Automatic door for dishwasher with multi-position sensing

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Solution Overview

Problem

Residential dishwashers require significant user effort to properly compress the door gasket for sealing during washing and venting during drying, and existing automatic door opening systems are complex and cumbersome.

Innovation Solution

A dishwasher door mechanism using a multipoint position-sensing electric actuator with a DC motor and rack-and-pinion system allows for bidirectional motion, enabling automatic door opening and closing with reduced user effort, incorporating an encoder for precise position control and user input sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a vigorous pressing or lever-action latch is used to compress the door gasket, then the sealing force is sufficient, but the operation becomes cumbersome and requires adjustment over time

Engineering Contradiction:
Improvegasket compression forceVSAvoiddoor closing operation
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The door closing system uses a spring mechanism that automatically compresses the gasket when the door is closed, eliminating the need for user effort. The spring stores potential energy during door closure and releases it to maintain continuous gasket compression, making the system self-regulating and adjustment-free.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical lever-action latches with a simpler spring-based compression system. This substitution eliminates the need for mechanical advantage calculations and multiple adjustment points, reducing operational complexity while maintaining sufficient sealing force.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If electrically actuated shutters are used for venting during drying, then noise transmission is reduced, but the device complexity increases

Engineering Contradiction:
Improvenoise transmissionVSAvoidventing mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the venting function from the door structure itself and implements it through a separate, dedicated shutter mechanism. This allows the main door to remain simple while the venting system provides controlled airflow through electrically actuated shutters that can be independently controlled to minimize noise transmission during drying cycles.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If an automatic door opening device is used to improve venting, then drying efficiency is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvedrying efficiencyVSAvoiddoor opening system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The automatic door opening device operates periodically during the drying cycle, opening the door at predetermined intervals to enhance venting. This periodic action improves drying efficiency by allowing moisture escape without requiring the door to remain continuously open, thereby maintaining a balance between productivity improvement and device complexity.

Inventive Principle:
Principle #19Periodic action

4Adaptability or versatility

If multi-position sensing is implemented in the actuator, then versatility and control precision are improved, but the device complexity increases

Engineering Contradiction:
Improveactuator position controlVSAvoidsensing system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuator incorporates multi-position sensing capability that allows it to serve multiple functions: precise door positioning during closing, venting control, and detection of door obstruction. This universal sensing system replaces what would otherwise require separate sensors for each function, improving versatility while minimizing the increase in device 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 simplifies door operation, reduces user effort in sealing and venting, and provides improved drying efficiency by allowing controlled door positioning and sensing, ensuring proper engagement and reducing the risk of damage to utensils.

Implementation Method 1

a DC motor (50) communicating through at least one pinion gear with the gear rack to move the plunger (40) along the axis in a first and second direction with different polarities of electrical current applied to the DC motor (50)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

the encoder provides at least one encoding track (58) extending along the elongate section to interact with at least one stationary sensor

Methodology Applied
Scientific EffectOptical encoding: Optical Fibre

Data Source

PatentEP3457906B1Automatic door for dishwasher with multi-position sensing
Publication Date: 2023.08.02 ILLINOIS TOOL WORKS INC
  • EP3457906B1 patent drawingFigure 1~2
  • EP3457906B1 patent drawingFigure 3
  • EP3457906B1 patent drawingFigure 4A~5

AI summary

A dishwasher (10) provides a motorized latch element extending to open the dishwasher door (18) for venting according to sense positions. A robust rack and pinion mechanism driven by a DC motor (50) provides flexible positioning of the door for different applications while ensuring sufficient force to compress the dishwasher gasket for sealing.