Shoe Last Assembly via Interlocking Plate Shapes

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Solution Overview

Problem

Existing shoe last manufacturing methods face challenges in easily and reliably fixing plate-shaped parts together to form a precise shape conforming to a wearer's foot, which is essential for creating well-fitted shoes.

Innovation Solution

A shoe last is designed using detachable plate-shaped parts with specific cutout and protruding shapes for assembly, allowing for easy and secure engagement of these parts to form a forming surface for the shoe upper, facilitating efficient assembly and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If plate-shaped parts are assembled to form a last, then the last can be easily fabricated and adapted to different foot shapes, but the reliability of fixing the parts together becomes problematic

Engineering Contradiction:
Improveadaptability to different foot shapesVSAvoidreliability of part fixation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The plate-shaped parts are designed with receiving portions that nest over adjacent plates, creating an interlocking assembly structure. This nesting configuration allows the parts to be securely fixed together while maintaining adaptability to different foot shapes, as the modular design can be adjusted by reconfiguring the nested plates.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If plate-shaped parts are used to form a last, then manufacturing flexibility is improved, but the assembly reliability and mechanical strength deteriorate

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidassembly mechanical strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Receiving portions and engaging portions are pre-formed during the plate manufacturing process, so that when plates are assembled, the engagement features are already in place. This preliminary action ensures strong mechanical connections without requiring additional assembly steps, thereby maintaining both manufacturing flexibility and assembly strength.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The last is divided into multiple plate-shaped parts that can be manufactured separately using standard fabrication processes, then assembled using the receiving and engaging portions. This segmentation allows each plate to be manufactured with optimal strength characteristics while the overall assembly maintains flexibility.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple last forming parts are assembled together, then adaptability to foot shapes is improved, but the assembly process becomes complex

Engineering Contradiction:
Improveconformity to foot shapeVSAvoidassembly process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The last is segmented into multiple plate-shaped parts, each corresponding to a specific region of the foot. This segmentation allows the assembly to conform to the complex geometry of the foot while keeping each individual plate simple in design and easy to manufacture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The plates are designed with receiving portions that nest over adjacent plates in a systematic sequence. This nesting approach provides a clear assembly procedure where each plate is placed in a specific position relative to its neighbors, reducing assembly complexity despite the number of parts.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4169411B1last
Publication Date: 2024.11.06 ASICS CORP
  • EP4169411B1 patent drawingFigure 1
  • EP4169411B1 patent drawingFigure 2
  • EP4169411B1 patent drawingFigure 3

AI summary

A last (1A) includes a first part (110) having a first plate-shaped portion (111) and a second part (120) having a second part-side receiving portion (122) having a cutout shape. When the first plate-shaped portion (111) is received in the second part-side receiving portion (122), the first part (110) and the second part (120) are assembled. The second part (120) includes a second part-side engaging portion (123) having a protruding shape on an inner side surface in a portion defining the second part-side receiving portion (122), and the first plate-shaped portion (111) has a main surface with a first part-side to-be-engaged portion (114) having a through hole shape or a recessed shape. When the first plate-shaped portion (111) is inserted into the second part-side receiving portion (122), the first plate-shaped portion (111) is fitted into the second part-side receiving portion (122), and the first part-side to-be-engaged portion (114) is engaged by the second part-side engaging portion (123).