Footwear Sole Insert with Rigid Rear Protection and Flexible Forefoot

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Solution Overview

Problem

Existing safety footwear fails to adequately combine anti-puncture properties with flexibility and stability, while also lacking sufficient cushioning and comfort.

Innovation Solution

A footwear design incorporating a protective insert with a rigid rear element and flexible front element, made of specific materials, which includes a concave structure to enhance puncture resistance and stability, and is integrated into the sole through direct injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid anti-puncture layer is incorporated in the sole, then puncture resistance is improved, but flexibility and comfort deteriorate

Engineering Contradiction:
Improvepuncture resistanceVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The protective insert is divided into two distinct elements: a rigid rear element for puncture resistance and a flexible front element for comfort and flexibility. This segmentation allows each part to perform its specific function optimally without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the sole are given different properties: the heel area (rear element) is made rigid for puncture protection, while the forefoot area (front element) is made flexible for comfort and natural foot movement. This local differentiation resolves the contradiction between overall rigidity and flexibility.

Inventive Principle:
Principle #3Local quality

2Reliability

If a rigid protective insert is added to the sole, then puncture resistance is improved, but shoe weight increases

Engineering Contradiction:
Improvepuncture resistanceVSAvoidshoe weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

By segmenting the protective insert into rigid and flexible portions, only the necessary rigid material is used in the heel area where puncture risk is highest, rather than making the entire sole rigid. This reduces unnecessary weight while maintaining protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent specifies that the rigid rear element has a thickness between 1-5mm, optimizing the balance between protection and weight. The controlled thickness parameter ensures sufficient puncture resistance without excessive weight addition.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the rigid rear element is positioned close to the insole, then puncture resistance is improved, but cushioning comfort deteriorates

Engineering Contradiction:
Improvepuncture resistanceVSAvoidcushioning comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The rigid rear element is nested within the sole structure at an optimized position that balances protection and comfort. The element is positioned to provide puncture resistance while the surrounding sole material and controlled thickness (1-5mm) ensure adequate cushioning is maintained.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4408230B1Footwear with sole provided with a protective insert
Publication Date: 2025.11.05 BASE PROTECTION SRL
  • EP4408230B1 patent drawingFigure 1
  • EP4408230B1 patent drawingFigure 2
  • EP4408230B1 patent drawingFigure 3

AI summary

A footwear (100) is described comprising: an upper (2) associated with an insole (3) and a sole (1) associated with the upper (2). The footwear is characterized in that it further includes a protective insert (4) inserted in said sole (1) and comprising: a rear element puncture (5) resistant to made of a first rigid material including plastic material and extending in a first zone designed to face the rear foot and mid foot of the user of the footwear (100); a front element (6) resistant to puncture made of a second flexible material including textile laminate and extending into a second area intended to be facing the forefoot of the user of the footwear (100).