Thermoplastic Ski Pole Strap for Power Transfer and Hand Comfort

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Solution Overview

Problem

Existing cross-country ski pole straps lose power efficiency due to deformation of soft tissue in the hands during pole strokes, leading to discomfort and increased risk of blisters and calluses.

Innovation Solution

A ski pole strap with a hand support portion made of thermoplastic material, plastically shapeable at temperatures below 100°C, is designed to surround the ulnar border of the skier's hand, providing a surface density of at least 0.03 g/cm² and a flexural modulus of at least 50 MPa, allowing the material to conform to the individual hand shape and reduce tissue deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional ski pole strap materials are used, then the strap is flexible and comfortable, but power transfer efficiency is lost due to soft tissue deformation

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidhand comfort
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The patent applies parameter changes by utilizing the thermoplastic material's temperature-dependent properties. At molding temperature (above glass transition temperature), the material is soft and compliant for shaping. At service temperature (below glass transition temperature), the material becomes rigid to prevent tissue deformation and improve power transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating a customized fit that conforms specifically to the individual skier's hand shape. The thermoplastic material is molded to match the exact contours of the user's hand, providing localized support precisely where needed to minimize soft tissue deformation during poling strokes.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If thermoplastic material is added to improve power transfer, then power transfer efficiency increases, but the molding process becomes more complex

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidmolding process complexity
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The patent applies self-service by enabling the end-user to perform the molding process themselves. The simplified two-step method (heating in water, then shaping on hand) allows consumers to customize their own straps without requiring specialized equipment or professional assistance, significantly reducing manufacturing complexity while maintaining power transfer efficiency benefits.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If the thermoplastic material is made rigid to reduce tissue deformation, then power transfer improves, but the material becomes difficult to shape to individual hand contours

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidhand contour conformity
Core Design Contradiction:
Loss of energyVSShape

Solution Approach 1:

The patent applies parameter changes by utilizing the thermoplastic material's temperature-dependent properties. At molding temperature (above glass transition temperature), the material is soft and compliant for shaping. At service temperature (below glass transition temperature), the material becomes rigid to prevent tissue deformation and improve power transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

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 solution significantly enhances power transfer efficiency and reduces soft tissue deformation, minimizing blisters and calluses, thereby improving comfort and performance during double poling.

Implementation Method 1

a sufficient amount of thermoplastic material that is plastically shapeable at a temperature that allows the skier to mold at least a relevant sub-portion of the hand support portion to follow the individual shape of his/her hand

Methodology Applied
Scientific EffectThermoplastic deformation: Plasticity

Implementation Method 2

the relevant sub-portion of the hand support portion has been molded to follow the individual shape of the skier's hand when the hand holds a ski pole, and when the relevant sub-portion of the hand support portion has been cooled down to room temperature

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP4585280A1Ski pole strap for improved power transfer, and ski pole
Publication Date: 2025.07.16 INVIVOPOWER AB
  • EP4585280A1 patent drawingFigure 1~2
  • EP4585280A1 patent drawingFigure 3A~3B
  • EP4585280A1 patent drawingFigure 4A~4B

AI summary

A ski pole strap (1) for transfer of power from a skier's hand (29) to a ski pole (27) when a pole stroke is performed in cross-country skiing, the ski pole strap (1) comprising an attachment portion (3) configured to attach the ski pole strap (1) to the ski pole (27); and a hand support portion (5) for supporting the hand (29) of the skier, the hand support portion (5) comprising at least 0.03 g/cm2 of a thermoplastic material arranged at least in a region of the hand support portion configured to surround an ulnar border (31) of the skier's hand (29), when the ski pole strap (1) is in use, the thermoplastic material being plastically shapeable at a temperature below 100°C and having a flexural modulus of at least 50 MPa at 20°C.