Composite Fin Plug With Foam-Filled Recesses for Bonding

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Solution Overview

Problem

Existing fin plugs for watercrafts face issues such as a flawed bond with resinous material, deformation under load, and increased strain on connections due to insufficient surface area, leading to reduced performance and potential cracking or shattering of the fiberglass skin.

Innovation Solution

A composite fin plug with a plastics material featuring a top surface with recesses or apertures filled with foam material, which forms a surface for bonding with an overlying glass layer, and includes a honeycomb-like structure with apertures and rib elements to enhance strength and bonding, along with grub screws and biasing means for secure fin retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a traditional fin plug with a single cavity and flange section is used, then the fin can be securely attached to the surfcraft, but the bond between the fin plug and resinous material becomes flawed and the fiberglass skin may crack or shatter under pressure

Engineering Contradiction:
Improvebond strength between fin plug and resinous materialVSAvoidintegrity of fiberglass skin
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The fin plug is divided into multiple cavities (first cavity and second cavity) instead of a single cavity, allowing the fin base to be segmented and attached to multiple separate plugs. This distributes the mechanical stress and pressure across multiple bonding points, preventing concentration of forces that would cause bond failure or fiberglass cracking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fin plug features a rounded head portion with a radius of curvature specifically designed to match the contour of the fin base, creating an optimized local bonding interface. This localized geometric matching enhances the bond quality at the critical contact point between the fin and plug, improving stress distribution and preventing bond failure.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If a large fin plug with elongated cavity and flange section is used, then the fin cavity can be formed, but the installation process becomes slow due to requiring a two-step cavity routing process

Engineering Contradiction:
Improveformation of fin cavityVSAvoidinstallation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The fin plug is segmented into multiple smaller cavities rather than one large elongated cavity. This allows each cavity to be formed independently and more quickly, eliminating the need for a complex two-step routing process while still providing sufficient structural support for fin attachment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of forming a large cavity and then subdividing it (the traditional two-step process), the invention inverts the approach by using multiple smaller cavities from the start. Each small cavity can be routed independently in a single step, dramatically simplifying the manufacturing process and increasing installation productivity.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If the fin plug has a single cavity design, then the structure is simple, but the surface area for bonding with resinous material is insufficient, leading to increased strain on the connection

Engineering Contradiction:
Improvefin plug structureVSAvoidconnection strength between fin plug and resinous material
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The single cavity is segmented into multiple cavities (first and second cavities), which increases the total surface area available for bonding with resinous material. This enhanced bonding surface area distributes the mechanical strain across multiple contact points, significantly improving connection strength while keeping the overall plug structure relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fin plug design extends in multiple dimensions with cavities arranged in different spatial orientations. This multi-dimensional arrangement maximizes the bonding surface area within a compact volume, increasing connection strength without proportionally increasing the overall size or complexity of the plug.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 composite fin plug achieves a stronger bond with the resinous material, reduces deformation, and enhances structural integrity, leading to improved performance and durability by distributing forces effectively and preventing cracking.

Implementation Method 1

the foam material in the top surface is adapted to form, in use, a surface for bonding with an overlying glass layer of a water craft

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

A composite fin plug with a plastics material featuring a top surface with recesses or apertures filled with foam material

Methodology Applied
Scientific EffectMechanical interlocking:

Implementation Method 3

includes a honeycomb-like structure with apertures and rib elements to enhance strength and bonding, along with grub screws and biasing means for secure fin retention

Methodology Applied
Scientific EffectForce distribution:

Implementation Method 4

The composite fin plug achieves a stronger bond with the resinous material, reduces deformation, and enhances structural integrity, leading to improved performance and durability by distributing forces effectively

Methodology Applied
Scientific EffectStructural reinforcement:

Data Source

PatentEP2920053B1A fin plug for a water craft
Publication Date: 2019.04.03 FIN CONTROL SYST
  • EP2920053B1 patent drawingFigure 1A~1B
  • EP2920053B1 patent drawingFigure 2A~2B
  • EP2920053B1 patent drawingFigure 2C~2D

AI summary

A fin plug (10) for a water craft, said fin plug (10) including: a top surface (15) and a bottom surface (20); at least one fin cavity (25), for receiving a base element of a fin, extending inwardly from at least one opening in the top surface (15); and at least one hole (35) or recess in the top surface (15) adapted to be filled with foam.