Foldable Stroller Frame Nested Leg Assembly

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Solution Overview

Problem

Conventional foldable stroller frames have complex structures, resulting in relatively large folded volumes, making them inconvenient for storage and transport.

Innovation Solution

A stroller frame design featuring a main frame body, front and rear legs, a basket tube, seat-retaining members, and connecting assemblies, where the basket tube sections are pivotally connected to the legs and the connecting assemblies allow for the main frame sections to retract, enabling a compact folding mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional foldable stroller frame structure is used, then the stroller can be folded, but the folded volume is relatively large

Engineering Contradiction:
Improvefolded volumeVSAvoidstructure complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The stroller frame is divided into multiple independent leg assemblies (front legs and rear legs) that can be segmented and folded relative to each other. Each leg assembly includes separate components (leg tubes, connecting rods, support rods) that can be independently positioned during folding, allowing the overall structure to be divided into compact sections rather than moving as a single rigid unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The leg assemblies are designed to nest within each other during folding. The front legs and rear legs are configured to overlap and occupy the same spatial envelope when folded, with connecting rods and support rods arranged to fit within the boundaries of the main leg structures, achieving a compact nested configuration that minimizes folded volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If multiple connecting components are added to enable folding, then the stroller can be folded, but the structure becomes more complicated

Engineering Contradiction:
Improvefolding capabilityVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Multiple connecting functions are merged into integrated components. The connecting rods serve dual purposes as both structural support elements and folding articulation points. The support rods are combined with the leg assemblies such that they provide both structural support and folding capability, reducing the number of separate connecting components needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting rods and support rods are designed as multi-functional components that simultaneously provide structural support, enable folding motion, and maintain geometric stability. Each rod serves multiple functions within the mechanism, eliminating the need for dedicated separate components for each function and thereby reducing overall structural complexity.

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

Data Source

PatentEP2700559B1Foldable stroller frame
Publication Date: 2018.05.30 WONDERLAND SWITZERLAND AG
  • EP2700559B1 patent drawingFigure 1
  • EP2700559B1 patent drawingFigure 2
  • EP2700559B1 patent drawingFigure 3

AI summary

A stroller frame (1) includes a main frame body (10), two front legs (20), two rear legs (30), a basket tube (40), two seat-retaining members (50), and two connecting assemblies. The basket tube (40) includes a basket front tube section (41) and a basket rear tube section (42), each of which has two free ends. The two free ends of the basket front tube section (41) are connected respectively and pivotally to the two free ends of the basket rear tube section (42). The basket front tube section (41) is connected pivotally to the front legs (20). The basket rear tube section (42) is connected pivotally to the rear legs (30). Each of the connecting assemblies includes a basket-connecting member (72) having an upper end connected pivotally to a lower end of the main frame body (10), and a lower end connected pivotally to the basket rear tube section (42).