Rigid Ski Boot Shell with Localized Heat-Shaping Zones

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Solution Overview

Problem

Current ski boots face challenges in adapting to the complex shape of individual feet without compromising rigidity or altering the external appearance, as existing methods for modifying volume and shape are limited by deformation techniques that require high temperatures and heavy tools, or result in loss of rigidity and aesthetic changes.

Innovation Solution

Incorporating an additive with a low melting point, such as caprolactone-based polymers, into the rigid plastic shell to lower the softening temperature of specific portions, allowing for localized deformation without significant loss of rigidity or aesthetic alteration, and using a heating machine with opposing hot air nozzles to heat these areas for shaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the shell is deformed by local heating to high temperature using heavy tools, then the shape of the shell can be adapted to the foot, but the external appearance is degraded and the process becomes complex

Engineering Contradiction:
Improveshape adaptation to footVSAvoidmanufacturing complexity and appearance degradation
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The shell is constructed with portions of different stiffness, where sensitive zones (malleoli, metatarsals) have more flexible portions made of thermoplastic material, while other areas maintain rigid structure. This allows localized deformation in specific zones without affecting the overall shell integrity or external appearance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shell material's temperature parameter is utilized by heating the thermoplastic portions to above their softening point (around 100°C), transforming them from rigid to pliable state for deformation, then cooling to restore rigidity. This temporary parameter change enables shape adaptation without permanent material property alteration.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the liner is deformed to adapt to foot volume, then the precision of fit is improved, but the field of application is restricted by wall thickness and interior volume

Engineering Contradiction:
Improvefit precisionVSAvoidapplication field limitation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Instead of uniformly deforming the entire liner, the invention applies deformation locally to specific portions of the shell that contact sensitive foot areas. This targeted approach achieves precise fit where needed while preserving the structural integrity and volume of the overall boot.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shell combines rigid plastic base material with thermoplastic material portions, creating a composite structure that provides both overall rigidity and localized flexibility. This composite construction enables precise adaptation without compromising the boot's structural requirements.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the shell uses portions of different stiffness for comfort, then the comfort in sensitive zones is improved, but the shell structure becomes hybrid with different materials and appearances

Engineering Contradiction:
Improvecomfort in sensitive zonesVSAvoidappearance uniformity
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The shell incorporates portions of different stiffness specifically in sensitive zones (malleoli, metatarsals) while maintaining uniform appearance. The thermoplastic material portions are visually integrated with the rigid shell, providing localized comfort without creating obvious visual discrepancies or hybrid material appearance.

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

Enables precise adaptation of the shoe to the foot's shape with improved comfort and precision, maintaining the shoe's rigidity and appearance, and allowing for repeated deformation without compromising mechanical properties or aesthetics.

Implementation Method 1

the material of the shell contains an additive having a melting temperature below 100°C

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

lower the softening temperature of specific portions, allowing for localized deformation without significant loss of rigidity

Methodology Applied
Scientific EffectSoftening: Heat Treatment

Implementation Method 3

using a heating machine with opposing hot air nozzles to heat these areas for shaping

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

After this phase of deformation, the material regains its original rigidity with the cooling of the portions with additive

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP1872678B1Rigid-shell shoe
Publication Date: 2015.07.22 SALOMON SA
  • EP1872678B1 patent drawingFigure 1~2
  • EP1872678B1 patent drawingFigure 3
  • EP1872678B1 patent drawingFigure 4~7

AI summary

The shoe (10) has a shell (11) made of rigid material, whose softening point is greater than 170 degree Celsius. An additive with a melting temperature less than 100 degree Celsius is mixed to the shell`s material in local portions of the shell with a proportion comprised between 10 and 25 percentages. The portions are formed by inserts that are made of material having rigidity same as that of the material of the shell. An independent claim is also included for a heating machine comprising a support.