Vehicle Roof Box Load Stop Energy Absorption

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Solution Overview

Problem

Existing roof boxes face challenges in preventing loads from escaping during vehicle crashes or sudden retardation, particularly with heavy sports equipment like skies and snowboards, due to insufficient structural reinforcement and energy absorption.

Innovation Solution

A roof box design featuring a load stop with a floor portion adhered to the base portion, which disperses kinetic energy through a large adhered surface area, eliminating structural weak points like screw holes and providing additional strength by adhering the load stop to the periphery wall, using a more rigid thermoplastic material for the load stop and a different thermoplastic material for the base portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If objects are secured using cargo nets or straps, then objects can be retained in the roof box, but objects can still be forced through the roof box wall during a crash due to inertia

Engineering Contradiction:
Improveobject retentionVSAvoidroof box wall strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent incorporates an absorbing member with a bow-shaped form that acts as a pre-positioned energy absorption system. This member is designed to deform and absorb kinetic energy during crashes or sudden retardation, preventing objects from forcing their way through the roof box wall. The cushioning effect is built into the structure beforehand, addressing the limitation of passive cargo nets and straps.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the absorbing member is attached to the side walls using screws, then the member can be secured to the base portion, but the screw holes create structural weak points that reduce the base portion strength

Engineering Contradiction:
Improveabsorbing member attachmentVSAvoidbase portion strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent removes the screws and screw holes from the attachment system. Instead of penetrating the base portion with fasteners that create weak points, the absorbing member is attached using an alternative method that does not compromise the structural integrity of the molded base portion. This extraction of the problematic fastening elements eliminates the structural weak points while maintaining secure attachment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent integrates the attachment function directly into the molded structure of the base portion. The absorbing member is combined with the base portion through a unified attachment system that is part of the molding process, eliminating the need for separate fasteners and creating a seamless structural integration that maintains strength throughout the base portion.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a load stop is added to prevent objects from escaping during crashes, then safety is improved, but the device complexity increases

Engineering Contradiction:
Improvecrash safetyVSAvoidroof box structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load stop structure serves multiple functions simultaneously: it acts as a physical barrier to prevent object escape, provides energy absorption capability, and integrates with the existing base portion structure. By combining these functions into a single multi-functional element, the patent improves crash safety without proportionally increasing device complexity.

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

Solution Approach 2:

The load stop is designed to nest within or integrate with the existing roof box structure, utilizing the available space and structural elements. This nested integration allows the load stop to function effectively while maintaining a compact overall design and minimizing the increase in device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 design effectively prevents objects from penetrating the roof box during collisions by efficiently transferring kinetic energy, enhancing the roof box's stability and safety without compromising its structure.

Implementation Method 1

The floor portion is adhered to the load receiving area of the base portion... the whole adhered surface transfers force to the base portion of the roof box

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2705985B1Roof box for a vehicle
Publication Date: 2015.04.29 THULE SWEDEN AB
  • EP2705985B1 patent drawingFigure 1
  • EP2705985B1 patent drawingFigure 2
  • EP2705985B1 patent drawingFigure 3

AI summary

A roof box (1) for a vehicle (3), the roof box (1) comprises a base portion (10) with a load receiving area (20). The base portion (10) is adapted to be positioned in the proximity of a roof (2) of a vehicle (3), a closable lid (11) or net, adapted to retain cargo on the load receiving area (20) of the base portion (10). The base portion (10) of the roof box (1) comprises a load stop (30). The load stop (30) of the base portion (10) is effectively preventing, or at least reducing the risk or, cargo, such as skies or the like, from penetrating through the roof box in case of a collision or crash,