Collapsible Cart Handle and Wheel Folding Mechanism

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Solution Overview

Problem

Current folding wagons have complex folding mechanisms, poor stability when unfolded, and unstable wheels, making them inconvenient to use and store.

Innovation Solution

A folding wagon design that allows the handle and wheels to be extended or folded simultaneously, featuring a simple structure with a 90° rotating mechanism for the wheel assemblies and a U-shaped guide rail for easy operation and stability, along with a handle latch assembly for secure folding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the handle and wheels are folded separately in known folding trolleys, then the folding function is achieved, but the structure becomes complicated and the folding procedure becomes complex

Engineering Contradiction:
Improvefolding functionVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the handle folding mechanism and wheel folding mechanism into a single integrated system. The drive rod simultaneously controls both the handle rotation (via L-shaped structure pressing against rotating part) and the wheel assembly folding (via connecting rod), allowing both components to fold together in one action rather than requiring separate folding operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive rod serves multiple functions: it rotates around the base plate to control handle folding, simultaneously drives the connecting rod to control wheel assembly folding, and works with spring parts to provide both folding force and resetting force. This multi-functional component reduces the need for separate mechanisms for each folding operation.

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

2Adaptability or versatility

If the handle and wheels are folded separately in known folding trolleys, then the folding function is achieved, but the operation convenience deteriorates

Engineering Contradiction:
Improvefolding functionVSAvoidfolding operation convenience
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent merges the folding operations of the handle and wheels into a single simultaneous action. When the drive rod rotates, it concurrently actuates the handle rotation mechanism and the wheel assembly folding mechanism through the L-shaped structure and connecting rod, respectively, allowing the user to fold both components with one motion rather than multiple separate operations.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If simple folding mechanisms are used, then the structure is simplified, but the stability of the folding trolley becomes poor when unfolded

Engineering Contradiction:
Improvestructure simplicityVSAvoidunfolded state stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent divides the wheel assembly into separable components (wheel, connecting rod, rotating part) that can be independently positioned and locked. The connecting rod can be rotated to different positions (including a horizontal position) to provide structural support, and the modular design allows for stable configuration when unfolded while maintaining folding capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting rod acts as an intermediary element between the drive mechanism and the wheel assembly. It transmits the folding motion when needed but can also be positioned horizontally to provide structural support and stability when the trolley is unfolded, serving both folding and stabilizing functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If the wheels are made stable when stacked, then the storage efficiency is improved, but the structure becomes more complex

Engineering Contradiction:
Improvestorage efficiencyVSAvoidfolding mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the handle folding and wheel folding into a single simultaneous operation controlled by the drive rod. This integration means that when the trolley is folded for storage, both the handle and wheels are folded together in one action, creating a more compact storage configuration without requiring additional separate folding mechanisms.

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 provides a stable and easy-to-use folding wagon with a simplified folding mechanism, improving storage efficiency and operational convenience by allowing simultaneous folding and unfolding of the handle and wheels.

Implementation Method 1

the first spring part extending rearward to push the first rotating part away from the first fixed part, while the first spring part is reset and twisted and the first rotating part is rotated by 90°

Methodology Applied
Scientific EffectElastic potential energy: Spring

Data Source

PatentEP3766759B1Collapsible cart
Publication Date: 2023.04.19 SAAME TOOLS SHANGHAI IMPORT & EXPORT CO LTD
  • EP3766759B1 patent drawingFigure 1~2
  • EP3766759B1 patent drawingFigure 3
  • EP3766759B1 patent drawingFigure 4~5

AI summary

Folding carriage, wherein one end of the drive rod is connected to the base plate and can be rotated. The connection point of the drive rod and the base plate has an L-shaped structure (210). The horizontal rod (310) is attached to the base plate. The first fixed part (410) is positioned on and attached to the horizontal rod (310). The first rotating part (420) is connected to the horizontal rod (310) by a sleeve with a cover, and one end is connected to the end of the L-shaped structure (210). The first spring element is positioned between the first fixed part (410) and the first rotating part (420). When the first rotating part (420) and the first fixed part (410) are aligned, the two ends of the first spring element (430) are twisted at a defined angle and fixed to the first fixed part (410) and the first rotating part (420), respectively.The first wheel assembly (500) rotates together with the first rotating part (420). The handle (200) and the wheels (520, 720) fold open or closed simultaneously in one action.