Independent Reel Closure Layout for Differential Ski Boot Fit

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Solution Overview

Problem

Ski boots made of rigid materials often struggle with achieving a balance between comfort and fit due to difficulty in precise adjustment, as conventional closure devices tighten in large increments.

Innovation Solution

The implementation of multiple reel-based closure systems, each with independent tension members and guide members, allows for precise and incremental tightening of different boot portions, including the lower shell, upper cuff, and optional liner, enabling differential and customizable fit adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

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 precise adjustment difficult

Engineering Contradiction:
Improvetightening adjustment precisionVSAvoidclosure device structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The closure system is divided into multiple independent tightening systems, each responsible for a specific region of the boot (toe box, instep, ankle, cuff). Each system includes its own reel-based closure device and tension member, allowing independent adjustment of each region with fine incremental control rather than large uniform steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reel-based closure devices provide dynamic, continuous adjustment capability through rotational movement, enabling users to make precise incremental adjustments to tension. The guide members with movable components allow the tension members to be routed dynamically around the boot structure, facilitating smooth tension changes.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple independent tightening systems are implemented, then precise and differential adjustment of different boot portions is enabled, but the device complexity increases

Engineering Contradiction:
Improvecustomizable fit adjustmentVSAvoidnumber of tightening systems
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The boot closure system is segmented into multiple independent tightening systems, each targeting a specific anatomical region (toe box, instep, ankle, cuff). This segmentation allows each system to be optimized for its specific function while maintaining overall system manageability through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reel-based closure device design serves as a universal component that can be replicated across multiple tightening systems. Each system uses the same fundamental reel mechanism and tension member configuration, providing multi-functionality while maintaining design consistency and reducing overall complexity through standardization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If reel based closure devices with guide members are used, then fine-tuned incremental tightening is achieved, but the manufacturing complexity increases

Engineering Contradiction:
Improvefit adjustment precisionVSAvoidclosure system assembly
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The guide members are pre-configured with specific geometries and routing paths that guide the tension members through predetermined routes around the boot structure. This preliminary configuration of guide member positions and orientations simplifies the assembly process by eliminating the need for complex field adjustments, while still enabling precise tension control during use.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3917350B1Reel based closure devices for tightening a ski boot
Publication Date: 2025.12.03 BOA TECHNOLOGY INC
  • EP3917350B1 patent drawingFigure 1~2
  • EP3917350B1 patent drawingFigure 3~4
  • EP3917350B1 patent drawingFigure 5~6

AI summary

A differentially tightenable ski boot includes a lower shell and an upper cuff that is pivotally coupled with the lower shell. The ski boot includes a first tightening system that is coupled with the lower shell and a second tightening system that is coupled with the upper cuff. Each tightening system includes a reel based closure device, a tension member that is operably coupled with the reel based closure device, and at least one guide member that routes or directs the tension member along a path about the lower shell or upper cuff. The first tightening system and the second tightening system are operable independently of each other to independently and differentially tightening the lower shell and the upper cuff.