Thermoformed Plastic Helmet Shell With Composite Fiber Layer

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Solution Overview

Problem

Conventional safety helmet manufacturing methods face challenges such as requiring skilled operators for gluing patterned layers or fabric materials onto curved surfaces, leading to wrinkles, creases, and non-uniform appearances, as well as being labor-intensive and time-consuming, with difficulties in aligning edges and controlling quality.

Innovation Solution

A method involving a highly hydrophilic fiber layer laminated onto a thin sheet material, which is then thermoformed and stamped to create a helmet-shaped shell with the fiber layer in a tensed state, allowing for smooth attachment and printing of patterns, and filled with a foaming material for added reinforcement and elasticity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If patterned layers or fabric materials are glued onto the curved outer surface of the helmet shell, then colors or patterns can be shown on the outer surface, but wrinkles and creases occur on the planar patterned layers or fabric materials

Engineering Contradiction:

Improveease of colorization and patterningVSAvoidsurface smoothness and pattern alignment

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patterned layers are pre-stretched and pre-formed to match the curved profile of the helmet shell before gluing. This preliminary action ensures that the patterns are already adapted to the curved surface geometry, preventing wrinkles and creases during the gluing process while maintaining manufacturing ease

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The physical state of the patterned layers is changed by stretching and heating them to make them more pliable and adaptable to the curved surface. This parameter change allows the planar materials to conform to the three-dimensional curved profile without creating surface defects

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If multiple pieces of patterned layers are applied to the helmet shell, then colors and patterns can be shown, but the process requires skilled operators and increases manufacturing time

Engineering Contradiction:

Improveease of colorizationVSAvoidmanufacturing efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

Multiple separate gluing operations for different patterned layers are merged into a single integrated process. The helmet shell is formed with all patterned layers already attached during the thermoforming process, eliminating sequential gluing steps and reducing the need for skilled operators while improving productivity

Inventive Principle:

Principle #5Merging (Combining)

3Weight of moving object

If the helmet shell is made thinner to reduce weight, then the helmet becomes lighter, but the structural strength and impact resistance may be compromised

Engineering Contradiction:

Improvehelmet weightVSAvoidimpact resistance

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The helmet shell uses composite construction combining the plastic shell with fabric materials or foam filling integrated into the shell structure. This composite approach maintains impact resistance and structural strength while keeping the overall weight low, as the distributed reinforcement provides strength without requiring thick solid plastic

Inventive Principle:

Principle #40Composite materials

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

This approach simplifies the manufacturing process, reduces labor and time, ensures smooth pattern alignment, and enhances the helmet's structural strength and elasticity, while allowing for colorful patterns and reduced weight, effectively addressing the limitations of conventional methods.

Implementation Method 1

a thin helmet shell including a fiber layer with good hydrophilicity, i.e. a highly hydrophilic fabric layer

Methodology Applied

Scientific EffectHydrophilicity: Hydrophile

Implementation Method 2

laminated to a thin and flat sheet of plastic material to form a thin sheet preform

Methodology Applied

Scientific EffectLamination: Lamination

Implementation Method 3

the preform undergoes thermoforming and stamping to provide a helmet-shaped shell

Methodology Applied

Scientific EffectThermoforming: Heat Treatment

Implementation Method 4

the fiber layer is composited with the shell to form a smooth and fitly attached outer surface structure

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Implementation Method 5

impact-resistant filler made of a thermal foaming material

Methodology Applied

Scientific EffectThermal foaming: Foam

Data Source

PatentUS20240306755A1Optimized plastic helmet shell structure

Publication Date: 2024.09.19 HO CHANG HSIEN

AI summary

An optimized plastic helmet shell structure includes a preform made of a composite material produced from at least one fiber layer attached to an outer surface of a thin sheet shell consisting of at least one piece of thin sheet plastic material. The preform is hot formed in a forming module to form a helmet-shaped shell assembly. During the hot forming, the thin sheet shell has at least a part of its surface structure combined with or permeated into the fiber layer and the fiber layer is stretched on along the outer surface of the thin sheet shell into a tensed state. Therefore, the whole helmet-shaped shell assembly has reinforced but thin and light structure, and the fiber layer is smoothly and fitly attached to the outer surface of the shell assembly and can be colorized or printed with patterns.