Cutting Fastener Assembly for Precise Hole Alignment

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Solution Overview

Problem

Current assembly methods for elementary parts, such as those in aircraft structures, are inefficient due to the need for precise alignment, complex tooling, and potential pollution from drilling residues, with existing processes being lengthy or difficult to implement, especially in complex environments.

Innovation Solution

A fastening system comprising an elongated element with a cutting member that allows for separate drilling of parts in a workshop, enabling precise positioning and assembly by enlarging holes using the cutting member, which reduces the need for bulky tools and minimizes residue risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If separate drilling of parts is performed in a workshop, then manufacturing precision is improved, but assembly time and complexity increase

Engineering Contradiction:
Improvepositioning precisionVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

Holes are drilled separately in the workshop before assembly, allowing precise positioning and cleaning to be performed in advance. This preliminary action ensures high manufacturing precision while the pre-assembled state with alignment features reduces on-site assembly time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The drilling operation is segmented from the assembly operation, allowing each to be optimized independently. Drilling is performed separately in a controlled workshop environment for precision, while assembly uses pre-drilled components with alignment features to reduce on-site time.

Inventive Principle:
Principle #1Segmentation

2Productivity

If permanent holes are drilled simultaneously in component parts, then assembly speed is improved, but device complexity and tooling requirements increase

Engineering Contradiction:
Improveassembly speedVSAvoidtooling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Holes are drilled in advance in the workshop before assembly, eliminating the need for complex simultaneous drilling tooling during assembly. This preliminary action simplifies on-site tooling while maintaining assembly speed through pre-prepared components.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If high clamping force is applied during drilling, then manufacturing precision is improved, but ease of operation deteriorates in complex environments

Engineering Contradiction:
Improvehole alignment precisionVSAvoidtool arrangement ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

Components are clamped and drilled together in the workshop under controlled conditions where heavy clamping can be applied easily. This preliminary action achieves high precision while avoiding the need to arrange heavy clamping tools in difficult on-site environments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Alignment features such as protrusions and recesses act as intermediaries to maintain precise hole alignment without requiring heavy clamping during assembly. These features automatically position components correctly, eliminating the need for complex clamping arrangements in the field.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If match drilling is performed with simultaneous drilling of temporary and final holes, then manufacturing precision is improved, but loss of time increases due to multiple cleaning steps

Engineering Contradiction:
Improvehole alignment precisionVSAvoidcleaning time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

Temporary holes are drilled and cleaned in the workshop before assembly, performing the cleaning action in advance when it is more efficient. This eliminates the need for on-site cleaning operations and reduces overall assembly time while maintaining precision through controlled workshop conditions.

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 method simplifies the assembly process by allowing separate drilling and positioning of parts, reducing the complexity of tooling requirements and minimizing residue pollution, while enabling precise alignment and efficient assembly of complex shapes.

Implementation Method 1

a cutting member configured to cut at least one second component by exerting a first cutting action on the at least one second component, thereby enlarging the second hole to a first hole diameter that corresponds to a diameter of the initial section

Methodology Applied
Scientific EffectCutting: Abrasion

Implementation Method 2

wherein the fastener comprises a ferrule configured to be deformed by compression to be crimped onto the initial section

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

or a nut configured to be screwed onto the initial section

Methodology Applied
Scientific EffectScrewing: Screw

Implementation Method 4

A tool is then positioned to pull on the tension segment. Simultaneously, an anvil in the tool pushes, deforms, and rivets the ferrule into locking grooves in the initial segment to secure the ferrule to the initial segment. The diameter of the ferrule is reduced, and its height increases. The initial segment elongates until the fusible segment breaks.

Methodology Applied
Scientific EffectTension: Tension

Data Source

PatentEP4174330B1Method and attachment for assembling at least two basic parts
Publication Date: 2025.01.22 EUROCOPTER FRANCE SA
  • EP4174330B1 patent drawingFigure 1~4
  • EP4174330B1 patent drawingFigure 5~8
  • EP4174330B1 patent drawingFigure 9~11

AI summary

The present invention relates to a method and a fastener (1) configured for assembling at least two elementary parts by clamping them, said fastener (1) comprising a first component (2), the first component being provided with a head (5) extended by an elongated element (10), said elongated element (10) comprising along a geometric axis (AX) an initial section (11) and an end section (12), the initial section (11) extending along said geometric axis (AX) from the head (5), the end section (12) forming a free end (15) of the elongated element (10). The initial section (11) is contained within a first geometric cylinder (111) of a first geometric diameter (D111) greater than a second geometric diameter (D112) of a second geometric cylinder (112) containing the end section (12), said elongated element (10) comprising a cutting member (200).