Passive Tool Coupling Lock for Power-Free End Effector Change

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Solution Overview

Problem

Conventional pipe handling operations, such as drill pipe handling, are labor-intensive and dangerous, and robotic systems lack versatility and efficient power-assisted end effector interchangeability.

Innovation Solution

A passive coupling mechanism that allows tools to be interchanged by rotating one portion relative to another, eliminating the need for hydraulic, pressurized air, or electrical power to engage or disengage, and featuring a housing with an engaging lock that secures the connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hydraulic, pressurized air, or electrical power systems are used to assist end effector engagement and disengagement, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of operationVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The coupling mechanism uses the rotational motion of the tool arm itself to drive the locking mechanisms through mechanical engagement. The engaging lock rotates with the tool arm and automatically drives the locking balls or cams into the locked position, eliminating the need for external power systems while maintaining ease of operation through simple rotational motion.

Inventive Principle:
Principle #25Self-service

2Power

If a robot is equipped with power systems for moving the robot, then the power is improved, but the power for coupling and decoupling tools may not be present or desirable

Engineering Contradiction:
ImprovepowerVSAvoidadaptability or versatility
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The coupling mechanism is divided into separate functional components: the engaging lock that rotates with the tool arm, the locking mechanisms that engage with the fixture, and the tool portion that remains stationary during coupling. This segmentation allows the robot's existing power system to drive only the necessary rotating components while leaving other components passive, maintaining versatility across different robotic applications.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If end effectors are interchanged manually, then the adaptability is improved, but the productivity decreases due to labor-intensive operations

Engineering Contradiction:
Improveadaptability or versatilityVSAvoidproductivity
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The fixture is pre-configured with alignment features and locking mechanisms that automatically engage when the tool arm rotates into position. The engaging lock is pre-positioned to drive the locking mechanisms as soon as rotation begins, eliminating the need for manual intervention during the coupling process and enabling rapid end effector interchange.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4146422B1Passive rotation disconnect
Publication Date: 2026.03.25 NAT OILWELL VARCO LP
  • EP4146422B1 patent drawingFigure 1
  • EP4146422B1 patent drawingFigure 2
  • EP4146422B1 patent drawingFigure 3~4

AI summary

A coupling mechanism for securing a tool to a tool arm may include a housing and an engaging lock. The engaging lock may be arranged within the housing and configured for rotation by the tool arm. Rotation of the engaging lock may drive locking mechanisms partially through the housing to establish a longitudinally secured connection.