Cardboard Tray with Double-Layer Walls for Secure Lid Engagement
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Solution Overview
Problem
Existing cardboard trays struggle with ease of stacking when empty or full, and plastic lids often fail to fit securely or open easily due to differences in material strength, leading to potential spillage and contamination.
Innovation Solution
A cardboard tray design with a basal wall featuring three walls, each with a double layer and longitudinal through holes and projections, allowing for secure engagement with a lid through embossings, ensuring easy stacking and opening while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plastic lids are used with cardboard trays, then secure engagement is achieved, but material strength differences cause fitting or opening difficulties
Solution Approach 1:
The patent applies local quality by creating specific engagement features (protrusions and recesses) at localized positions on the lid and tray rather than uniform engagement across the entire structure. This allows different regions to have different properties: the engagement zones provide strong mechanical interlocking while the rest of the cardboard structure maintains its inherent flexibility and ease of opening.
Solution Approach 2:
The patent employs composite materials by combining cardboard (cellulose-based) for the tray body with plastic for the lid and engagement features. This composite approach leverages the strengths of each material: plastic provides rigidity and precision for secure engagement, while cardboard maintains its advantages of being lightweight and easy to open. The engagement features are specifically designed to accommodate the different mechanical properties of these materials.
2Ease of manufacture
If cardboard trays are designed with simple structure, then manufacturing is easier, but stacking capability when empty or full is compromised
Solution Approach 1:
The patent applies segmentation by dividing the tray wall structure into multiple layers (first wall layer, second wall layer) with distinct functions. The first layer provides structural integrity for stacking, while the second layer incorporates engagement features for lid attachment. This segmentation allows each layer to be optimized for its specific purpose without compromising the overall simplicity of manufacturing.
Solution Approach 2:
The patent utilizes another dimension by adding vertical layering (multiple wall layers) to the tray structure. Instead of complicating the horizontal geometry, the invention stacks functional layers vertically: the first layer handles stacking stability, while the second layer provides lid engagement. This dimensional approach maintains manufacturing simplicity while achieving multiple functional requirements.
3Strength
If cardboard wall strength is increased for secure lid fitting, then lid engagement improves, but tray becomes difficult to open and may spill contents
Solution Approach 1:
The patent segments the wall structure into functional layers: the first wall layer maintains adequate strength for lid engagement, while the second wall layer incorporates engagement features that distribute mechanical stresses. This segmentation prevents the entire wall from becoming overly rigid, allowing the tray to remain easy to open while still providing secure lid fitting.
Solution Approach 2:
The patent applies local quality by concentrating the strength enhancement only where needed for lid engagement (through the engagement features in the second wall layer) rather than uniformly increasing the strength of the entire cardboard structure. This localized approach maintains opening ease in non-engagement areas while providing sufficient strength where required.
4Productivity
If cardboard tray structure is simplified for ease of manufacture, then production efficiency increases, but stacking capability when empty or full deteriorates
Solution Approach 1:
The patent segments the manufacturing process and structure into modular layers that can be produced efficiently. The first wall layer can be manufactured using standard cardboard forming processes, while the second layer with engagement features can be added through controlled deformation and forming operations. This segmentation maintains high productivity while achieving the structural complexity needed for stable stacking.
Solution Approach 2:
The patent applies preliminary action by pre-forming the engagement features and structural elements during the manufacturing process itself, rather than requiring post-manufacturing assembly steps. The controlled deformation and forming operations create the necessary structural features (protrusions, recesses, layered walls) directly during production, maintaining manufacturing efficiency while ensuring stacking stability.
Data Source
AI summary
Tray (21) having a cardboard base (1) and at least a first wall (3a) and a second wall (3b) formed by a first layer and a second layer each having at least one hole (6), the second layer of the first wall having a first planar projection (12), forming an angle with the first wall of between 30° and 90° arranged to retain a first embossing of a lid, the second layer of the second wall having a second planar projection forming an angle with the second wall of between 30° and 90° to retain a second embossing of the lid.