Ski Core with Corrugated Cardboard Beams

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Solution Overview

Problem

Conventional cross-country skis face challenges in achieving a balance between weight, mechanical strength, and cost-effectiveness, particularly in the manufacturing process, which is complex due to the use of multiple materials and structures.

Innovation Solution

A cross-country ski core design utilizing longitudinal beams made from corrugated cardboard with parallel corrugations and lateral edges, combined with narrower, more rigid longitudinal stiffening elements, allows for a lightweight and cost-effective structure that maintains mechanical strength by segmenting the core width and using a compact structure that adapts to variable dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If honeycomb material is used for the core, then resistance to crushing is improved, but manufacturing complexity increases due to assembly of separate parts

Engineering Contradiction:
Improveresistance to crushingVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The core is divided into multiple longitudinal beams made of corrugated cardboard, separated by longitudinal stiffening elements. This segmentation allows each component to be manufactured independently and then assembled, simplifying the overall manufacturing process while maintaining structural integrity and crush resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines corrugated cardboard with longitudinal stiffening elements to create a composite core structure. This composite approach leverages the lightweight properties of corrugated cardboard while adding rigid stiffening elements to enhance mechanical strength and resistance to crushing forces.

Inventive Principle:
Principle #40Composite materials

2Strength

If multiple materials are used in the core, then mechanical strength is improved, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing cost and process simplicity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The core structure is segmented into standardized longitudinal beams and stiffening elements that can be manufactured using simple, cost-effective processes. Each segment is produced independently and then assembled, reducing manufacturing complexity while maintaining mechanical strength through the combined material system.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the core structure is made to adapt to variable ski dimensions, then adaptability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveadaptability to variable dimensionsVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The core is constructed from multiple standardized longitudinal beams and stiffening elements that can be selectively arranged and configured. This modular segmentation enables the same basic components to be adapted to different ski lengths and sidecut profiles by varying the number, position, and dimensions of the beams and stiffening elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The longitudinal beams and stiffening elements can be locally adjusted in width, spacing, and positioning to match the specific dimensional requirements of different ski designs. This local customization allows the core structure to adapt to variable ski dimensions while maintaining manufacturing simplicity through standardized component production.

Inventive Principle:
Principle #3Local quality

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

This design results in a ski that is lightweight, cost-effective, and easy to manufacture, with improved resistance to crushing forces, while maintaining mechanical strength and adaptability to variable ski dimensions.

Implementation Method 1

the corrugations of the cardboard are parallel and have ridges oriented perpendicularly to the underside of the core. In this way, the vertically applied forces are supported by the generatrices of the corrugated cardboard sheet, with good crush resistance

Methodology Applied
Scientific EffectCorrugation structure: Corrugation

Data Source

PatentEP3251730B1Ski with lightweight core
Publication Date: 2021.02.17 SKIS ROSSIGNOL SA VOIRON FR
  • EP3251730B1 patent drawingFigure 1~4
  • EP3251730B1 patent drawingFigure 5~6
  • EP3251730B1 patent drawingFigure 7

AI summary

Ski (1), comprising: • a core (10) including longitudinal beams (13, 14, 15) made of corrugated cardboard, • side edges (20, 21) bordering the core (10), characterized in that it includes at least one longitudinal stiffening element (16, 17) extending over the entire height of the core (10), separating two longitudinal beams (13, 14, 15) made of corrugated cardboard, in which the width 1 of the longitudinal stiffening element (16, 17) measured transversely at the midpoint of the boot is less than that of the longitudinal beams made of corrugated cardboard.