Joint Function Unit Tensioning to Prevent Displacement

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Solution Overview

Problem

Unintended displacement of a movable-side member occurs due to external forces in conventional joint function units.

Innovation Solution

A joint function unit is designed with a movable-side member supported between a bending and extension position, incorporating a plurality of cord-like members and an elastic body that applies tension to these members to enhance bending rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bendable member is used to join the end effector to the pipe, then the end effector can be displaced along the axis, but unintended displacement occurs when external force is applied

Engineering Contradiction:
Improvedisplacement of end effectorVSAvoidposition stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the physical state of the cord-like member from a loose configuration to a tensioned configuration by introducing an elastic body. This parameter change (from zero tension to positive tension) eliminates looseness and prevents unintended displacement while maintaining the ability to control bending and extension movements.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the cord-like member is made loose to allow bending movement, then the joint can flex, but looseness causes unintended displacement under external force

Engineering Contradiction:
Improvebending capabilityVSAvoidposition stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies tension to the cord-like member through an elastic body, changing its physical state from loose to taut. This parameter change maintains the bending capability by allowing controlled movement while eliminating the harmful looseness that causes unintended displacement under external forces.

Inventive Principle:
Principle #35Parameter changes

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

The elastic body eliminates looseness in the cord-like members, improving bending rigidity and preventing unintended displacement of the movable-side member even under external forces.

Implementation Method 1

an elastic body, supporting the supported part of the plurality of cord-like members on the fixed-side member, energizing the supported part toward a side opposite to the fixed part in the axial direction, and applying tension to the cord-like member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4183534B1Joint function unit
Publication Date: 2025.06.25 NHK SPRING CO LTD
  • EP4183534B1 patent drawingFigure 1
  • EP4183534B1 patent drawingFigure 2
  • EP4183534B1 patent drawingFigure 3

AI summary

Provided is a joint function unit which can suppress an unintended displacement of a movable-side member. This joint function unit 1, in which a movable part 13 is supported by a base part 11 so as to be displaceable in an axial direction thereof, comprises: a plurality of drive wires 19 each having one axial side which is a fixed part 27 fixed to the movable part 13 and the other axial side which is a supported part 29 supported by the base part 11; and an elastic body 21 which supports the supported part 29 of each of the plurality of drive wires 19 on the base part 11, biases the supported part 29 against the fixed part 27 in the axial direction, and applies tension to the drive wires 19.