction between adaptability and complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of spring engagement position to adjust the locking force. By moving the spring element between two defined positions along the guide, the effective spring constant and locking force are modified. This parameter change enables adjustable locking force without requiring multiple different spring elements, thus managing device complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the locking force is increased for child safety, then safety is improved, but the door becomes difficult to open for normal operation

Engineering Contradiction:
Improvechild safetyVSAvoidease of door opening
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The door lock allows dynamic switching between two operational modes: a high-locking-force mode for child safety and a low-locking-force mode for normal operation. The operating element enables the user to switch between these modes by moving the spring element between its first and second positions, thus resolving the contradiction between reliability and ease of operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring element is divided into two distinct engagement positions along the guide, creating two separate operational states. The first position provides high locking force for child safety, while the second position provides low locking force for easy opening. This segmentation allows the system to offer both safety and ease of operation at different times.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a form-fit locking device is used instead of force-fit, then positive locking is achieved, but the simplicity of operation is reduced

Engineering Contradiction:
Improvepositive lockingVSAvoidsimplicity of opening
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The latching element is segmented into a latching slope and a horizontal latching surface. The rolling element transitions from engaging the latching slope (force-fit) to engaging the horizontal surface (form-fit), providing positive locking while maintaining operational simplicity through the rolling motion along the defined path.

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

Enables a simple and effective child safety mechanism by allowing the locking force to be easily adjusted between low and high settings, enhancing safety while maintaining secure closure during dishwasher operation.

Implementation Method 1

two preloaded, mirror-symmetrical torsion springs (15, 16) are arranged on the roller holder (13) around the pivot axis (14)

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

a roll (26) is freely rotatably mounted on the roll axis (25)... the roller (26) runs along the starting slope (6.1) and presses the roller holder (13) clockwise upwards

Methodology Applied
Scientific EffectRolling friction: Friction

Data Source

PatentEP2415384B1Door lock for domestic appliances and dishwasher with door lock
Publication Date: 2013.05.15 MIELE & CO KG
  • EP2415384B1 patent drawingFigure 1~2
  • EP2415384B1 patent drawingFigure 3~5

AI summary

The machine i.e. dishwasher (1), has a force-locking latching mechanism i.e. door lock (3), placed on a washing chamber (10), where the latching mechanism is arranged to hold an appliance door (2) in a closed position and to release the door in response to a pulling force. A door opening system includes a push-open unit (5) that is arranged to automatically open the door to an ajar position, where the push-open unit includes a motor-driven push-type opening bar (504). A magnetic coupler is arranged to retain the door on the push-type opening bar.