Foldable Push Chair With Geared 3D Leg Folding

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Solution Overview

Problem

Existing push chairs typically fold in only one or two dimensions, leading to inefficient storage and transportation due to their larger size when fully expanded.

Innovation Solution

A push chair design with a central body assembly and rotatable wheel supporting legs connected by a gearing system, allowing for folding in all three dimensions through synchronized rotation of forward and rearward extending legs using epicyclic or main and countershaft gearing systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the push chair is designed to fold in only one or two dimensions like conventional push chairs, then the structure is simpler, but the storage and transportation space requirements remain large

Engineering Contradiction:
Improvefolding volumeVSAvoidfolding mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The push chair is divided into multiple independent wheel supporting legs (front legs and rear legs) that can be folded separately. Each leg is connected to the central body assembly through independent folding mechanisms, allowing the chair to be segmented into smaller components for compact storage while maintaining structural integrity when unfolded.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wheel supporting legs are designed to nest within or alongside each other during the folding process. The front legs and rear legs fold in a coordinated manner to achieve three-dimensional compression, with components occupying overlapping spatial volumes in the folded state, similar to nested dolls.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the wheel supporting legs are connected without a gearing system, then the mechanism is simpler, but the folding operation becomes complex and requires careful manipulation

Engineering Contradiction:
Improvefolding operation easeVSAvoidgearing system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A gearing system acts as an intermediary mechanism between the wheel supporting legs and the central body assembly. This gearing system coordinates the folding motion of multiple legs simultaneously, translating a single user input into synchronized movement of all legs, thereby simplifying the user's interaction while managing the complexity internally.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The gearing system is designed to automatically coordinate the folding and unfolding of wheel supporting legs without requiring manual manipulation of each individual leg. Once the user initiates the folding action, the gearing mechanism self-regulates the motion distribution across all legs, making the operation intuitive and effortless.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If sliding bars and other supports are used to connect wheel supporting legs, then the structure is simpler, but fingers of users, items of clothing or other things can be trapped or entangled

Engineering Contradiction:
Improvetrapping hazardVSAvoidconnection mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces traditional sliding bar mechanisms with a gearing system that uses rotational motion and meshed gears to connect and coordinate the wheel supporting legs. This substitution eliminates the linear sliding interfaces that create trapping hazards, as the gearing system encloses all moving parts within toothed interfaces that cannot pinch or entangle fingers or clothing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 the push chair to fold into a more compact form, reducing storage and transportation space requirements without compromising structural integrity or user safety.

Implementation Method 1

the forward and rearward extending legs being coupled together such that they rotate in opposite directions around the central body during a folding or unfolding operation

Methodology Applied
Scientific EffectGear: Gear

Data Source

PatentEP4261104B1Push chair
Publication Date: 2026.01.21 JIJIBABA LTD
  • EP4261104B1 patent drawingFigure 1a
  • EP4261104B1 patent drawingFigure 1b
  • EP4261104B1 patent drawingFigure 1c

AI summary

The invention provides a foldable push chair comprising: a central body assembly extending across the push chair substantially horizontally and perpendicularly to the normal direction of travel of the push chair, a handle assembly connected to the central body and extending therefrom; at least three wheel supporting legs rotatable around the central body and extending from the central body, in the unfolded state one or more wheel supporting legs extending in a forward direction from the central body and one or more wheel supporting legs extending in a rearward direction from the central body; the forward and rearward extending legs being arranged such that they rotate in opposite directions around the central body during a folding or unfolding operation.