Foldable Stroller Frame Two-Stage Folding Mechanism

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Solution Overview

Problem

Existing stroller folding mechanisms fail to achieve optimal compactness in the folded position, making storage and transport challenging, and often require complex and unsafe folding processes.

Innovation Solution

A stroller frame with a central beam and articulated arms that allows for two-stage folding, where the upper part folds first, unlocking the lower part to bring rear wheels closer to the central beam, offering optional intermediate and compact folding modes with user-controlled unlocking mechanisms to prevent accidental folding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the stroller is folded using conventional mechanisms, then the folding operation is simple, but the folded width remains significant and compactness is not optimal

Engineering Contradiction:
Improvefolded widthVSAvoidfolding mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The folding mechanism is divided into two independent stages: upper part folding and lower part folding. The upper part folding mechanism and lower part folding mechanism are separated, with each stage controlled by independent locking means. This segmentation allows the stroller to achieve compact folded width while maintaining manageable complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the folding mechanism allows easy folding operations, then the user can perform folding quickly, but safety control becomes difficult and unwanted folding may occur

Engineering Contradiction:
Improvefolding operation easeVSAvoidfolding safety control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking means are designed to automatically engage and lock the folding parts at each stage before the user completes the folding motion. The first locking means engages the upper part folding mechanism, and the second locking means engages the lower part folding mechanism. This preliminary locking action prevents accidental folding while allowing easy deliberate folding operations.

Inventive Principle:
Principle #10Preliminary action

3Volume of moving object

If the stroller achieves compact folded position, then storage and transport are facilitated, but the folding mechanism becomes more complex and costly to manufacture

Engineering Contradiction:
Improvefolded sizeVSAvoidmanufacturing simplicity and cost
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The folding mechanism uses nested locking means where the first locking means is integrated into the upper part folding mechanism and the second locking means is integrated into the lower part folding mechanism. Each locking means is contained within its respective folding stage, creating a compact nested structure that achieves small folded size while using simple, cost-effective components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3507168B1Foldable stroller frame and corresponding stroller
Publication Date: 2021.03.31 DOREL FRANCE SA
  • EP3507168B1 patent drawingFigure 1
  • EP3507168B1 patent drawingFigure 2
  • EP3507168B1 patent drawingFigure 3A~3B

AI summary

Stroller and foldable stroller frame, comprising an upper portion which can take up an unfolded upper portion position and a folded upper portion position, and a lower portion which has a central beam (601) which carries at least one front wheel and two rear wheels, with respective supports (63, 64) each connected to the central beam (601) by an assembly of two parallel arms (632, 633) which are articulated on the central beam so as to be able to take up an unfolded position of the rear wheels and a folded position of the rear wheels, in which the rear wheels are moved towards the beam (601). First means (71, 81, 83) for blocking the folding of said lower portion, which are controlled by the folding of the upper portion, act in such a manner that the movement from the unfolded position of the rear wheels to the folded position of the rear wheels is possible only when the upper portion is in the folded upper portion position.