Hard Shell Suitcase Collar Interlock for Stacking Stability

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Solution Overview

Problem

Existing shell cases, particularly hard shell cases, fail to securely stack on top of each other, especially when braking or accelerating, as they shift due to lack of effective coupling in the plane, leading to instability.

Innovation Solution

The shell cases feature a collar on each broad side that protrudes in height, with inner and outer edges of varying heights and identical angular positions, allowing for a locking mechanism that ensures secure stacking regardless of alignment, with the collar designed to interlock seamlessly across the entire length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If shell cases are stacked on top of each other without a locking mechanism, then stacking is simple and device complexity is low, but the cases shift position during braking or acceleration, resulting in poor stability

Engineering Contradiction:
Improvestacking stabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The collar features an asymmetric design with different inner and outer edges at varying heights. The outer edge is higher than the inner edge on one broad side, while the opposite broad side has the inner edge higher than the outer edge. This asymmetric configuration enables the collars of adjacent cases to interlock securely, preventing lateral shifting during transport while maintaining structural simplicity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The solution transitions from two-dimensional flat case surfaces to three-dimensional protruding collars with vertical height variation. The collars extend vertically beyond the broad sides of the cases, creating a third dimension for interlocking. This dimensional addition provides mechanical coupling that prevents shifting without requiring complex multi-component locking systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If collars are designed to interlock securely, then positioning precision improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecollar alignment precisionVSAvoidcollar manufacturing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The collar is integrated as a single monolithic structure with the case body rather than being a separate component. The collar protrudes directly from the case's broad sides as part of the same molded piece, combining the case structure and locking feature into one manufacturing operation. This merging reduces assembly steps and maintains precision without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If the collar extends vertically beyond the broad side, then the locking strength increases, but the device complexity increases

Engineering Contradiction:
Improvelocking strengthVSAvoidcollar structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The collar structure is segmented into distinct functional zones: the horizontal protruding portion that provides the locking interface, and the vertical extension that provides structural support and engagement depth. This segmentation allows each zone to be optimized for its specific function while maintaining overall structural efficiency and avoiding unnecessary complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3135150B1Luggage case, in particular hard case luggage
Publication Date: 2020.08.05 W AG FUNKTION DESIGN
  • EP3135150B1 patent drawingFigure 1

AI summary

The invention relates to a hard-shell suitcase (1), in particular a hard-shell suitcase, wherein the hard-shell suitcase (1) has a first and a second broad side (7), wherein, for stacking hard-shell suitcases on their broad sides (7), each hard-shell suitcase (1) has on at least one broad side (7) a device for locking the adjacent hard-shell suitcase (1) in the plane of the broad side (7).