Dishwasher Door Lock Decoupling for Fast Reclosing

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Solution Overview

Problem

Conventional thermal actuators used in household appliances, such as dishwashers, have slow return movement speeds, preventing immediate door closure or locking after opening, which restricts appliance operation and is perceived as annoying by users.

Innovation Solution

A mechanism that kinematically decouples the door's closing or locking from the thermal actuator, allowing for immediate door closure or locking despite the actuator's slow return movement by using a device with first and second actuating elements that couple and decouple for coupling and decoupling purposes, enabling independent movement and resetting of the second actuating element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a thermal actuator is used to open the door, then the door can be opened automatically, but the return movement of the working element is slow, preventing immediate door closure or locking

Engineering Contradiction:
Improveautomatic door openingVSAvoidreturn movement speed of working element
Core Design Contradiction:
Extent of automationVSSpeed

Solution Approach 1:

The door locking system is segmented into two independent parts: the thermal actuator for opening/unlocking, and a separate closing mechanism with its own actuating element. This allows the closing action to be independent of the thermal actuator's slow return movement, enabling immediate door closure after opening.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling device with first and second actuating elements serves as an intermediary between the thermal actuator and the door closing mechanism. When the second actuating element is in the decoupled position, it allows the door to be closed independently of the thermal actuator's state, mediating between the slow thermal response and the need for immediate closing capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the door is closed immediately after opening, then appliance operation efficiency is improved, but the slow return movement of the thermal actuator prevents this

Engineering Contradiction:
Improveappliance operation efficiencyVSAvoidtime delay for door closure
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

By segmenting the door control into independent opening (thermal actuator) and closing (separate mechanism) functions, the system eliminates the time delay that would otherwise be imposed by the thermal actuator's slow return movement, enabling immediate door closure and improving operational efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device is designed to be dynamically configurable between coupled and decoupled states. When decoupled, the closing mechanism operates independently regardless of the thermal actuator's position, allowing the door to be closed immediately without waiting for the thermal actuator to return, thus eliminating time loss.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If a simple thermal actuator is used, then manufacturing cost is reduced, but additional measures are needed to enable immediate door closure

Engineering Contradiction:
Improvemanufacturing costVSAvoidcomplexity of closing mechanism
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

A relatively simple coupling device with first and second actuating elements serves as an intermediary between the inexpensive thermal actuator and the door closing mechanism. This intermediate component enables immediate door closure with minimal additional complexity, maintaining cost-effectiveness while adding the necessary functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling device serves multiple functions: it couples the thermal actuator to the door lock for automatic opening, and when decoupled, it enables independent manual closing. This multi-functionality allows a single relatively simple component to address both the cost constraint and the operational requirement.

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

Enables quick door opening and immediate closure or locking, overcoming the limitations of slow thermal actuator return movements, thus enhancing appliance operation efficiency and user experience.

Implementation Method 1

Thermal actuators usually include an expanding material (e.g. oil, wax, hard paraffin or metal), which undergoes a phase transition and thus a significant change in volume as a result of a temperature change, which leads to a movement from the initial position to the open position.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

When the expansion material cools down again, the working element, in particular the working piston, is typically pressed back into the corresponding housing of the thermal actuator by a spring and is thus moved back into its starting position.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2822442B1Household appliance
Publication Date: 2018.07.18 BSH HAUSGERATE GMBH
  • EP2822442B1 patent drawingFigure 1
  • EP2822442B1 patent drawingFigure 2
  • EP2822442B1 patent drawingFigure 3

AI summary

The present invention relates to a household appliance (1), particularly a dishwasher, comprising a door (3), a thermal actuator (6) for the opening or unlocking of the door (3) and a device (11) that is designed to uncouple a closing or locking of the door (3) from the thermal actuator (6).