Rivet Head Sealant Nozzle for Uniform Viscous Application

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Solution Overview

Problem

Existing methods for applying polymerizable sealants to rivet heads in the aeronautical field are inefficient and difficult to automate due to the need for precise control of bead section and uniformity, with prior devices being poorly suited to viscous sealants and prone to issues like shear and needle distortion, leading to reproducibility and reliability problems.

Innovation Solution

A device comprising a cylindrical cartridge with a dispensing end and pressure end, a buttoning nozzle with a pre-filling chamber and bell-shaped cavity, and a movable needle for controlling the sealant flow, allowing for precise and reproducible application of sealant to rivet heads through automated sequencing of pressure and needle movement, avoiding thread formation and allowing for easy cartridge replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a needle is used to control sealant flow in viscous products, then the flow can be interrupted or allowed, but the needle disrupts the flow causing shear and gaps in deposited material

Engineering Contradiction:
Improveflow controlVSAvoiddeposited material uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The needle is extracted from the sealant flow path. Instead of having the needle pass through or contact the sealant, the system uses a valve mechanism located upstream that controls flow without disrupting the sealant in the dispensing path, eliminating shear and gaps in the deposited material

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A valve mechanism acts as an intermediary between the pressure source and the dispensing nozzle. This intermediary controls the sealant flow through pressure regulation without the controlling element needing to contact the sealant, thus maintaining flow uniformity while enabling precise control

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If manual smoothing with a spatula is used to achieve desired bead section, then uniformity can be obtained, but the operation becomes long and costly

Engineering Contradiction:
Improvebead section uniformityVSAvoidoperation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The dispensing system is designed to automatically produce the desired bead section without requiring manual intervention. The combination of pressure control, needle positioning, and nozzle design enables the system to self-regulate the sealant flow to achieve uniform deposition, eliminating the need for spatula smoothing

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical smoothing operation with a spatula is replaced by a controlled dispensing mechanism that achieves uniformity through precise flow control and positioning, substituting automated mechanical control for manual mechanical manipulation

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

3Manufacturing precision

If operator dexterity is used to adjust nozzle speed and flow rate, then bead uniformity can be guaranteed, but automation becomes difficult

Engineering Contradiction:
Improvebead uniformityVSAvoidapplication automation
Core Design Contradiction:
Manufacturing precisionVSExtent of automation

Solution Approach 1:

The system incorporates feedback mechanisms through automated control of needle positioning and pressure regulation. Sensors and control systems monitor the dispensing process and automatically adjust parameters to maintain bead uniformity, replacing operator dexterity with automated closed-loop control

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses dynamic control mechanisms where the needle position and pressure are continuously adjusted during the dispensing process. This dynamic adaptation allows the automated system to respond to varying conditions and maintain uniform bead deposition without manual intervention

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If complex pressure and flow rate control means are used, then application precision can be improved, but device complexity increases

Engineering Contradiction:
Improveapplication precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system applies control locally at critical points in the dispensing path. Rather than complex overall system control, the needle position and local pressure regulation at the dispensing point provide precise control with minimal complexity. The control is focused where it is most needed - at the sealant flow path

Inventive Principle:
Principle #3Local quality

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 solution enables precise and reproducible application of sealant to rivet heads, preventing soiling outside planned areas and ensuring consistent coverage, facilitating automation and efficient operation even during polymerization, with the ability to handle different sealant types and viscosities.

Implementation Method 1

pressure means acting on the pressure end of the cartridge to cause the ejection of the activated sealant from the dispensing end

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Implementation Method 2

a closing needle, movable in translation between a closed position where the end of the needle obstructs the application orifice of the nozzle and an open position where the end of the needle is away from the application orifice

Methodology Applied
Scientific EffectPhysical obstruction control: Valve

Implementation Method 3

an application assembly comprising a sealant supply conduit into a buttoning nozzle which includes a pre-filling chamber, a bell-shaped cavity adapted to cap the rivet head, an application orifice connecting the pre-filling chamber and the bell-shaped cavity

Methodology Applied
Scientific EffectViscous flow:

Data Source

PatentEP3797875B1Method for automatically applying a viscous product to a rivet head
Publication Date: 2022.05.04 DAHER AEROSPACE
  • EP3797875B1 patent drawingFigure 1
  • EP3797875B1 patent drawingFigure 2
  • EP3797875B1 patent drawingFigure 3

AI summary

The invention relates to a method for applying a polymerizable sealant, implementing a device comprising: - a substantially cylindrical cartridge (210) comprising an activated polymerizable sealant, said cartridge having a dispensing end (211) and a pressure end (212); - a receptacle (110) for said cartridge comprising a connection interface (111) with its dispensing end; - pressure means (215) acting on the pressure end (212) of the cartridge to cause the ejection of the activated sealant from the dispensing end (211); - an application assembly (120) comprising a nozzle having an application orifice and a sealant supply conduit (122) into said nozzle;- said device comprising a closing needle (130), movable in translation between a closed position where the end of the needle obstructs the application orifice of the nozzle and an open position where the end of the needle is away from the application orifice, means (135) for maneuvering the needle in translation between these two positions.;