Dishwasher Door Lock Piston With Child-Safe Limiting Lever

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Solution Overview

Problem

Household dishwashers often lack effective mechanisms to prevent unintentional opening of the door, particularly by children, which can lead to safety concerns.

Innovation Solution

A door lock system with a movable locking piston and a limiting device that blocks or releases the piston's movement in specific positions, ensuring the door can only be opened when the limiting device is in its release position, providing a child safety feature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a door lock with a movable locking piston is provided, then the door can be securely locked in the closed position, but the door can still be unintentionally opened by children or other persons applying sufficient tensile force

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoidunintentional door opening
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The door locking system is segmented into two independent functional components: a door lock with a movable locking piston for securing the door, and a limiting device with blocking and releasing positions for preventing unintentional opening. This segmentation allows each component to perform its specific function effectively without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The limiting device is configured to block the movement of the locking piston in its blocking position before any opening force is applied to the door. This preliminary blocking action prevents children or other persons from accidentally opening the door by pulling on the handle, as the locking piston cannot move to release the door until the limiting device is manually switched to its releasing position.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If a limiting device is added to block piston movement, then protection against unintentional opening is achieved, but the device complexity increases

Engineering Contradiction:
Improveunintentional door opening preventionVSAvoiddoor lock system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The limiting device is integrated with the existing door lock system, sharing common structural elements such as the housing and the locking piston. The limiting device utilizes the same mounting points and spatial arrangement as the door lock, merging two safety functions into a single unified assembly rather than adding a completely separate mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The limiting device serves multiple functions: it blocks the locking piston movement to prevent unintentional door opening, it provides a manual switching mechanism for authorized opening, and it integrates with the existing door lock structure. This multi-functionality reduces the need for additional separate components and simplifies the overall system design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2289387B1Dishwasher, in particular domestic dishwasher
Publication Date: 2013.11.27 BSH HAUSGERATE GMBH
  • EP2289387B1 patent drawingFigure 1
  • EP2289387B1 patent drawingFigure 2~3
  • EP2289387B1 patent drawingFigure 4

AI summary

The dishwasher has a washing tank comprising an access opening closable by a door. A door lock is provided at a front edge region of the washing tank or at the door and provided with a movable closing piston. A limiting device (6) is formed as a lever and retained at the front edge region of the washing tank or at a housing (5) of the door lock, where the limiting device is made of plastic material or metal. The limiting device blocks movement of the closing piston in a position (10) and releases the movement of the closing piston in another position (11).