Refrigerator
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Solution Overview
Problem
Existing refrigeration devices with inner containers face issues of shelf instability due to production-related draft angles, leading to wedge-shaped gaps and potential damage from uneven support, requiring thick plastic blanks for stability and risking shelf misalignment and tilting.
Innovation Solution
A refrigeration device with a guide device on the inner container wall that compensates for the draft angle, providing a support surface and guide mechanism to stabilize and center the shelf, reducing lateral play and preventing tilting, while allowing for thinner plastic usage and improved manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner container wall is drawn with a draft angle for manufacturing, then the inner container can be easily produced and removed from molds, but a wedge-shaped gap is created between the shelf and the inner container wall causing shelf instability and lateral play
Solution Approach 1:
The inner container wall is segmented into two functional zones: a draft angle region for easy manufacturing and removal from molds, and a guide device region with a guide surface that provides precise shelf guidance. This segmentation allows the wall to simultaneously enable easy production while maintaining shelf stability through the dedicated guide surface that compensates for the wedge-shaped gap created by the draft angle.
Solution Approach 2:
The guide surface is created as a localized feature on the inner container wall with specific geometric properties (parallel to the shelf's bottom surface) that differ from the rest of the wall's draft angle. This local quality change ensures that only the critical shelf support area has the precision needed for stable shelf mounting, while the rest of the container maintains the draft angle for manufacturing ease.
2Strength
If thick plastic blanks are used to ensure adequate wall thickness and stability in the bulge areas, then the inner container gains structural strength, but the stretching during vacuum drawing increases and production complexity rises
Solution Approach 1:
The guide surface is pre-formed as an integral part of the inner container wall during the vacuum drawing process, rather than requiring subsequent machining or assembly steps. This preliminary action ensures that the guide surface is already in place to provide precise shelf guidance, eliminating the need for additional production steps and reducing overall manufacturing complexity while maintaining structural strength.
Solution Approach 2:
The guide surface is formed with a curved or spherical geometry that naturally distributes stresses during vacuum drawing, reducing localized stretching and the need for excessively thick plastic blanks. The curved geometry allows the material to flow more evenly during forming, maintaining adequate wall thickness and strength while reducing production complexity.
3Reliability
If the shelf is not centered on the support surface, then the bulges are stressed at their outer tips and may break or become damaged, but centering the shelf requires precise positioning mechanisms that increase device complexity
Solution Approach 1:
The guide surface is designed to automatically center the shelf on the support surface through its geometric configuration, eliminating the need for external positioning mechanisms. As the shelf is placed on the guide surface, the geometry naturally guides it into the correct centered position, ensuring that the bulges are not stressed at their outer tips and preventing damage without increasing device complexity.
Solution Approach 2:
The guide surface acts as an intermediary element between the shelf and the support surface, mediating the positioning process. It provides a controlled interface that guides the shelf into the correct position, preventing direct contact between the shelf and the potentially damaging outer tips of the bulges, thereby protecting the structure without requiring complex positioning mechanisms.
4Manufacturing precision
If the guide device compensates for the draft angle of the inner container wall, then lateral play in the shelf is reduced and positioning precision is improved, but the guide device structure becomes more complex
Solution Approach 1:
The guide device is merged with the inner container wall as an integral feature rather than being a separate component. The guide surface is formed directly on the wall, combining the functions of structural support and precise guidance into a single element. This merging reduces the number of parts and assembly steps, maintaining positioning precision while minimizing the increase in device complexity.
Solution Approach 2:
The guide surface performs multiple functions: it provides precise lateral guidance for the shelf, compensates for the draft angle, and serves as part of the support structure. This multi-functionality reduces the need for additional dedicated guidance components, achieving high positioning precision without proportionally increasing device complexity.
Data Source
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AI summary
The present invention relates to a refrigerator having an inner liner (201) that has an inner liner wall (203) having a support surface (207) for supporting a shelf (209) and a guide structure (211) on the support surface (207) for laterally guiding said shelf (209), said guide structure projecting relative to the inner liner wall (203).