Foldable Cart Frame With Adjustable Wheel Orientation

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Solution Overview

Problem

Existing foldable carts are inconvenient to operate, not small enough after folding, and lack flexibility in wheel adjustment, making them unsatisfactory for various use scenarios.

Innovation Solution

A foldable cart design featuring a handle assembly, foldable cart frame with vertical rods, wheel frame assembly, and omni-directional wheels, allowing for folding and unfolding, and adjustable wheel directionality through a mechanism involving crossed rotatable drawing rods and joints, with detachable components for compact storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cart is designed as a foldable structure, then the storage convenience is improved, but the operating convenience deteriorates

Engineering Contradiction:
Improvestorage convenienceVSAvoidoperating convenience
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The cart frame is divided into multiple detachable components including front rod assembly, rear rod assembly, connecting rods, and wheel assembly. These segments can be separated and stored independently, improving storage convenience while maintaining operational integrity when assembled

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cart incorporates rotatable connecting rods that can dynamically adjust between extended operational position and retracted storage position. The drawing rods with rotatable joints enable the cart to transition smoothly between folded and unfolded states, resolving the contradiction between storage compactness and operational convenience

Inventive Principle:
Principle #15Dynamics

2Volume of stationary object

If the cart is designed as a foldable structure, then the storage size is reduced, but the folded size is still not small enough

Engineering Contradiction:
Improvestorage sizeVSAvoidfolded size
Core Design Contradiction:
Volume of stationary objectVSVolume of moving object

Solution Approach 1:

The front rod assembly and rear rod assembly are designed to nest within each other when folded, with the connecting rods collapsing into a compact configuration. The wheel assembly can be detached and stored separately, enabling the main frame to be compressed to minimal dimensions for storage

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

By segmenting the frame into detachable rod assemblies and wheel components, each part can be independently collapsed and stored. The connecting rods with rotatable joints allow the frame segments to fold flat against each other, achieving compact folded dimensions

Inventive Principle:
Principle #1Segmentation

3Device complexity

If the cart uses fixed casters, then the structure is simple, but the flexibility in use is insufficient

Engineering Contradiction:
Improvestructure simplicityVSAvoidflexibility in use
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The cart employs rotatable connecting rods with joints that can dynamically adjust the wheel orientation and cart configuration. The drawing rods can rotate to change the direction of wheel assembly, enabling the cart to adapt to different terrains and usage scenarios while maintaining relatively simple structure

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rotatable joint mechanism serves multiple functions: it enables folding for storage, adjusts wheel orientation for different terrains, and allows configuration changes for various usage scenarios. This multi-functionality provides flexibility without significantly increasing structural complexity

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

Data Source

PatentEP4393790B1A foldable cart
Publication Date: 2026.02.04 PHAETON MFG LLC
  • EP4393790B1 patent drawingFigure 1
  • EP4393790B1 patent drawingFigure 2~3
  • EP4393790B1 patent drawingFigure 4~5

AI summary

The foldable cart comprises a handle assembly, four vertical rods, a wheel frame assembly, a plurality of wheels and a storage bag. Each vertical rod is connected to the wheel frame assembly; the wheel frame assembly is in an X-shaped foldable structure, the storage bag is connected to the four vertical rods, and, the lower end of the handle assembly is rotatably connected to the bottom ends of the two vertical rods on the corresponding side of the cart frame and is foldable with the two vertical rods. The foldable cart of the présent invention is simple and reasonable in structure, small in size after being folded and convenient to store and carry.