Modular Shoe Last Structure for Custom Foot Shape Fitting

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Solution Overview

Problem

Conventional last structures for custom-order shoes have complex position adjusting mechanisms, requiring high production costs and time, and cannot fully adapt to individual foot shapes due to limitations in adjusting the longitudinal width and instep height, leading to gaps and steps in the outer surface.

Innovation Solution

A last design comprising a standard body and additional parts that can be fixed to change the outer surface shape, allowing adaptation to various foot models using a single last body and multiple additional parts, reducing production time and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a position adjusting mechanism is used to change the shape of the last, then the adaptability to different foot shapes is improved, but the device complexity and production cost increase significantly

Engineering Contradiction:

Improveadaptability to foot shapeVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The last is divided into a standard last body and separate additional parts (first additional part, second additional part, third additional part) that can be independently selected and attached. Each additional part corresponds to a specific foot model type, allowing the last to be segmented into modular components that can be reconfigured for different foot shapes without complex adjustment mechanisms.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A single standard last body is designed to serve multiple functions by accommodating different additional parts. The standard last body remains unchanged while various additional parts (with different thicknesses and shapes) are attached to it, enabling one base structure to adapt to multiple foot model types (A, B, C, D, E, 2E, 3E, 4E, F, G) without requiring multiple complete last structures or complex adjustment mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a position adjusting mechanism is used to adjust the last shape, then the adaptability to different foot shapes is improved, but the production time and labor increase

Engineering Contradiction:

Improveadaptability to foot shapeVSAvoidproduction efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

Additional parts are pre-manufactured with specific thicknesses and shapes corresponding to different foot model types before being attached to the standard last body. This preliminary preparation of standardized components eliminates the need for complex real-time adjustments during last production, significantly reducing production time and labor while maintaining high adaptability to different foot shapes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The last production process is segmented into independent steps: preparing the standard last body, selecting the appropriate additional part based on foot model type, and attaching them together. This segmentation allows for parallel production of standard last bodies and additional parts, improving overall production efficiency while maintaining the ability to customize for different foot shapes.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If position change portions are moved away from the common portion to increase dimensions, then the adaptability to different foot sizes is improved, but gaps are generated between parts

Engineering Contradiction:

Improveadaptability to foot sizeVSAvoidouter surface continuity

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The additional parts serve as intermediary elements that fill the gap between the standard last body and the required outer surface shape. By attaching these additional parts (which have varying thicknesses) to different portions of the standard last body, the invention achieves continuous outer surface geometry without gaps, while simultaneously adapting to different foot sizes and shapes.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Adaptability or versatility

If position change portions are moved away from the common portion to increase dimensions, then the adaptability to different foot sizes is improved, but steps are generated in the outer surface shape

Engineering Contradiction:

Improveadaptability to foot sizeVSAvoidouter surface smoothness

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The additional parts are designed with locally varying thicknesses that precisely match the required dimensional adjustments for different foot model types. By applying different thicknesses of additional material to specific locations on the standard last body, the invention achieves smooth, continuous outer surface geometry that accurately reflects the target foot shape, eliminating steps while maintaining adaptability to different foot sizes.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260068997A1last

Publication Date: 2026.03.12 MIZUNO CORPORATION

AI summary

It is enabled to easily and inexpensively provide a last in accordance with a foot shape and a request of each customer.A last L includes a last body 10 having an outer surface shape corresponding to a predetermined standard foot model and an additional part 20 that changes the outer surface shape of the last L to a different shape from a shape of the standard foot model by fixing the additional part 20 to the last 10.