Refrigerator Door Ajar Detection With Magnetic Repulsion Latch

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Solution Overview

Problem

Existing door ajar detection systems in refrigerators may fail to accurately detect when a door is slightly ajar, leading to false closed indications and potential loss of cooled air and increased energy consumption due to warmer air infiltration.

Innovation Solution

A door ajar detection system utilizing a first magnet on the refrigerator door and a second magnet on the opposing surface, with a latch assembly to maintain the door closed and a detection assembly coupled to the door, along with control circuitry to activate a warning signal when the door is detected as open, preventing false closed indications and ensuring the door remains closed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a door ajar detection system uses a simple closed/open detection mechanism, then the device complexity is low, but the measurement precision of door position is insufficient leading to false closed indications

Engineering Contradiction:

Improvedoor position detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is segmented into multiple independent components: a first magnet on the door, a second magnet on the opposing surface, and a separate detection assembly. This segmentation allows each component to have a specific function while maintaining overall system accuracy without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Magnets are introduced as intermediary elements between the door and the detection assembly. The magnetic field serves as a mediator to detect door position and latching status without requiring direct mechanical contact or complex sensors, thereby improving measurement precision while keeping the device relatively simple.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the door appears closed but is slightly ajar, then the visual indication suggests the door is secure, but the detection system fails to register the door as open leading to cooled air loss

Engineering Contradiction:

Improvedoor closed status reliabilityVSAvoidenergy loss from cooled air infiltration

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces traditional mechanical switch-based detection systems with a magnetic field-based detection system. This substitution allows for more sensitive and accurate detection of door position, including slightly ajar conditions that appear closed visually, thereby improving reliability and preventing energy loss from undetected open doors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection assembly provides continuous feedback about the door's latching status and position to the control system. This feedback mechanism ensures that even when the door appears closed, the system can reliably detect if it is properly latched and closed, triggering warnings or alerts to prevent energy loss from inadequate sealing.

Inventive Principle:

Principle #23Feedback

3Stability of the object's composition

If a latch assembly is used to maintain the door closed, then the door remains securely closed, but the detection system may not accurately detect slight openings

Engineering Contradiction:

Improvedoor closed position stabilityVSAvoiddoor ajar detection accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The detection system moves from a single-dimensional mechanical switch detection to a multi-dimensional magnetic field detection approach. By placing magnets on both the door and the opposing surface and using a detection assembly with multiple sensors, the system can detect door position and latching status from multiple dimensions, improving accuracy in detecting slight openings while maintaining stable closed position detection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Effectively prevents the loss of cooled air and reduces energy expenditure by ensuring the door remains closed, even when slightly ajar, through accurate detection and timely warning signals.

Implementation Method 1

a first magnet disposed on a refrigerator door and a second magnet disposed on a portion of the refrigerator opposite to the refrigerator door when the refrigerator door is in a closed position. Further, a north pole of the second magnet faces a north pole of the first magnet when the refrigerator door is in the closed position

Methodology Applied

Scientific EffectMagnetic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS10184716B1Door ajar detection system

Publication Date: 2019.01.22 WHIRLPOOL CORP

AI summary

A door ajar detection system is provided. The door ajar detection system may be incorporated in a refrigerator to provide a warning when a door is left in an open position, or to prevent a false door-closed detection. The system utilizes like magnetic poles of magnets positioned opposite to each other to push one or more doors in a refrigerator into a full open position such that a door ajar detection assembly may provide an accurate reading. A latch assembly may be provided to hold the one or more doors in a closed position against the force of the like magnetic poles.