Cooling and/or freezing device

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Solution Overview

Problem

Existing French Door freezers face issues with seal collisions and incomplete sealing due to sensitivity to tolerances and magnetic forces, leading to heat and moisture ingress, and are prone to door opening issues if gap dimensions or magnetic orientations are not precise.

Innovation Solution

Incorporating a door opening sensor and drive unit that moves the seal from a closed to an open end position when a door is opened, allowing unimpeded door movement and ensuring a clean seal, using pneumatically or hydraulically driven mechanisms to maintain the seal in the open position until the door is closed, thus preventing collisions and ensuring a reliable seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnets or spring elements are used to produce a defined opening position of the seal, then the seal can be positioned to prevent collision when closing and opening the door, but the arrangement becomes sensitive to tolerances and magnetic forces

Engineering Contradiction:
Improveseal positioning reliabilityVSAvoidseal positioning system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical positioning system (magnets and spring elements) with a pneumatic or hydraulic drive unit. This substitution eliminates the sensitivity to magnetic forces and spring tolerances, providing more reliable and precise seal positioning through fluid pressure control. The drive unit directly actuates the seal to the defined opening position without relying on magnetic attraction or spring elasticity.

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

Solution Approach 2:

The patent introduces a pneumatic or hydraulic drive unit to control the seal position. This uses gas or liquid pressure to actuate the seal, providing precise and reliable positioning that is not affected by magnetic forces or mechanical tolerances. The fluid pressure system enables accurate control of the seal's opening position, resolving the reliability issue with the previous magnetic/spring system.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Ease of operation

If the seal is moved away from the closed end position using a drive unit when the door is opened, then unimpeded door movement is allowed and collision is prevented, but the device complexity increases

Engineering Contradiction:
Improvedoor opening easeVSAvoidseal actuation system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by automatically moving the seal away from the closed end position as soon as the door opening is detected (before the door is fully opened). This prevents collision between the seal and the door during the opening process. The door opening sensor triggers the drive unit to retract the seal in advance, ensuring smooth door operation without interference.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a door opening sensor to detect when the door is being opened and provides feedback to the control unit. This feedback triggers the drive unit to actuate the seal to the defined opening position. The feedback mechanism ensures the seal is positioned correctly in response to door opening, preventing collision while maintaining automated control.

Inventive Principle:
Principle #23Feedback

3Reliability

If the seal remains in the closed end position when the door is opened, then the sealing function is maintained, but the door movement is impeded and collision occurs

Engineering Contradiction:
Improveseal sealing functionVSAvoiddoor opening smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements dynamics by making the seal position adaptive rather than static. The seal automatically transitions between the closed end position (when the door is closed to maintain sealing) and the defined opening position (when the door is opened to prevent collision). This dynamic positioning resolves the contradiction by adjusting the seal position according to the door state, ensuring both sealing reliability and smooth door operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses preliminary action to retract the seal before the door reaches a position where collision would occur. The door opening sensor detects the opening motion and triggers the drive unit to move the seal away from the closed end position in advance. This preliminary retraction prevents collision while maintaining the ability to restore the sealing function when the door is closed.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If the gap dimensions are selected too large or magnetic forces are too low, then the seal can move freely, but the seal may remain open and ambient air enters the cooled interior

Engineering Contradiction:
Improveseal movement freedomVSAvoidseal closure reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the magnetic force-based seal holding mechanism with a pneumatic or hydraulic drive unit. This substitution eliminates the issue of insufficient magnetic forces or inappropriate gap dimensions. The drive unit provides active control to return the seal to the closed end position, ensuring reliable closure regardless of gap variations. The fluid pressure system provides consistent force to maintain seal closure, resolving the reliability issue with the previous magnetic system.

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

Solution Approach 2:

The patent uses the door opening sensor and control unit to monitor seal position and provide feedback control. When the door is closed, the system ensures the seal is returned to the closed end position, preventing the seal from remaining open. This feedback mechanism guarantees reliable seal closure, compensating for any variations in gap dimensions or positioning, and prevents ambient air from entering the cooled interior.

Inventive Principle:
Principle #23Feedback

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

This solution prevents seal collisions, maintains a reliable seal, reduces wear, and ensures consistent sealing performance regardless of gap dimensions, enhancing the operational efficiency and reliability of the freezer by ensuring a perfect seal transition between doors.

Implementation Method 1

the device has at least one door opening sensor and at least one connected to this drive unit

Methodology Applied
Scientific EffectDoor opening sensor detection:

Implementation Method 2

the drive unit is designed so that it is activated and thus the seal moves when the door opening sensor detects the opening of a door or touching the door by a user

Methodology Applied
Scientific EffectPneumatic or hydraulic actuation:

Implementation Method 3

seals located one or more between the doors are such that the desired sealing function is reached between the doors and thus a heat input in the cooled interior between the doors is largely or completely prevented

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3390932B1Cooling and/or freezing device
Publication Date: 2021.04.14 LIEBHERR HAUSGERATE LIENZ GMBH
  • EP3390932B1 patent drawingFigure 1

AI summary

The invention relates to a cooling and/or freezing device, comprising at least one body, which encloses at least one cooled interior, and comprising at least one first (10) and one second (10') door, which doors open in opposite directions and are hinged to the body and by means of which doors the interior can be closed, wherein one or both doors have at least one seal (20, 20'), which is located in the gap between the doors in the closed state of the doors, wherein the at least one seal is in the closed end position thereof when the doors are closed, characterized in that the device has at least one door opening sensor and at least one drive unit (A, A') connected to the door opening sensor, which drive unit is designed to move at least one seal of one door away from the other door into an open end position, wherein the drive unit is also designed in such a way that the drive unit is activated when the door opening sensor senses the opening of a door or the touching of the door by a user.