Collapsible Wagon Folding Structure for Reduced Folded Height

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Solution Overview

Problem

Existing collapsible wagons have a small unfolded capacity and a large folded volume, making them inconvenient for storage in space-limited areas.

Innovation Solution

A collapsible wagon design with a height-reduced folded state, featuring a collapsible structure with standing posts, folding mechanisms, and sliding sleeves, along with lifting tubes and suspension rods, allowing for increased unfolded capacity while maintaining a compact folded size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the collapsible wagon is designed with traditional folding mechanisms, then it can be folded for storage, but the folded volume is large and takes up too much space

Engineering Contradiction:
Improvefolded volumeVSAvoidstorage convenience
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent applies nesting by placing the folded wagon structure inside itself. The folding mechanisms are designed so that the standing posts, cross tubes, and other components nest within each other in a compact arrangement, significantly reducing the folded volume compared to traditional side-by-side folding configurations.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from traditional horizontal folding to vertical folding along the standing posts. By arranging the folding mechanisms to fold upward and downward along the vertical dimension rather than outward horizontally, the wagon achieves a compact folded height that fits better in vertical storage spaces like car trunks.

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

2Volume of moving object

If the collapsible wagon is designed with compact folding mechanisms, then the folded volume is reduced, but the unfolded capacity becomes even smaller

Engineering Contradiction:
Improvefolded volumeVSAvoidunfolded capacity
Core Design Contradiction:
Volume of moving objectVSVolume of stationary object

Solution Approach 1:

The patent employs dynamic folding mechanisms with multiple degrees of freedom that allow the structure to transition smoothly between compact folded and expanded unfolded states. The folding mechanisms include sliding sleeves, rotating joints, and telescopic components that enable the wagon to achieve both compact folding and full expansion capacity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The wagon structure is divided into multiple independent folding segments including first, second, third, and fourth folding mechanisms. Each segment can fold and unfold independently, allowing the overall structure to achieve compact folding while maintaining full unfolded capacity through the coordinated expansion of all segments.

Inventive Principle:
Principle #1Segmentation

3Volume of stationary object

If the folding mechanisms are made more complex to increase unfolded capacity, then the unfolded capacity increases, but the device complexity increases

Engineering Contradiction:
Improveunfolded capacityVSAvoidfolding mechanism complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The patent designs universal folding mechanism components that serve multiple functions. The sliding sleeves, cross tubes, and connecting joints are designed to simultaneously provide folding motion, structural support, and capacity expansion. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple functions into integrated components. The folding mechanisms combine support functions, folding functions, and capacity expansion functions into unified structures rather than using separate components for each function, thereby reducing the overall number of parts and simplifying the device.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the unfolded capacity of the wagon while ensuring a reduced folded height, improving user convenience in storage and transportation.

Implementation Method 1

first sliding sleeves respectively slidably provided on the standing posts

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the short tube is provided with a second sliding sleeve

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

the first suspension rod and the second suspension rod are flexible rods; and in a process of folding the collapsible wagon, the first suspension rod and the second suspension rod deform

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

the lifting tube is slidably connected to the upper end of the corresponding standing post

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4674725B1Collapsible wagon and wagon with height reduced after being folded
Publication Date: 2026.05.13 JINHUA MUTAO LEISURE PRODUCTS CO LTD
  • EP4674725B1 patent drawingFigure 1
  • EP4674725B1 patent drawingFigure 2
  • EP4674725B1 patent drawingFigure 3

AI summary

The collapsible wagon includes four standing posts, a bottom folding mechanism, a first, third, second and fourth folding mechanism, and first sliding sleeves, where the first sliding sleeves are respectively slidably provided on the standing posts, and are respectively hinged to short tubes. Each of the first and the second folding mechanism includes a first, third and a second crossing assembly that are hinged in sequence; each of the first and the second crossing assembly includes a first and a second cross tube; the first cross tube is hinged to an upper end of the corresponding standing post; the short tube is hinged to the first cross tube and provided with a second sliding sleeve; the second cross tube is hinged to the second sliding sleeve of the corresponding short tube; and folded heights of the first, the third and the second crossing assembly, the third and the fourth folding mechanism and the bottom folding mechanism are not greater than a height of the upper end of the standing post.