Multi-Junction Coupling Structure for Tool-Free Shape Variation

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Solution Overview

Problem

Existing extendable arms and visual interest stimulating structures require time-consuming configurations for coupling multiple rigid members, as they are typically overlapped at a single junction point, making assembly cumbersome.

Innovation Solution

A coupling structure that allows easy assembly by rotatably coupling two rigid members with a plurality of junction points using horizontal coupling parts with convex and concave parts, enabling multiple rigid members to be connected without tools, and allowing for flexible and complex shape variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple rigid members are coupled at a single junction point by forming through holes and inserting a central coupling shaft, then the structure can be assembled, but the assembly process becomes time-consuming and cumbersome

Engineering Contradiction:
ImproveAssembly easeVSAvoidAssembly time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The coupling structure is divided into multiple coupling portions (first, second, third coupling portions) distributed at different junction points along the rigid members. Instead of using a single central coupling shaft at one junction point, the invention segments the coupling function across multiple locations, allowing parallel assembly operations and reducing overall assembly time while maintaining structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces coupling portions with convex and concave fitting parts as intermediary elements between rigid members. These coupling portions act as mediators that simplify the joining process by providing pre-formed coupling interfaces, eliminating the need to form through holes and insert shafts at each junction point, thereby reducing assembly time and complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If multiple rigid members are coupled at a single junction point, then the structure can be assembled, but the configuration becomes complex and time-consuming

Engineering Contradiction:
ImproveCoupling configuration complexityVSAvoidAssembly ease
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The coupling system is segmented into multiple independent coupling portions located at different positions along the rigid members. Each coupling portion functions independently with its own convex-concave fitting mechanism, simplifying the overall configuration by distributing complexity across multiple simple, standardized units rather than concentrating complexity at a single junction point

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of forming through holes in rigid members and inserting coupling shafts (traditional approach), the invention inverts the approach by providing convex fitting parts on coupling portions that fit into concave parts, eliminating the need for through holes and complex shaft insertion procedures, thereby simplifying the coupling configuration and easing assembly

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4249190B1Coupling structure including plurality of coupling portions and shape varying member
Publication Date: 2026.02.18 FUJIMIYASEISAKUSHO
  • EP4249190B1 patent drawingFigure 1
  • EP4249190B1 patent drawingFigure 2
  • EP4249190B1 patent drawingFigure 3

AI summary

The invention relates to a shape-variable multiple junction point extendable structure that is configured to extend and contract by coupling a plurality of coupling structures 20. Each of the coupling structures 20 includes two rigid members 21, and a plurality of horizontal coupling parts 40 each attached to a respective one of the rigid members 21. Each of the horizontal coupling parts 40 is capable of being rotatably coupled to each other. In each of the coupling structures 20, the horizontal coupling parts 40 attached to a central part of each of the rigid members 21 are coupled to each other. In each of the coupling structures 20, each of the horizontal coupling parts 40 attached to an end part of each of the rigid members 21 is coupled to the horizontal coupling part 40 of another coupling structure 20.