Dishwasher Latch Mechanism That Prevents Food-Soil Switch Sticking

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Solution Overview

Problem

Traditional dishwasher latches fail to prevent food soils from accumulating in the latch mechanism, which can cause the dishwasher to operate with the door open, posing a safety hazard and risking water damage due to the switch sticking in the closed position.

Innovation Solution

A dishwasher latch design that mechanically couples a cam and switch lever to a switch actuator, using a 1-way interference coupling to ensure the switch opens when the door is pulled, and includes a self-healing feature to reset the mechanism by closing the door, preventing food soils from sticking and ensuring safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the latch mouth is designed to receive the striker, then the latch can properly seal the door to the tub, but food soils can accumulate in the latch mouth and stick the switch closed

Engineering Contradiction:
Improvelatch sealing functionVSAvoidfood soil accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the switch actuator from the vulnerable latch mouth area and couples it mechanically to the cam through the switch lever. This removes the switch actuator from direct exposure to food soils in the latch mouth, preventing accumulation while maintaining the sealing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a mechanical coupling system consisting of a cam, switch lever, and switch actuator as intermediaries between the striker engagement and the switch. This mechanical linkage transmits the door open/closed state without requiring the switch actuator to be directly accessible to food soils in the latch mouth.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the switch actuator is directly accessible in the latch mouth, then the mechanism is simple, but food soils can stick the switch closed allowing operation with door open

Engineering Contradiction:
Improvelatch mechanism simplicityVSAvoidswitch operation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a mechanical coupling system consisting of a cam, switch lever, and switch actuator as intermediaries between the striker engagement and the switch. This mechanical linkage transmits the door open/closed state without requiring the switch actuator to be directly accessible to food soils in the latch mouth.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the switch actuation function into separate components: the cam receives the striker, the switch lever transmits the motion, and the switch actuator operates the switch. This segmentation allows each component to be optimized for its specific function while reducing vulnerability to food soil contamination.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a mechanical coupling is added between the cam and switch actuator, then food soils cannot stick the switch closed, but the device complexity increases

Engineering Contradiction:
Improveswitch anti-stickingVSAvoidlatch mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cam and switch actuator into a single integrated component, eliminating the need for a separate mechanical coupling. The cam is directly formed with the switch actuator features, simplifying the mechanism while maintaining the reliability benefits of the mechanical coupling.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4442182A1Dishwasher latch resistant to sticking from food soils
Publication Date: 2024.10.09 ILLINOIS TOOL WORKS INC
  • EP4442182A1 patent drawingFigure 1~2
  • EP4442182A1 patent drawingFigure 3~4
  • EP4442182A1 patent drawingFigure 5~6

AI summary

A dishwasher latch (10) configured to be mounted to a dishwasher door and operable with a striker (20) configured to be mounted to a dishwasher tub, the dishwasher latch includes a spring mechanism (30) for drawing the door against the tub and sealing the tub in a latched position when the striker is fully engaged with the dishwasher latch. The dishwasher latch further includes a mouth (50) engageable with the striker (20) and a switch lever ((60) positioned at least partially across the mouth and in a path of the striker. A switch actuator (70) is operatively connected to a switch (80) for powering the dishwasher on or off wherein the switch actuator (70) is coupled to the switch lever (60). A cam (90) is connected between the switch lever (60) and the spring mechanism (30) wherein the cam is coupled to the switch lever when the switch lever is not in contact with the striker.