Composite Extension Boom Fiber Layout for High Deployment Force

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Solution Overview

Problem

Existing extensible booms face challenges in achieving a high extending force without increasing weight, and maintaining stability in the retracted state, particularly when using fiber orientation in laminated unidirectional materials.

Innovation Solution

The extensible boom is made of a fiber-reinforced composite material with controlled fiber orientations, where fibers in different areas form specific angles relative to the extending direction, including low-angle and high-angle directions in distinct sections to enhance extending force and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum alloy is used for the extension boom, then weight is reduced, but surface treatment quality deteriorates due to oxidation and poor adhesion

Engineering Contradiction:
ImproveweightVSAvoidsurface treatment quality
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies composite materials by combining aluminum alloy with a multi-layer coating system consisting of epoxy primer, intermediate coat, and clear coat. This composite structure allows the aluminum alloy to provide lightweight structural support while the coating layers provide corrosion resistance, adhesion, and aesthetic finish, thereby resolving the contradiction between weight reduction and surface treatment quality.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the surface parameters of aluminum alloy through chemical conversion coating (chromate or phosphate treatment) and controlled oxidation processes. These parameter changes modify the surface chemistry and morphology to improve adhesion properties and corrosion resistance, enabling high-quality surface treatment while maintaining the inherent lightweight advantage of aluminum alloy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional multi-step coating process is used, then surface protection is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesurface protectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple coating functions into a integrated multi-layer system where the epoxy primer provides both adhesion and corrosion protection, the intermediate coat provides build and additional protection, and the clear coat provides UV resistance and aesthetics. This merged approach achieves comprehensive surface protection while streamlining the manufacturing process through standardized application procedures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies preliminary surface preparation actions including chemical conversion coating, sanding, and priming before the main coating application. These preliminary actions ensure optimal adhesion and protection while establishing a standardized workflow that reduces variability and simplifies subsequent coating steps, thereby improving surface protection without proportionally increasing manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If extension boom is made modular with joints, then adaptability is improved, but structural integrity deteriorates at connection points

Engineering Contradiction:
ImproveadaptabilityVSAvoidstructural integrity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent segments the extension boom into modular sections connected by telescopic joints, allowing the structure to adapt to different length requirements and configuration needs. This segmentation provides adaptability while the joints are designed with overlapping tubes and mechanical locking mechanisms that maintain structural integrity through distributed load paths and reinforcement at connection points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs nested doll principle through telescopic joint design where inner tubes are inserted into outer tubes with progressive overlapping sections. This nesting arrangement provides adaptability through variable extension lengths while maintaining structural integrity through the nested configuration that distributes mechanical loads across multiple contact surfaces and locking points, preventing stress concentration at single connection points.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4491522B1Extension boom, solar paddle, and method for manufacturing extension boom
Publication Date: 2026.05.06 MITSUBISHI ELECTRIC CORP
  • EP4491522B1 patent drawingFigure 1
  • EP4491522B1 patent drawingFigure 2
  • EP4491522B1 patent drawingFigure 3

AI summary

An extensible boom (120) is made of a fiber-reinforced composite material. When the extended extensible boom (120) is deployed, in a first area, directions of fiber are a first low-angle direction forming a negative angle to a clockwise direction with respect to an extending direction (A) and a second low-angle direction forming a positive angle to the clockwise direction with respect to the extending direction (A). In a second area, directions of fiber are a first high-angle direction forming a negative angle to a clockwise direction with respect to the extending direction (A) and a second high-angle direction forming a positive angle to the clockwise direction with respect to the extending direction (A). The first low-angle direction is closer to the extending direction (A) than the first high-angle direction, and the second low-angle direction is closer to the extending direction (A) than the second high-angle direction.