Bicycle Mudguard Back Injection Molding Decoration

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Solution Overview

Problem

Current bicycle mudguards made of polypropylene face challenges in achieving high-quality decorations or information due to poor pad printing quality and the need for post-processing, with adhesive foils often detaching or lacking a premium appearance.

Innovation Solution

A mudguard design featuring two downward-bent lateral projections forming a part-toroidal shape, integrated with a printed foil carrier made of the same polypropylene material, allowing for high-quality digital printing and a firm connection through back injection molding, eliminating the need for subsequent processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pad printing is used to decorate polypropylene mudguards, then the mudguard can be decorated with labels or text, but the printing quality is poor and requires post-processing

Engineering Contradiction:
Improveprinting qualityVSAvoidpost-processing requirement
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The printing is performed on the foil before injection molding, allowing the foil to be pre-decorated with high-quality digital printing. This preliminary action eliminates the need for subsequent printing operations on the finished mudguard, resolving the contradiction between printing quality and post-processing complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical pad printing process with digital printing on foil, which offers superior print quality. This substitution eliminates the inherent limitations of pad printing while maintaining the ability to decorate the mudguard effectively

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If adhesive foils are stuck onto the mudguard for decoration, then the mudguard can have labels or decorations, but the foils may detach and do not provide a high-quality appearance

Engineering Contradiction:
Improvedecoration qualityVSAvoidfoil attachment stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The foil and mudguard are merged into a single integrated component through back injection molding. The foil is placed in the mold cavity before injection, and the molten plastic encapsulates the foil, creating a permanent bond. This eliminates the detachment issue while maintaining high-quality appearance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite structure where the foil (one material) is permanently bonded to the polypropylene mudguard (another material) through the back injection process. This composite construction ensures both aesthetic quality and structural reliability

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If the mudguard is transported to a printer after injection molding for decoration, then the mudguard can be decorated, but the process requires high effort and additional steps

Engineering Contradiction:
Improvedecoration capabilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The decoration process is merged with the injection molding process itself. The foil is placed in the mold cavity before injection, and both the molding and decorating operations are completed in a single manufacturing cycle. This eliminates the need to transport the mudguard to a separate printing facility, significantly improving productivity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The foil is prepared and placed in the mold cavity in advance, before the injection molding begins. This preliminary preparation allows the decoration to be integrated into the molding process, eliminating subsequent transportation and post-processing steps

Inventive Principle:
Principle #10Preliminary action

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 solution ensures a durable, cost-effective production of fully decorated mudguards with a high-quality material connection and appearance, saving on post-processing costs and maintaining the integrity of the decorations.

Implementation Method 1

The mudguard body (1) is formed in a known manner by injection molding from a polypropylene (PP) material

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

Back injection molding results in a firm connection between the carrier means and the wheel protection body

Methodology Applied
Scientific EffectBack injection molding:

Data Source

PatentEP3098147B1Wheel protector for a bicycle and method for the preparation of a wheel protector
Publication Date: 2022.12.28 SKS METAPLAST SCHEFFER KLUTE GMBH
  • EP3098147B1 patent drawingFigure 1~2

AI summary

Wheel guard for a bicycle, comprising a wheel guard body (1) which is made at least partially and/or sectionally of plastic, and carrier means (2) for decoration and/or information, wherein the wheel guard body (1) and the carrier means (2) are firmly connected to each other by back injection molding.