Dishwasher Door Latch Mechanism for Lower Closing Force

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Solution Overview

Problem

Dishwasher door closures require high closing forces, which is a disadvantage in terms of user experience and appliance design, particularly in cost-sensitive household applications.

Innovation Solution

A closure system featuring a spring-loaded carriage with a rotary latch and locking hook, where the rotary latch interacts with the carriage to move it into a locking position using a lever and guide, reducing the closing force and enhancing assembly efficiency, while also incorporating a child safety mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a closure with locking hook and locking element is used, then the door can be securely locked, but the closing force becomes excessively high

Engineering Contradiction:
Improvelocking reliabilityVSAvoidclosing force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent introduces a dynamic latch mechanism that rotates between locked and unlocked positions, replacing the static high-force engagement. The spring-loaded carriage provides dynamic assistance during the closing process, automatically engaging the latch at the appropriate moment to reduce the force required by the user.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary latch mechanism that mediates between the door closure and the locking hook. The rotary latch acts as a mediator that can be automatically engaged by the spring-loaded carriage, transferring the locking function away from the direct door-closure interaction and thereby reducing the closing force requirement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a complex locking mechanism with multiple components is implemented, then the locking reliability improves, but the device complexity increases

Engineering Contradiction:
Improveclosure functionalityVSAvoidclosure structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into integrated components. The carriage simultaneously provides spring-loaded assistance and rotary latch actuation, while the latch mechanism integrates the locking and unlocking functions in a single rotational motion. This merging reduces the number of separate components and simplifies the overall structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring-loaded carriage serves multiple functions: it provides closing force assistance, actuates the rotary latch, and can be manually operated for unlocking. The rotary latch itself serves both as a locking mechanism and as an indicator of the locked state, demonstrating multi-functionality that reduces overall system complexity.

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

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

The solution reduces the closing force, improves functional reliability, and enhances assembly capabilities, making it suitable for cost-sensitive appliances while providing a child safety feature to prevent unintentional opening.

Implementation Method 1

The carriage is spring loaded towards the locking position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The spring is attached to a suspension on the carriage and to a suspension in the housing by appropriate hanging

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The locking hook can be brought into engagement with the locking element when it is closed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP1874173B1Dish washing machine
Publication Date: 2009.12.09 BSH HAUSGERATE GMBH
  • EP1874173B1 patent drawingFigure 1
  • EP1874173B1 patent drawingFigure 2
  • EP1874173B1 patent drawingFigure 3

AI summary

The invention relates to a closing mechanism (1) for a mobile closing element (2), especially for a door, a cover, a flap or the like on a household appliance, such as a dishwasher machine, a washing machine, a refrigerator or the like, said mechanism comprising a carriage (4) that can be displaced between a locking position and an unlocking position and is loaded by means of a spring (5) in the direction of the locking position. The carriage (4) carries a closing hook (6) that can be engaged with the closing element (2) for the closing action and/or disengaged therefrom for the opening action. A rotary latch (8) can co-operate with the closing element (2) during the closing action. As a result of this co-operation, said rotary latch (8) acts on the carriage (4) in such a way that the carriage (4) is displaced into the locking position during the closing of the closing element (2) by the force of the spring (5).