Self-Locking Panel Joints Without Fasteners or Adhesives

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Solution Overview

Problem

The existing mortise and tenon joint assemblies in aircraft composite structures require additional fixtures, fasteners, and adhesive materials for proper assembly, increasing production costs, labor, and weight, which in turn raises transportation and fuel costs.

Innovation Solution

A self-locking joint system is developed, featuring mortise openings with self-locking end portions and tenon extensions with flexible self-locking members that interlock to form a secure joint without the need for additional fixtures or fasteners, using a method that includes fabricating these elements in composite sandwich panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional mortise and tenon joint assemblies are used, then the joint provides structural connection, but additional fixtures, fasteners, and adhesive materials are required increasing production costs and weight

Engineering Contradiction:

Improvejoint strengthVSAvoidassembly complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent merges the joint connection function with the panel structure itself by integrating mortise openings and tenon extensions directly into the panel components. This eliminates the need for separate fixtures, fasteners, and adhesive materials, reducing assembly complexity while maintaining joint strength through the self-locking interlocking mechanism between the tenon extension and mortise opening.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The joint assembly performs its own alignment and securing functions through the self-locking mechanism where the tenon extension automatically engages with the mortise opening. The flexible self-locking members provide automatic retention without requiring external fasteners or fixtures, allowing the structure to secure itself during assembly.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional fixtures and fasteners are used for assembly, then proper alignment and secure connection are achieved, but labor time and production costs increase

Engineering Contradiction:

Improveassembly reliabilityVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The mortise openings and tenon extensions are pre-formed as integral parts of the panel structures during manufacturing. This preliminary action ensures proper geometry and fit are built-in, eliminating the need for time-consuming alignment adjustments and securing operations with additional fixtures during assembly, while maintaining assembly reliability through the precision of the pre-formed interlocking features.

Inventive Principle:

Principle #10Preliminary action

3Strength

If traditional joint assemblies with fasteners and fixtures are used, then secure connection is achieved, but overall weight of the structure increases

Engineering Contradiction:

Improveconnection strengthVSAvoidstructure weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent extracts and eliminates the separate fasteners, fixtures, and adhesive materials from the joint assembly system. The connection strength is achieved solely through the integrated mortise and tenon interlocking mechanism that is part of the panel structure itself, removing the extra weight of auxiliary connection components while maintaining secure structural connection.

Inventive Principle:

Principle #2Taking out (Extraction)

4Device complexity

If self-locking mechanism is implemented, then additional materials and tools are eliminated, but manufacturing precision requirements increase

Engineering Contradiction:

Improveassembly complexityVSAvoidjoint fabrication precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The precise geometry of the mortise openings and tenon extensions is established during the initial panel manufacturing process rather than during assembly. This preliminary action allows for controlled fabrication precision to be achieved during manufacturing when conditions are more favorable, rather than requiring high precision during field assembly, thereby reducing assembly complexity while maintaining manufacturing feasibility.

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 solution reduces production costs by eliminating the need for additional assembly materials and tools, decreases the weight of aircraft structures, and lowers transportation and fuel costs by providing a lightweight, secure interlocking mechanism.

Implementation Method 1

fabricating on a second portion of the panel structure at least one tenon extension having flexible self-locking members

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8961059B2Self-locking joints for panel structures and methods of fabricating the same

Publication Date: 2015.02.24 THE BOEING CO

AI summary

A method of fabricating a self-locking joint in a panel structure. The method provides a panel structure having at least two face sheets and a core portion sandwiched therebetween. The method further fabricates in a first portion of the panel structure at least one mortice opening having self-locking end portions. The method further fabricates on a second portion of the panel structure at least one tenon extension having flexible self-locking members. The method further interlocks the flexible self-locking members of the at least one tenon extension with the self-locking end portions of the at least one mortice opening to form a self-locking joint in the panel structure.