Waterproof LED Sole via Injection Molding

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Solution Overview

Problem

Existing children's shoes with LED-based luminous effects are unsafe and not waterproof, as the lighting device can be tampered with and exposed to moisture, posing health risks.

Innovation Solution

A shoe design featuring a vibration-sensitive LED lighting device enclosed in a transparent, pressure-resistant protective enclosure embedded within the plastic sole, which is overmolded to ensure waterproofing and safety, with LEDs arranged for uniform light distribution and integrated into the sole during injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the LED-based lighting device is manually inserted in the sole of the shoe, then the luminous effect can be easily implemented, but the device becomes easily reachable and tampered with, creating safety hazards

Engineering Contradiction:
Improveease of implementationVSAvoidsafety
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The lighting device is extracted from the manual insertion process and instead integrated directly into the sole through injection molding. The lighting device is incorporated into the mold cavity, allowing it to be formed as an integral part of the sole structure rather than being separately inserted, thereby eliminating safety hazards while maintaining manufacturing efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The lighting device is merged with the sole structure through co-molding. The lighting device cavity is formed within the sole's mold cavity, and during injection molding, the lighting device material is injected to form a unified structure where the lighting device becomes an inherent part of the sole, making it inaccessible for tampering while preserving ease of manufacture

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If the lighting device is inserted under the insole in a molded seat, then the structure is simple, but the device is not perfectly waterproofed and exposed to moisture from perspiration or water infiltration

Engineering Contradiction:
Improvestructural simplicityVSAvoidwaterproofing
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The lighting device is combined with the sole structure through injection molding, creating a unified waterproof assembly. The lighting device is formed within the sole's mold cavity and the molding material encapsulates it completely, integrating the lighting device into the water-resistant sole structure rather than placing it in a separate vulnerable compartment

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sole material itself acts as a flexible waterproof shell that encapsulates the lighting device. During injection molding, the material forms a continuous protective barrier around the lighting device, providing waterproofing through the inherent water-resistant properties of the sole material while maintaining structural simplicity

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If the lighting device is manually inserted in the shoe, then installation is flexible, but noxious substances from batteries may propagate and contact the foot

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidexposure to noxious substances
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The battery compartment is extracted from accessible areas and integrated into the sole structure through injection molding. The battery cavity is formed within the molded sole, completely enclosing the battery and preventing exposure to the foot while maintaining installation flexibility through the molding process

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The battery compartment is merged with the sole structure during injection molding. The molding process creates an integrated assembly where the battery housing becomes part of the sole, providing complete enclosure that prevents noxious substance propagation while allowing flexible installation through the molding parameters

Inventive Principle:
Principle #5Merging (Combining)

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 solution provides a safe and waterproof luminous effect, enhancing user safety and durability while maintaining low manufacturing costs and simplicity.

Implementation Method 1

The lighting device 11 is of the LED type and operation depends on vibrations which, transmitted during walking, light the LEDs

Methodology Applied
Scientific EffectVibration-sensitive LED conversion: Vibration

Implementation Method 2

The protective enclosure 14 is made of transparent plastic material and can be replaced equivalently with a container having the same characteristics

Methodology Applied
Scientific EffectPressure resistance:

Implementation Method 3

the sole part 12 is advantageously overmolded on the lighting device 11 enclosed in the protective enclosure 14

Methodology Applied
Scientific EffectInjection molding adhesion: Adhesive

Data Source

PatentEP2873338B1Shoe with luminous effect
Publication Date: 2018.12.26 PERIN
  • EP2873338B1 patent drawingFigure 1~2
  • EP2873338B1 patent drawingFigure 3~4
  • EP2873338B1 patent drawingFigure 5

AI summary

A shoe (10) with luminous effect, which comprises a lighting device (11) which is enclosed in a protective sealing enclosure (14) that is embedded in the plastic material of a sole part (12) that is at least partially permeable to light and at least partially visible from the outside.