Ski Boot Reel Closure for Precise Incremental Fit Adjustment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional ski boot closure devices often struggle to achieve a balance between comfort and fit due to the use of rigid materials, and they typically tighten in large increments, making it difficult to achieve a proper fit.

Innovation Solution

A reel-based closure device with a tightening system that includes a reel mechanism, guides, and a tension member, allowing for incremental and easy adjustment of the ski boot fit, using a gear mechanism to amplify torque and facilitate smooth tightening and loosening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional closure devices are used to tighten ski boots, then the boot can be closed, but the tightening occurs in relatively large increments making it difficult to achieve proper fit balance

Engineering Contradiction:
Improveease of adjustmentVSAvoidfit precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The closure device transitions from static buckles to a dynamic reel-based system with a tension member that can be continuously adjusted. The reel mechanism allows the tension member to be wound or unwound in small increments, enabling dynamic adjustment of the boot fit to achieve precise balance between comfort and performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the adjustment parameter from discrete buckle notches to continuous tension member length. By varying the amount of tension member wound on the reel, the closure force can be precisely controlled, allowing fine-tuning of the fit rather than being constrained to large incremental changes.

Inventive Principle:
Principle #35Parameter changes

2Strength

If rigid polymer materials are used for exterior shells, then the boot provides structural support, but the boot becomes difficult to close and uncomfortable to wear

Engineering Contradiction:
Improvestructural supportVSAvoidease of closure
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent introduces a flexible tension member (such as a webbing strap) that works in conjunction with the rigid exterior shell. The flexible tension member can be easily manipulated and adjusted, providing ease of closure while the rigid shell maintains structural support. The flexible member conforms to the leg shape better than rigid buckles.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The tension member acts as an intermediary between the user's closing action and the rigid shell. Instead of directly manipulating rigid buckles or laces, the user operates the reel mechanism which then applies controlled tension through the flexible member to the rigid shell, making the closure process easier and more precise.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If traditional buckles are used for closure, then the structure is simple, but the adjustment increments are large and precision is limited

Engineering Contradiction:
Improvestructural simplicityVSAvoidfit adjustment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The closure system is segmented into distinct functional components: the reel mechanism, the tension member, and the attachment points. This segmentation allows each component to be optimized for its specific function - the reel provides precise rotational control, the tension member provides flexible force transmission, and the attachments provide secure connection - while working together to achieve precise fit adjustment.

Inventive Principle:
Principle #1Segmentation

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 reel-based closure device provides easy and precise adjustment of ski boot fit, enhancing comfort and fit balance by allowing for small incremental adjustments, replacing traditional buckles, and supporting high torque outputs.

Implementation Method 1

The closure device may include a gear mechanism that increases an input torque to generate a high torque output

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

A spool may be rotatably positioned within the housing. A tension member may be frictionally engaged about a peripheral surface of the spool

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4255247B1Reel based closure device
Publication Date: 2026.03.11 BOA TECHNOLOGY INC
  • EP4255247B1 patent drawingFigure 1
  • EP4255247B1 patent drawingFigure 2
  • EP4255247B1 patent drawingFigure 3A~3B

AI summary

A boot, such as a ski boot, may include a lower portion or shell that is configured to accommodate a foot and an upper portion or cuff that extends upward from the lower portion and that is configured to accommodate a lower leg of a wearer. The boot may also include a tightening system that is coupled with the lower portion of the boot in order to close and tighten the lower portion about the foot. The tightening system includes a reel based closure device and a tension member that is operably coupled with the reel based closure device so that an operation of the reel based closure device effects tensioning of the tension member. The tightening system also includes a plurality of guide members that route or direct the tension member along a path and a terminal member that is fixedly coupled with the tension member.