Ski Boot Composite Shell Segmentation for Weight Reduction

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Solution Overview

Problem

Current ski-boots for alpine skiing and telemark struggle to further reduce weight without compromising the flexibility of the shell, which is essential for safe and proper performance in these sports.

Innovation Solution

The ski-boot design incorporates a composite material bootleg with superimposed layers of glass, carbon, or aramidic fibers embedded in a thermosetting resin, combined with a front half-shell made of non-reinforced plastic polymer, allowing for elastic deformation and weight reduction without jeopardizing flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the bootleg is made of composite material (glass/carbon fibres in epoxy resin), then weight is reduced and structural stiffness is increased, but shell flexibility is compromised

Engineering Contradiction:
Improveoverall weight of ski-bootVSAvoidshell flexibility
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The shell is divided into two distinct parts: a front half-shell made of flexible plastic polymer material and a rear half-shell made of rigid composite material. This segmentation allows each part to have optimized properties - the front maintains flexibility for proper movement while the rear provides stiffness for structural support, resolving the contradiction between weight reduction and flexibility preservation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are applied to different regions of the shell based on local functional requirements. The front half-shell uses plastic polymer material where flexibility is needed for natural foot movement, while the rear half-shell uses composite material where stiffness and weight reduction are priorities. This local differentiation resolves the contradiction by applying material properties where they are most needed.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the entire shell is made of composite material, then weight is reduced and structural stiffness is increased, but flexibility essential for safe skiing is lost

Engineering Contradiction:
Improveoverall weight of ski-bootVSAvoidsafe skiing performance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The shell is segmented into front and rear halves with different material compositions. The front half-shell made of plastic polymer maintains the flexibility necessary for safe skiing and proper foot movement, while the rear half-shell uses composite material for weight reduction. This segmentation ensures safety is not compromised while achieving weight reduction goals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Material selection is localized to match functional requirements - the front half-shell uses flexible plastic material where reliability and safety depend on flexibility, while the rear uses stiff composite material where weight reduction is the priority. This local quality approach ensures safety requirements are met in critical areas.

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 achieves a significant reduction in overall weight while maintaining essential flexibility, preventing mechanical stress concentration and potential material failure, ensuring safe and effective performance in alpine skiing and telemark activities.

Implementation Method 1

a rigid bootleg made of plastic material, which is shaped so as to wrap round the ankle... some manufacturers of ski-boots have marketed ski-boots for alpine skiing or telemark in which the bootleg is integrally made of a composite material basically constituted by one or more superimposed layers of glass fibres and/or carbon fibres appropriately intertwined and/or superimposed on one another and embedded in a matrix of epoxy resin of a thermosetting type

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

the top part of the shell of telemark ski-boots is also provided with a programmed deformation bellows, which extends astride of the metatarsal region of the foot so to allow the rear part of the shell to bend forwards with respect to the toe of the shell

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2227974B1Ski boot
Publication Date: 2012.05.02 CALZATURIFICIO S C A R P A
  • EP2227974B1 patent drawingFigure 1
  • EP2227974B1 patent drawingFigure 2
  • EP2227974B1 patent drawingFigure 3

AI summary

A ski-boot (1) comprising an outer rigid shell (2), which is shaped so as to receive the user's foot, and a rigid bootleg (5) which is shaped so as to wrap round the user's ankle and is hinged on the top part of the shell (2) in order to be able to swing about a first reference axis (A) that locally substantially coincides with the articulation axis of the user's ankle; the shell (2) being made up of a front half-shell (9) and a rear half-shell (10) rigidly fixed to one another; the front half-shell (9) having a substantially ogival shape for covering the user's toe substantially up to the beginning of the plantar arch area of the foot and being made of at least one plastic polymer by injection moulding; the rear half-shell (10) being designed to completely cover the remaining part of the foot, starting substantially from the plantar arch area of the foot and being made of a composite material containing fibres embedded in a resin matrix.