Suitcase Coupler and Hidden Strap for Secondary Bag Attachment

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Solution Overview

Problem

Traveling with multiple bags can be cumbersome and unwieldy due to the difficulty in effectively coupling a secondary bag to a suitcase, especially when airline restrictions limit the number of carry-on bags.

Innovation Solution

A suitcase with a coupler and adjustable strap system that allows a secondary bag to be securely attached and hidden when not in use, featuring a collapsible handle with interchangeable grips for customization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple bags are carried separately, then each bag can be individually managed, but it becomes cumbersome and uncomfortable

Engineering Contradiction:
ImproveEase of carryingVSAvoidNumber of bags
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent combines multiple bags into a single integrated unit by providing a primary bag with an integrated secondary bag that can be coupled to the exterior. This merging approach allows travelers to manage multiple bags as one unified system, eliminating the need to separately carry multiple independent bags while still providing separate storage compartments for different items.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated secondary bag system provides multi-functionality by serving as both a separate carry-on bag when needed and as an attached accessory to the primary bag when not needed. The coupling mechanism allows the secondary bag to be securely attached to the primary bag or removed independently, providing universal utility for different travel scenarios.

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

2Stability of the object's composition

If multiple bags are stacked or joined together, then they can be carried as one unit, but it becomes unsteady and unwieldy

Engineering Contradiction:
ImproveStability of bag arrangementVSAvoidComplexity of coupling system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent segments the coupling system into distinct functional components: a coupling mechanism attached to the primary bag, a detachable connector, and the secondary bag with its own attachment points. This segmentation allows each component to perform its specific function independently, creating a stable connection without requiring a complex integrated system. The modular design simplifies the overall complexity while maintaining stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary coupling mechanism that acts as a mediator between the primary bag and secondary bag. This intermediary component provides a stable connection point that distributes weight and force evenly, preventing the unsteady and unwieldy arrangement that occurs with direct stacking. The coupling mechanism serves as a buffer that maintains stability while reducing the complexity of direct bag-to-bag connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a coupler is provided to attach the secondary bag, then secure attachment is achieved, but the appearance becomes less refined when not in use

Engineering Contradiction:
ImproveSecurity of attachmentVSAvoidAppearance of suitcase
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent employs a dynamic coupling system where the coupler can transition between different states: engaged (providing secure attachment) and disengaged (providing clean appearance). The coupling mechanism includes movable components that allow the secondary bag to be securely attached when needed and easily removed or concealed when not needed, thus adapting to different aesthetic requirements while maintaining reliable attachment during use.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent extracts the coupling mechanism from the permanent structure of the primary bag, making it a separate, removable component. This extraction allows the coupler to be taken out or concealed when not in use, preserving the refined appearance of the suitcase. The coupling system can be stored in a dedicated compartment or attached in a way that minimizes visual impact when the secondary bag is not being used.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4706444A1Luggage system
Publication Date: 2026.03.11 KOPF ENTERPRISES LLC
  • EP4706444A1 patent drawingFigure 1
  • EP4706444A1 patent drawingFigure 2
  • EP4706444A1 patent drawingFigure 3A

AI summary

A suitcase (100) may include a main body (104) having an opening (340) therein. The suitcase (100) may further include a base (304) disposed in the opening (340). The suitcase (100) may further include a coupler (302) configured to selectively engage with a portion of a secondary bag, the coupler (302) being configured to be received in the opening (340). The suitcase (100) may further include a strap (310) extending from the coupler (302). The suitcase (100) may further include a lock-fastener (306) supported by the main body (104) and configured to allow the strap (310) to be adjusted to increase or decrease a length of the strap (310) between the coupler (30) and the lock-fastener (306).