Airfoil Cover Panel Locking With Rib Node Cavities and Plugs

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The challenge in manufacturing airfoils, such as fan blades, is to achieve strong bonding and structural strength while minimizing weight, as thick interfacial ribs are often required to secure multiple pieces together, which contradicts the goal of reducing weight.

Innovation Solution

The airfoil design incorporates rib nodes with node cavities and a cover panel featuring tabs that are pinched by plugs, providing a secure and lightweight attachment mechanism, potentially using fiber-reinforced polymer composites and push fasteners with flexible barbs and undercuts for enhanced locking and structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick interfacial ribs are used to bond multiple airfoil pieces together, then structural strength is improved, but weight increases

Engineering Contradiction:

Improvestructural strengthVSAvoidairfoil weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The airfoil is divided into multiple discrete components (body, cover panel, ribs, nodes) that are joined through cavities and locking mechanisms rather than requiring large continuous bonding surfaces. This segmentation allows for strength through precise localized connections rather than extensive material use.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover panel is inserted into the body structure with ribs nested within cavities. The tabs extend into node cavities and are locked by plugs, creating a nested arrangement where components fit within each other to achieve secure bonding without thick interfacial ribs.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If adhesive bonding is used to join airfoil pieces, then manufacturing complexity is reduced, but bonding surface area must be large which increases weight

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidairfoil weight

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent replaces adhesive bonding with a mechanical locking system consisting of tabs, node cavities, and plugs. This mechanical system provides secure joining without requiring large bonding surface areas, thereby reducing weight while maintaining ease of manufacture through straightforward assembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Weight of moving object

If multiple airfoil pieces are used to reduce weight, then overall weight is reduced, but bonding surface area requirements increase

Engineering Contradiction:

Improveairfoil weightVSAvoidbonding surface area

Core Design Contradiction:

Weight of moving objectVSArea of stationary object

Solution Approach 1:

The patent transitions from two-dimensional surface bonding to three-dimensional cavity-based locking. Tabs extend into node cavities and are secured by plugs, utilizing the third dimension (depth) to achieve secure bonding without requiring increased surface area. This dimensional shift allows multiple airfoil pieces to be joined with minimal surface area while maintaining weight reduction benefits.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11203936B2Airfoil with body and cover panel

Publication Date: 2021.12.21 RTX CORP

AI summary

An airfoil includes a body that has rib nodes that each define a node cavity therein. A cover panel is carried on the body over the rib nodes. The cover panel includes tabs that project into the node cavities. Plugs are disposed in the node cavities and pinch the tabs against the node cavities to lock the cover panel on the body.