Cardboard Crate Edge Flap Reinforcement for Bulging Resistance

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Solution Overview

Problem

Stackable cardboard crates face issues with lateral bulging, particularly under transverse forces, due to the lack of effective shear-resistant connections between adjacent wall parts, which limits their strength and resistance to bulging despite material reinforcement.

Innovation Solution

The edge flaps of the crate are bent back and glued to the jacket, forming a support web that connects to a triangular support section, enhancing the bulging resistance through additional cardboard layers and improved flexural rigidity, either directly or via a connecting web, to distribute loads effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If edge flaps are bent back to form support ribs with triangular cross-section, then load-bearing capacity is improved, but lateral bulging resistance deteriorates under shear force

Engineering Contradiction:
Improveload-bearing capacityVSAvoidlateral bulging
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent combines multiple cardboard layers (edge flap + folded flap + connecting web) to create a composite reinforcement structure. This composite construction increases both load-bearing capacity and bulging resistance by distributing stresses across multiple bonded layers, resolving the contradiction between strength improvement and bulging prevention.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The folded flap extends in a third dimension perpendicular to the support rib, creating a multi-dimensional reinforcement structure. This additional dimensional element (the folded flap protruding from the support rib) provides extra resistance to lateral bulging while maintaining the load-bearing function of the support rib.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If folded flap is attached directly to inclined support rib, then bending stiffness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvebending stiffnessVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The folded flap is formed from the same cardboard material as the support rib itself, using the existing material rather than adding separate reinforcement elements. This self-service approach increases bending stiffness while minimizing manufacturing complexity, as the reinforcement is created from the base material through folding and gluing operations.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If connecting web is introduced to attach folded flap, then structural stability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidease of manufacture
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The connecting web merges the folded flap with the support rib structure, creating an integrated reinforcement system. This combining of elements improves structural stability by ensuring rigid connection between components, while the web is designed to be formed from the same cardboard stock, maintaining ease of manufacture through unified material processing.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3523209B1Crate in the form of a flap-adhered box made of cardboard
Publication Date: 2021.07.21 MAIER GOTTFRIED
  • EP3523209B1 patent drawingFigure 1
  • EP3523209B1 patent drawingFigure 2
  • EP3523209B1 patent drawingFigure 3

AI summary

The invention relates to a crate in the form of a flap-adhered box made of cardboard, comprising a base (1) and a casing (2) which projects from the base (1), said casing forming upper longitudinal edge portions that are reinforced by edge flaps (6) folded inwards between the casing corners and have corner portions (8) which protrude upward and correspond to base recesses (19) and between which a support portion (9) of the the edge flaps (6) is bent back towards the casing (2) about two crease lines (11) that are set back relative to the folding lines (10) of the corner portions (8), thereby forming a support web (12) which is parallel to the base. The aim of the invention is to improve the bending stiffness of the casing. This is achieved in that the edge flaps (6) bent back towards the casing (2) are provided with a folding flap (17), which is bent back towards the support web (12) about a folding line (16) and which is adhered to the casing (2), on the flap face facing the casing (2).