Collapsible Wagon Steering Linkage for Stable Omnidirectional Wheels

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Solution Overview

Problem

Inclined-fork universal wheels in foldable carts are difficult to control, especially on uneven terrain and under load, leading to instability and inconvenience in steering, particularly when used outdoors.

Innovation Solution

A collapsible and person-carrying structure for collapsible wagon steering system featuring a foldable frame with steering wheels connected by wheel steering swing arms and a steering rod assembly, allowing for controlled movement and stability using straight-fork universal wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If inclined-fork universal wheels are used to facilitate steering, then steering convenience is improved, but control stability deteriorates under load and on inclined roads

Engineering Contradiction:
Improvesteering convenienceVSAvoidcontrol stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent inverts the traditional inclined-fork universal wheel design by using a straight-fork configuration where the wheel axis and rotation axis are located on the same vertical line. This inversion resolves the control stability issue while maintaining steering convenience through the four-bar linkage mechanism that provides controlled movement.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a four-bar linkage mechanism as an intermediary between the straight-fork universal wheel and the cart body. This intermediary controls the wheel's movement, preventing uncontrolled rotation on inclined roads while preserving the steering convenience provided by the universal wheel design.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If inclined-fork universal wheels are used for free steering capability, then steering flexibility is improved, but steering control difficulty increases on rugged terrain

Engineering Contradiction:
Improvesteering flexibilityVSAvoidsteering control difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent employs a dynamic four-bar linkage mechanism that adapts to terrain conditions. The linkage allows the wheel to rotate freely on flat surfaces for flexibility, but automatically constrains movement on inclined or rugged terrain to reduce control difficulty, providing context-dependent behavior.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the geometric parameters of the wheel assembly by using a straight-fork configuration instead of inclined-fork. This parameter change, combined with the four-bar linkage, modifies the wheel's movement characteristics to reduce control difficulty on rugged terrain while maintaining steering flexibility.

Inventive Principle:
Principle #35Parameter changes

3Power

If inclined-fork universal wheels are used to rotate in direction of force transmission, then power transmission efficiency is improved, but steering control precision deteriorates

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidsteering control precision
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The four-bar linkage acts as an intermediary that transmits power efficiently from the wheel to the cart body while simultaneously providing precise control over the wheel's orientation. The linkage's geometric constraints ensure that power transmission occurs along controlled paths, improving both efficiency and precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If straight-fork universal wheels are used instead of inclined-fork, then operational stability is improved, but steering complexity increases

Engineering Contradiction:
Improveoperational stabilityVSAvoidsteering complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the steering system into distinct functional components: the straight-fork universal wheel for stable power transmission, the four-bar linkage for controlled movement, and the connection to the cart body. This segmentation allows each component to perform its function optimally while the overall system remains manageable in complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4678507A1Collapsible and person-carrying structure for collapsible wagon steering system
Publication Date: 2026.01.14 SHENZHEN CHEPINYI TECH CO LTD
  • EP4678507A1 patent drawingFigure 1
  • EP4678507A1 patent drawingFigure 2
  • EP4678507A1 patent drawingFigure 3

AI summary

Disclosed is a collapsible and person-carrying structure for a collapsible wagon steering system, comprising a collapsible frame. A connection device is fixedly connected to the lower end of one side of the collapsible frame; the connection device comprises a frame support base; directional wheels are connected to the bottom of the frame; the directional wheels are connected to a steering structure by means of wheel direction swing arms; the steering structure is collapsible; a directional rod assembly is further connected to the steering structure; and the directional rod assembly is used for controlling motion of the steering structure. By adopting the design, a steering structure composed of a plurality of steering arms is arranged between two directional wheels, steering of the directional wheels is controlled by means of the steering structure, and the steering structure can be switched between an uncollapsed state and a collapsed state so as to adapt to folding of the collapsible frame, such that the present invention is easy to control and practical; and the directional wheels can be replaced with straight-blade fork omnidirectional wheels, such that the traveling stability of a wagon is improved, the use safety is high, and the steering is simpler. The present invention has reasonable design, a simple structure, and low costs.