Multi-Mode Luggage Sub-Frame for Upright and Tilt Stability

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Solution Overview

Problem

Existing dual-mode luggage bags require complex structures with additional wheels and struts that compromise carrying space and functionality, limiting their use to either child-carrying or upright configurations, and often necessitate expensive manufacturing.

Innovation Solution

A separate wheeled sub-frame that mounts on the luggage base, allowing for dual modes of operation by changing the center of gravity through geometric relationships and pivot axes, enabling smooth transitions between upright and tilt modes without intruding into the bag's volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional wheels and struts are integrated into the bag frame for dual-mode functionality, then the bag can operate in both upright and child-carrying modes, but the carrying space inside the bag is compromised and the device complexity increases

Engineering Contradiction:
Improvedual-mode functionalityVSAvoidcarrying space
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The invention separates the child-carrying support structure from the main bag frame by using an external A-frame assembly that attaches to the bag exterior. This segmentation allows the bag to maintain its full internal carrying space while the A-frame provides the necessary support structure for child-carrying mode without intruding into the bag cavity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The A-frame assembly acts as an intermediary structure between the bag and the child seat. It provides the necessary structural support and wheel mounting while keeping the bag frame simple and unobtrusive. The A-frame connects to the bag at specific attachment points and provides the mechanical advantage needed for stable child-carrying operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If additional wheels and struts are integrated into the bag frame for dual-mode functionality, then the bag can operate in both upright and child-carrying modes, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedual-mode functionalityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention divides the system into separate functional modules: the bag itself, the A-frame assembly, and the wheel system. This segmentation allows each component to be optimized independently and simplifies manufacturing and assembly. The A-frame assembly can be produced as a separate unit and attached to the bag, reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The A-frame assembly serves multiple functions: it provides structural support for child-carrying mode, mounts the wheels, and attaches to the bag. This multi-functionality reduces the need for separate components and simplifies the overall device structure while enabling dual-mode operation.

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

3Adaptability or versatility

If the bag is reconfigured to carry a child or smaller suitcase on the portion between the bag top and extended handle height, then the bag can carry additional loads, but the centre of gravity shifts causing the bag to tip over or require more force to hold the handle

Engineering Contradiction:
Improveload carrying capabilityVSAvoidcentre of gravity stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The A-frame assembly is designed with a geometry that positions the wheels and support structure to counterbalance the shifted center of gravity when a child or additional load is carried on the bag top. The A-frame extends downward and outward, creating a stable triangular support structure that prevents tipping and distributes the weight more evenly.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The A-frame assembly is pre-configured with the appropriate geometry and wheel placement to automatically compensate for center of gravity shifts when the bag is placed in child-carrying mode. The structure is designed in advance to provide the necessary stability without requiring active adjustment during use.

Inventive Principle:
Principle #10Preliminary action

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 solution provides stable support in both modes, reduces complexity and cost, maintains carrying space, and allows for both pushing and pulling, overcoming the limitations of traditional dual-mode bags.

Implementation Method 1

The geometry of the relationship between the bag frame and sub-frame of the luggage apparatus urges the bag to tilt and return upright

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

the sub-frame and bag frame geometry defined by three pivot axes, rotation about the three pivot axes moving the bag frame between the upright mode and tilt modes

Methodology Applied
Scientific EffectRotation:

Data Source

PatentEP4030959B1Multi-mode luggage apparatus and method
Publication Date: 2025.10.22 PHIL & TEDS DESIGN
  • EP4030959B1 patent drawingFigure 1
  • EP4030959B1 patent drawingFigure 2
  • EP4030959B1 patent drawingFigure 3

AI summary

A luggage apparatus and method is described herein that introduce a separate wheeled sub-frame that mounts on the base of a luggage apparatus and which allows for dual mode use between an upright mode and a tilt mode. The geometry of the relationship between the bag frame and sub-frame of the luggage apparatus urges the bag to tilt and return upright. The luggage apparatus is securely supported about the sub-frame in both modes with a changing centre of gravity and can be pushed or pulled in either mode.