Fuselage Circumferential Lap Splices Without Splice Straps

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Solution Overview

Problem

Circumferential splicing in aircraft fuselage assembly adds significant weight and labor due to the use of splice straps and numerous affixation components, complicating the alignment process.

Innovation Solution

The use of complementary skins with features like shiplap joins and rabbet joins, eliminating the need for splice straps, enhances strength and reduces complexity by aligning and assembling circumferential splices without additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If circumferential splicing uses splice straps and numerous affixation components, then the structural strength is improved, but the weight increases substantially and the complexity of alignment increases

Engineering Contradiction:
Improvestructural strengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent removes the splice strap component from the circumferential splice assembly, extracting only the necessary affixation components while eliminating the heavy strap structure. This allows the skin itself to provide the structural connection through precisely formed edges and grooves, maintaining strength while reducing weight.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by forming specific geometric features (edges, grooves, recesses) only at the precise locations where structural connection is needed. The skin portions are locally modified with grooves and recesses to receive affixation components, rather than applying a uniform structural solution across the entire splice area.

Inventive Principle:
Principle #3Local quality

2Strength

If circumferential splicing uses splice straps and numerous affixation components, then the structural strength is improved, but the complexity of alignment and assembly increases

Engineering Contradiction:
Improvestructural strengthVSAvoidalignment complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming the skin edges, grooves, and recesses during skin fabrication before the actual splice assembly. The grooves and recesses are created in advance with precise geometry, so that during assembly, components simply need to be inserted into these pre-prepared features rather than requiring complex alignment procedures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The skin structure itself serves as the alignment mechanism through its geometric features. The grooves and recesses formed in the skin automatically guide and position the affixation components during assembly, making the structure self-aligning and eliminating the need for external alignment fixtures or complex positioning procedures.

Inventive Principle:
Principle #25Self-service

3Strength

If circumferential splicing uses splice straps and numerous affixation components, then the structural strength is improved, but the labor required for installation increases

Engineering Contradiction:
Improvestructural strengthVSAvoidlabor efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

By removing the splice strap and reducing the number of affixation components to only those absolutely necessary for structural connection, the patent significantly reduces the number of installation steps and labor hours required. The simplified assembly process focuses on inserting and securing minimal components into pre-formed skin features.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pre-forming of grooves, recesses, and edge features during skin fabrication transfers labor from the assembly stage to the manufacturing stage, where automated processes can be more efficiently applied. This preliminary preparation dramatically reduces the manual labor and time required during actual splice installation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4015360B1Circumferential lap splices for sections of fuselage
Publication Date: 2025.08.27 THE BOEING CO
  • EP4015360B1 patent drawingFigure 1
  • EP4015360B1 patent drawingFigure 2
  • EP4015360B1 patent drawingFigure 3

AI summary

Systems and methods are provided for splicing airframe components. One embodiment is a method for assembling an airframe of an aircraft. The method includes forming a first skin of a first circumferential section of fuselage, the first skin including a distal portion comprising a lip and a shoulder, aligning a second skin of a second circumferential section of fuselage with the shoulder such that the lip overlaps the second skin, and affixing the first skin and the second skin together via a circumferential splice.