Expandable Tray Fold Structure for Volume Change and Nesting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing containers cannot simultaneously increase their inner volume and stack one inside another, while also allowing for the possibility of being stacked one inside another, while also being able to modify their inner volume as needed.

Innovation Solution

The design of a die-cut and cut cardboard sheet forming a tray with parallel fold lines and a concavity in the corners, allowing the side walls to expand outward when pressure is applied, and a trapezoid-shaped configuration for stacking, enabling both increased inner volume and compact stacking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the tray is designed with parallel fold lines to enable volume expansion, then the inner volume can be increased, but the tray cannot be stacked one inside another

Engineering Contradiction:
Improveinner volumeVSAvoidstacking ability
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The side walls are divided into multiple sections by parallel fold lines, allowing independent movement of each section. This segmentation enables the side walls to expand outward when pressure is applied, increasing the inner volume while maintaining the ability to collapse for stacking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tray transitions from a static structure to a dynamic one through the introduction of parallel fold lines. The side walls can dynamically adjust their position - remaining compact for stacking or expanding outward when pressure is applied to the upper edges, thus achieving both stacking ability and volume expansion.

Inventive Principle:
Principle #15Dynamics

2Volume of stationary object

If the tray is designed to fit one inside another for compact stacking, then the stack volume is reduced, but the inner volume cannot be increased

Engineering Contradiction:
Improvestack volumeVSAvoidinner volume
Core Design Contradiction:
Volume of stationary objectVSVolume of moving object

Solution Approach 1:

The trays are designed with a nested configuration where one tray can fit inside another when collapsed, reducing the stack volume. The trapezoid-shaped side walls with parallel fold lines allow the trays to nest efficiently while still permitting volume expansion when needed through the fold line mechanism.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The tray structure is made dynamic through parallel fold lines, allowing it to transition between a compact nested state for stacking and an expanded state for increased inner volume. The side walls can be displaced outward at the junction with the base, enabling volume increase without compromising stacking ability.

Inventive Principle:
Principle #15Dynamics

3Volume of moving object

If the side walls are made rigid to maintain structural strength, then the tray cannot expand its volume, but if they are made flexible to expand, then the structural strength is reduced

Engineering Contradiction:
Improveinner volumeVSAvoidstructural strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The side walls are segmented into multiple sections by parallel fold lines, distributing the structural load across multiple connection points. This segmentation allows the side walls to flex and expand while maintaining overall structural integrity through the distributed fold line architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The structural parameters of the side walls are optimized to balance flexibility and strength. The parallel fold lines are positioned and dimensioned to allow controlled displacement outward while maintaining sufficient structural strength to support the expanded volume and withstand handling forces.

Inventive Principle:
Principle #35Parameter changes

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 tray achieves both increased inner volume through expansion and compact stacking by using a die-cut cardboard sheet with parallel fold lines and a concavity, allowing for efficient use of space.

Implementation Method 1

at least two fold lines parallel to one another are arranged at the junction end of at least one of the side walls of the tray with the base

Methodology Applied
Scientific EffectFolding: Folding

Implementation Method 2

A concavity is formed in each of the corners formed between contiguous sides of the base

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP4335772B1Expandable tray
Publication Date: 2025.12.24 PACK
  • EP4335772B1 patent drawingFigure 1
  • EP4335772B1 patent drawingFigure 2
  • EP4335772B1 patent drawingFigure 3

AI summary

A tray comprising a base (1), wherein there emerges from each side of the base (1) a trapezoid-shaped side wall which is narrower at the junction with the base than at its free edge, such that when the side walls are folded with respect to the base, a truncated pyramid-shaped assembly is formed, in addition, on each side wall at the junction area with respect to the base at least twofold lines are arranged parallel to one another at the junction with the base, thereby achieving a tray whose inner volume can be modified based on the pressure exerted on the upper edge of the side walls, and on the other hand the trays can be arranged in a fitted manner one inside another, offering a smaller final stack volume.