Annular Adhesive Bead Application for Aircraft Nutplates

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Solution Overview

Problem

Current adhesive material application techniques rely on installer skill, leading to inconsistent and insufficient adhesive application, resulting in failed attachments or contamination, particularly when applying annular beads to nutplates in aircraft skin panels, which can cause nutplates to be inadequately secured or rendered inoperable.

Innovation Solution

An adhesive applicator device with a nozzle featuring an annular flow path and concentric walls that dispenses a precise annular bead of adhesive material around nutplate fastener holes, using a precision sealant dispensing system with pulsed volume control to ensure consistent application and prevent adhesive migration into holes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If installer skill-based application techniques are used, then flexibility and adaptability are maintained, but manufacturing precision and consistency of adhesive application deteriorate

Engineering Contradiction:

Improveinstaller skill flexibilityVSAvoidadhesive application consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent replaces manual installer skill-based application with an automated adhesive applicator device that uses a controlled delivery system, pulsed volume control, and computer-controlled positioning to achieve consistent adhesive application. This substitution eliminates human variability while maintaining the ability to adapt to different applications through programmable control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs pulsed volume control and controlled delivery parameters to precisely regulate adhesive flow rate, bead size, and placement positioning. By dynamically adjusting these parameters, the system achieves consistent manufacturing precision while maintaining adaptability to different nutplate configurations and adhesive types.

Inventive Principle:

Principle #35Parameter changes

2Strength

If adhesive material is applied in sufficient quantity to securely attach nutplates, then attachment strength is improved, but adhesive migration into fastener holes increases causing contamination

Engineering Contradiction:

Improvenutplate attachment strengthVSAvoidadhesive migration and contamination

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent employs a nozzle with an annular outlet that delivers adhesive in a precisely controlled annular bead pattern. The local geometry of the nozzle creates a specific adhesive flow distribution that concentrates adhesive where needed for strong attachment while preventing overflow into the fastener hole, thus achieving both strength and contamination prevention.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a floating element within the nutplate fastener hole that acts as a barrier to prevent adhesive migration into the hole. This intermediary component allows sufficient adhesive to be applied for strong attachment while blocking the harmful effect of adhesive contamination that would otherwise occur.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If adhesive bead surface area is increased to ensure secure attachment, then attachment reliability is improved, but adhesive flow into fastener holes increases causing jamming

Engineering Contradiction:

Improveattachment reliabilityVSAvoidadhesive flow into fastener hole

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the adhesive delivery system into distinct functional zones: an annular outlet port that creates a controlled bead pattern, an annular flow path that directs adhesive away from the fastener hole, and a floating element that segments the fastener hole space to block adhesive entry. This segmentation allows large adhesive surface area for reliability while preventing harmful flow into the hole.

Inventive Principle:

Principle #1Segmentation

4Device complexity

If manual adhesive application is used to maintain operational simplicity, then device complexity is reduced, but manufacturing precision and consistency deteriorate

Engineering Contradiction:

Improveapplication system simplicityVSAvoidadhesive bead consistency

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent designs the nozzle with self-aligning features including a positioning bore that receives a positioning销 to automatically center the nozzle over the nutplate fastener hole. This self-service alignment mechanism eliminates the need for complex external positioning systems while ensuring consistent adhesive application precision.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP2740540B1Annular adhesive bead application

Publication Date: 2017.10.18 LOCKHEED MARTIN CORP

AI summary

Application of uncured adhesive material in bead ring on a surface using a device that includes a nozzle comprising a nozzle intake port, a nozzle outlet port, and a nozzle cavity connecting and providing fluid communication between the inlet and outlet ports. The nozzle intake port receives uncured adhesive material into the nozzle cavity from a source of uncured adhesive material. The outlet port has an annular shape that forms an annular bead of adhesive material on a surface onto which the nozzle is dispensing adhesive material. The nozzle cavity comprises an annular flow path leading to the annular outlet port and shaped to dispense adhesive material through the outlet port axially. The nozzle comprises inner and outer concentric walls defining the annular flow path therebetween.