Composite Fastening via Distance Compensation Insert

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Solution Overview

Problem

Existing devices for connecting structural elements made of fiber-reinforced plastic composite materials face issues such as damage from tightening torque, space constraints, and unsightly protruding screw heads, making them unsuitable for applications like aircraft construction where stability and aesthetics are critical.

Innovation Solution

A device that integrates a distance compensation element via a threaded connection to an insert part, which is glued within the structural element, allowing for adhesive bonding and avoiding external load introduction, thus providing a space-saving and aesthetically pleasing solution by converting the rotational movement of the connecting screw into axial extension within the structural element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the screw head is supported on the component to maintain stability, then the connecting strength is improved, but the component may be damaged by tightening torque and the appearance is degraded

Engineering Contradiction:
Improveconnecting strengthVSAvoiddamage to component and appearance degradation
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The screw head is extracted from the component surface and relocated to the distance compensation element. The distance compensation element acts as an intermediary carrier that bears the tightening torque and connecting strength requirements, while the component surface remains undisturbed and undamaged.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The distance compensation element serves as an intermediary between the screw head and the component. It absorbs the mechanical stress and torque during tightening, preventing direct contact and potential damage to the component while maintaining the necessary connecting strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the distance compensation element is connected to the nut of the retaining element, then the tolerance compensation function is achieved, but space problems occur making it unsuitable for composite components

Engineering Contradiction:
Improvetolerance compensation functionVSAvoidspace requirements
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The distance compensation element is merged with the insert part by integrating the threaded connection directly into the insert part structure. This consolidation eliminates the need for separate nuts and retaining elements, significantly reducing the overall space requirements while maintaining the tolerance compensation function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The threaded connection of the distance compensation element is nested within or integrated into the insert part structure. This nesting approach allows the distance compensation mechanism to occupy minimal additional space within the existing component geometry, making it suitable for thin-walled composite components.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If the connecting screw is fixed with the screw head on the upper side of the composite material, then the connection is simplified, but the structural integrity is compromised due to punctiform load introduction

Engineering Contradiction:
Improveconnection simplicityVSAvoidstructural integrity of composite material
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The screw head is extracted from direct contact with the composite material surface. The distance compensation element with its threaded connection serves as an intermediate structure that distributes loads away from the composite material, preventing punctiform stress concentration and preserving structural integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The distance compensation element acts as a mediator between the connecting screw and the composite structural element. It provides a transition that distributes mechanical loads over a larger area, avoiding concentrated stress points that would compromise the composite material's structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design enhances the structural integrity and safety of composite materials while maintaining a clean surface appearance, offering a resilient and stable connection suitable for thin-walled fiber-reinforced plastic components, particularly in aircraft construction.

Implementation Method 1

fixed immovably to the adjacent material of the structural element by means of an adhesive connection

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

Frictional engagement with the connecting screw connectable entraining element, so that the distance compensation element can be converted into a stop position

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3114359B1Device for connecting a structural element with a holding element spaced apart
Publication Date: 2020.02.26 FACC
  • EP3114359B1 patent drawingFigure 1~2
  • EP3114359B1 patent drawingFigure 3~7
  • EP3114359B1 patent drawingFigure 4a~4b

AI summary

Device (4) for spaced apart connection of a structural element (1), in particular made from a fiber-reinforced plastic composite material, with a holding element (5) by means of a connection screw (7), with a distance compensation element (8) having a longitudinal bore (9) for the passage of the connection screw (7), and with an entraining element (16) arranged in the longitudinal bore (9), which can be connected to the connection screw (7) by means of a friction fit, so that the distance compensation element (8) can be transferred into an abutment position bridging the distance between the structural element (1) and the holding element (5) by screwing in of the connection screw (7), wherein the distance compensation element (8) is connected to an insertion part (11) via a screw connection (10), which part comprises a fastening section (12) that can be arranged within the structural element (1) for bonding with the structural element (1).