Child Stroller Linkage for Smooth Folding and Stable Unfolding

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Solution Overview

Problem

Existing child strollers face challenges in providing a smooth and convenient folding and unfolding mechanism, which is crucial for convenient storage and transport.

Innovation Solution

The child stroller apparatus incorporates a first leg frame, a second leg frame, a handle frame, a seat assembly, and a linkage system with a support bar, slider, and frame link, allowing for smooth folding and unfolding through a four-bar linkage mechanism and locking mechanisms to stabilize the stroller in both states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional folding mechanism is used, then the stroller can be folded for storage, but the folding and unfolding operation becomes complex and inconvenient

Engineering Contradiction:
Improvefolding and unfolding convenienceVSAvoidframe construction complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The stroller frame is divided into multiple segments (first leg frame, second leg frame, handle frame with side segments) that can be independently positioned and connected through the linkage mechanism, allowing simplified folding operations while maintaining structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A linkage mechanism comprising a support bar, slider, and frame link is introduced as an intermediary between the leg frames and handle frame. This intermediary mechanism coordinates the movement of multiple frame segments, transforming a complex multi-joint folding operation into a simpler single-action operation for the user

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the stroller is designed to fold compactly, then storage volume is reduced, but the stability during use may be compromised

Engineering Contradiction:
Improvefolded storage volumeVSAvoidstroller stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The linkage mechanism provides dynamic adaptation: during unfolded use, the mechanism maintains the frame in a stable open configuration; during folding, the same mechanism enables compact consolidation. The system transitions between states while maintaining stability in each state through the coordinated movement of the support bar, slider, and frame link

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The geometric parameters of the frame configuration are changed through the linkage mechanism. The support bar and frame link adjust the relative positions and angles of the leg frames and handle frame, enabling transformation from an extended stable configuration to a compact folded configuration while maintaining structural integrity throughout the transition

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

Enables easy and efficient folding and unfolding of the stroller, enhancing convenience and reducing the volume for storage, while maintaining stability and safety during use.

Implementation Method 1

The third side segment is pivotally connected to the first side segment via an articulation

Methodology Applied
Scientific EffectPivotal connection: Hinge

Implementation Method 2

The support bar is respectively connected pivotally to the first side segment and the second side segment

Methodology Applied
Scientific EffectPivotal connection: Hinge

Implementation Method 3

the slider is coupled to the seat assembly and is slidably connected to the support bar, and the frame link is pivotally connected to the slider, the slider sliding along the support bar during folding and unfolding of the child stroller apparatus

Methodology Applied
Scientific EffectSliding: Friction

Data Source

PatentEP4469333B1Child stroller apparatus
Publication Date: 2025.12.31 WONDERLAND SWITZERLAND AG
  • EP4469333B1 patent drawingFigure 1
  • EP4469333B1 patent drawingFigure 2
  • EP4469333B1 patent drawingFigure 3

AI summary

A child stroller apparatus (100) includes a first leg frame (102) having a first side segment (102A), a second leg frame (104) having a second side segment (104A), a handle frame (106) having a third side segment (106A), a seat assembly (108) coupled to the first side segment (102A), and a linkage (110) including a support bar (132), a slider (134) and a frame link (136). The third side segment (106A) is respectively connected pivotally to the first side segment (102A) and the second side segment (104A), wherein the third side segment (106A) is pivotally connected to the first side segment (102A) via an articulation (114). The support bar (132) is respectively connected pivotally to the first side segment (102A) and the second side segment (104A), the slider (134) is coupled to the seat assembly (108) and is slidably connected to the support bar (132), and the frame link (136) is pivotally connected to the slider (134), the slider (134) sliding along the support bar (132) during folding and unfolding of the child stroller apparatus (100).