Robot Wrist Axis Offset for Expanded End-Effector Motion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The movable range of the wrist part and end effector in existing robot devices is limited due to the perpendicular alignment of the second axis relative to the first axis, restricting the operational flexibility and workability.

Innovation Solution

The second axis is positioned parallel to and deviated from the first axis in a perpendicular direction, allowing the second link to rotate in a larger range without interference, with a supply line layout that accommodates this deviation through insertion holes and a gap space, ensuring the supply line curvature remains manageable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the second axis is perpendicular to the first axis, then the robot structure is compact and simple, but the movable range of the wrist part and end effector is limited

Engineering Contradiction:
Improvemovable rangeVSAvoidaxis arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent deviates the second axis from the first axis in a direction perpendicular to both the first axis and the first perpendicular direction, creating a three-dimensional offset configuration. This dimensional change allows the wrist part and end effector to access additional spatial regions, expanding the movable range without simply increasing the perpendicular offset distance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces asymmetric positioning of the second axis relative to the first axis, where the second axis is deviated by a specific distance in a perpendicular direction. This asymmetric arrangement creates unequal clearance zones that enable broader rotational movement of the second link and hand part, transforming the symmetric perpendicular configuration into an asymmetric offset configuration that maximizes operational envelope.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If the second link rotates in a larger range, then the workability is improved, but the supply line curvature increases causing potential damage

Engineering Contradiction:
ImproveworkabilityVSAvoidsupply line curvature stress
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent positions the second axis to be deviated from the first axis in a direction perpendicular to both axes, creating a three-dimensional offset configuration. This spatial arrangement allows the supply line to follow a more gradual curved path through the gap space, reducing bending stress while enabling the second link to rotate through a larger angular range for improved workability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent embeds the supply line within a dedicated line space formed by insertion holes in the first and second links, with the supply line nested in the gap space between them. This nested arrangement protects the supply line from external damage while accommodating rotational movement, as the supply line can flex within the protected gap space without experiencing excessive curvature stress.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3954506B1Robot device
Publication Date: 2025.07.02 KAWASAKI JUKOGYO KK
  • EP3954506B1 patent drawingFigure 1
  • EP3954506B1 patent drawingFigure 2
  • EP3954506B1 patent drawingFigure 3

AI summary

A robot device 1 includes a first link 11 configured to rotate on a first axis L1, a second link 12 supported by a tip-end part of the first link 11 so as to be rotatable on a second axis A2, and a hand part 15 supported by a tip-end part of the second link 12. When one direction perpendicular to the first axis L1 is a first perpendicular direction Y, and a direction perpendicular to both the first axis L1 and the first perpendicular direction Y is a second perpendicular direction Z, the second axis L2 extends in parallel to the first perpendicular direction Y and is deviated from the first axis L1 in the second perpendicular direction Z.