Freezer Drawer Cam Closure for Auto-Close Without User Drag

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Solution Overview

Problem

Refrigerator bottom freezer drawers often fail to remain closed due to user error, operational vibrations, or environmental changes, leading to increased energy usage and food loss, and existing closing mechanisms are complex, expensive to maintain, and annoying to users.

Innovation Solution

A closure assembly with cooperating cam members on the drawer and refrigerator, which applies a closing force when the drawer is opened less than a predetermined distance and an opening force when opened further, using cam surfaces and a lever arm to control the drawer's position, allowing for easy access and efficient closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a closing mechanism applies closing force through the entire range of movement, then the drawer is constantly urged toward closed position, but this causes annoyance to the user when they desire the drawer to remain open

Engineering Contradiction:

Improvedrawer closure reliabilityVSAvoiduser convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The cam mechanism applies closing force only in specific local regions of the drawer's travel range. The cam surface geometry is designed to engage and apply force only when the drawer is partially open (between first and second predetermined positions), while allowing the drawer to remain stationary when fully open or fully closed, thus eliminating constant urging and user annoyance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The closing mechanism transitions from a static constant-force system to a dynamic variable-force system. The cam mechanism automatically adjusts the magnitude and presence of closing force based on the drawer's position, applying force only when needed (at partial opening positions) and releasing force when the drawer is fully open or closed, thereby improving user convenience.

Inventive Principle:

Principle #15Dynamics

2Reliability

If complex systems of springs and gears are integrated into rails, then the freezer drawer can be closed, but maintenance, repair and replacement become complicated and expensive

Engineering Contradiction:

Improvedrawer closure functionVSAvoidmechanism maintenance

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The closing mechanism is segmented into independent, modular components: a cam member attached to the drawer and a cam block attached to the refrigerator body. These separate components can be independently inspected, maintained, and replaced without affecting the entire rail system, significantly simplifying maintenance and repair operations compared to integrated spring-gear systems.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The complex spring and gear systems are extracted and replaced with a simplified cam-based mechanism. The cam and cam block components are separate from the rail system, allowing them to be removed and replaced independently, thereby reducing maintenance complexity and cost while maintaining the drawer closure function.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If no closing mechanism is used, then the drawer can remain open freely, but the drawer fails to close automatically leading to increased energy usage and food loss

Engineering Contradiction:

Improvedrawer accessibilityVSAvoidrefrigerator energy consumption

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The cam mechanism provides preliminary anti-action by automatically applying closing force when the drawer is opened only partially (between first and second predetermined positions). This prevents the drawer from remaining unintentionally open, counteracting the tendency of vibrations or user error to leave the drawer ajar, thereby reducing energy loss while maintaining easy accessibility when fully open.

Inventive Principle:

Principle #9Preliminary anti-action

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 effectively maintains the freezer drawer in the desired position, reducing energy consumption and food loss while being user-friendly and cost-effective to maintain, as it applies minimal force to open the drawer and automatically closes it when necessary.

Implementation Method 1

The cam block includes a cam surface. A cam member is configured to be disposed on the other one of the drawer and the portion of the refrigerator other than the drawer. The cam member includes a contact surface configured to contact the cam surface to urge the drawer from the open position toward the closed position.

Methodology Applied

Scientific EffectCam mechanism: Cam

Implementation Method 2

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS7753459B2Closure assembly and method

Publication Date: 2010.07.13 HAIER US APPLIANCE SOLUTIONS INC

AI summary

A closure assembly configured to urge a drawer of a refrigerator from an open position that permits access to an interior of the drawer toward a closed position that impedes access to the interior of the drawer. The closure assembly includes a cam block configured to be disposed on one of the drawer and a portion of the refrigerator other than the drawer. The cam block includes a cam surface. A cam member is configured to be disposed on the other one of the drawer and the portion of the refrigerator other than the drawer. The cam member includes a contact surface configured to contact the cam surface to urge the drawer from the open position toward the closed position.