Access door

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Solution Overview

Problem

The existing double-walled plastic access doors for refrigerated cabinets are prone to cracking and breaking, particularly near the mounting sections where hinges engage, due to stress concentrations caused by external loads.

Innovation Solution

The access door design incorporates a bridge part with a primary section extending at a large angle greater than 90 degrees adjacent to the mounting section and a secondary section extending at a smaller angle, typically around 90 degrees, to distribute stress and maintain stiffness, reducing the risk of deterioration and breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bridge part extends perpendicularly from the edge part to maximize stiffness, then the access door has high stiffness and is not likely to deform, but the stress in the wall material near the mounting section increases and can result in breakage

Engineering Contradiction:
ImprovestiffnessVSAvoidstress concentration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bridge part is designed with different angular sections: a first section extending at a first angle from the edge part and a second section extending at a second angle from the first section. This creates local variations in the bridge part geometry to optimize both stiffness and stress distribution in different regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bridge part geometry is optimized to dynamically balance between stiffness and stress reduction. By adjusting the angles of different sections, the structure adapts to simultaneously provide structural rigidity while minimizing stress concentrations at critical mounting sections.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the bridge part extends at an acute angle from the edge part to reduce stress, then the stress in the wall material decreases, but the access door loses stiffness and may deform

Engineering Contradiction:
ImprovestressVSAvoidstiffness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The bridge part is divided into multiple sections with different angular orientations. The first section connects to the edge part at a first angle, while the second section extends at a second angle from the first section, allowing each segment to perform its specific function of either stress reduction or stiffness provision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the bridge part have different geometric properties tailored to their specific functions. The first section is optimized for stress distribution while the second section maintains structural stiffness, creating local quality variations throughout the bridge part.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3194870B1Access door
Publication Date: 2020.02.12 POLYPLASTIC GROUP
  • EP3194870B1 patent drawingFigure 1A~1B
  • EP3194870B1 patent drawingFigure 2A~2D

AI summary

An access door (1) for application in a refrigerated cabinet comprises a multi-walled plastic door construction of a sheet-like first wall (10) and a plane-parallel second wall (20). The walls each comprise all around an edge part (12,22) with which the walls are connected. One of the two walls has a central part (21) which lies offset relative to the edge part (22) and wherein the central part and the edge part are connected by a bridge part (23a,23b). The door construction has a mounting section (25) for mounting an adjusting member thereon in order to enable adjustment of the door construction in the refrigerated cabinet between a position closing the refrigerated cabinet and an open position. The bridge part (23a,23b) comprises a primary bridge part section (23a) which is adjacent to the mounting section (25) and extends at a first angle from the edge part and a secondary bridge part section (23b) which extends at a second angle from the edge part, wherein the second angle is smaller than the first angle.