Cardboard Meal Box Locking Strip for Reliable Lid Closure
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Solution Overview
Problem
Cardboard meal boxes suffer from unreliable locking mechanisms due to the resilient nature of the material, leading to potential spillage of liquid or semi-liquid contents, especially when lids come undone or introduce gaps.
Innovation Solution
A cardboard meal box design featuring a hingedly connected lid with a skirt and a locking strip, where a tab-shaped cutout engages a ledge on the skirt to secure the lid, accompanied by cloud-shaped corner portions for additional flap engagement, ensuring a secure and consistent closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lid with hinge and flap locking means is used to close the container, then the lid can be secured to prevent opening, but the resilient cardboard material causes the locking means to be unreliable and allow the lid to come undone
Solution Approach 1:
The patent inverts the conventional locking approach by having the flap push the lid down onto the container rather than pulling it up. The downward force from the resilient flap material creates reliable engagement between the ledge and the tab-shaped cutout, overcoming the rebound effect that causes conventional locks to fail.
Solution Approach 2:
The locking mechanism uses simple, inexpensive cardboard components (ledge, tab-shaped cutout) that are integrated into the single blank structure. These elements are designed for single-use disposal rather than repeated use, eliminating the need for complex reusable locking mechanisms while ensuring reliable closure for the duration of transport.
2Object-affected harmful factors
If flaps are folded inward to form a top closure, then spillage can be prevented, but gaps or crevices may form between flaps allowing liquid to leak through
Solution Approach 1:
The patent employs nested flaps where inner flaps are positioned within outer flaps, creating overlapping layers that eliminate gaps and crevices. This nested arrangement ensures that liquid cannot leak through spaces between flaps while maintaining a compact structure that folds efficiently.
Solution Approach 2:
The meal box utilizes composite cardboard construction with multiple layers and materials of varying stiffness. The combination of resilient and rigid cardboard sections creates structural integrity at flap junctions, preventing gap formation while allowing the flaps to seal effectively against spillage.
3Ease of manufacture
If a single blank is used to manufacture the meal box with scores and creases, then manufacturing is simplified, but the resilient material tends to return to its planar state causing flaps to bias to opened position
Solution Approach 1:
The patent incorporates preliminary creasing and scoring patterns in the single blank design that pre-determine the three-dimensional configuration. These pre-formed creases guide the material to maintain its folded shape during assembly and use, counteracting the resilient tendency to return to the planar state without requiring additional fastening elements.
Solution Approach 2:
The patent varies the physical parameters of the cardboard material throughout the single blank, using regions of different stiffness, thickness, and elasticity. By strategically placing rigid sections at critical joint locations and more flexible sections in areas requiring movement, the design maintains stable flap positioning while preserving the simplicity of single-blank manufacturing.
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 design effectively mitigates spillage by providing a reliable locking mechanism with audible feedback, resisting upward movement of flaps, and minimizing gaps between flaps, thus ensuring the lid remains closed during transport and handling.
Implementation Method 1
the resilient behavior of the cardboard material... the resilient cardboard material has the tendency to return to its planar, two-dimensional state... the locking strip, which is partially fixed to an inner surface of the skirt... forms a ledge... the tab-shaped cutout engages the ledge to hold the lid in the closed position
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Cardboard meal box (1), comprising a container (3) for holding a meal, which is formed by a base and a plurality of walls extending upwardly from the base; and a lid (2) for closing the container, wherein a rear edge of the lid is hingedly connected to a first wall the plurality of walls of the container and the lid comprises a skirt (21) along its free edges, wherein, in a closed position of the lid, the skirt extends downwardly from the free edges of the lid; wherein a second wall (31) of the plurality of walls of the container comprises a flap (310) configured to be folded inwardly with respect to the container about a first fold line, and a tab-shaped cutout (311) extending from the first fold line away from the flap, wherein the flap and the tab-shaped cutout are configured to pivot about the first fold line in one piece, such that the tab-shaped cutout pivots outwards from the second wall, away from the container, upon the flap being folded inwards from the second wall, and wherein the skirt of the lid comprises a locking strip (4), which is partially fixed to an inner surface of the skirt, wherein a free edge of the locking strip, not being fixed to the inner surface of the skirt, forms a ledge (410), and wherein, in a closed position of the lid, the tab-shaped cutout engages the ledge to hold the lid in the closed position.