Intermediate Link Rotation Lock for Stable Tool Arm Positioning

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Solution Overview

Problem

Tool arm assemblies often experience unintentional rotation of arm links when users remove their hands, leading to safety issues and unintended tool movement.

Innovation Solution

An intermediate link with a second rotation lock mechanism that allows users to selectively prevent rotation of arm links, featuring a pin with a locked and unlocked position to engage with a lock interface area, ensuring the tool remains stationary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If intermediate links allow arm links to rotate freely about the rotation axis for tool positioning flexibility, then the ease of operation and positioning precision are improved, but unintentional rotation occurs when users remove their hands, leading to safety issues and unintended tool movement

Engineering Contradiction:
Improvetool positioning flexibilityVSAvoidsafety control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The lock mechanism transitions between locked and unlocked states based on user input. When unlocked, the arm link rotates freely for positioning; when locked, rotation is prevented for safety. This dynamic state change resolves the contradiction between operational flexibility and safety control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lock mechanism acts as an intermediary between the arm link and the user's intent. It mediates between the desire for free rotation (positioning flexibility) and the need to prevent unintentional rotation (safety), allowing the system to switch between these opposing requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a lock mechanism is added to prevent unintentional rotation of arm links, then safety and reliability are improved, but the device complexity increases

Engineering Contradiction:
Improvesafety controlVSAvoidlock mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lock mechanism is designed to be self-actuating through a spring-loaded pin that automatically engages with the shaft. The spring provides the locking force, and the mechanism locks itself when the shaft reaches certain positions, reducing the need for complex external locking systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking function is extracted as a separate, modular mechanism (the pin and spring assembly) that can be independently designed and maintained. This separation allows the lock to be a simple add-on component rather than integrating complexity into the entire arm link system.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3344421B1Locking intermediate link for a tool arm assembly
Publication Date: 2021.08.18 LOCKHEED MARTIN CORP
  • EP3344421B1 patent drawingFigure 1
  • EP3344421B1 patent drawingFigure 2
  • EP3344421B1 patent drawingFigure 3

AI summary

An intermediate link for a tool arm assembly is provided. The intermediate link includes first and second connectors that are at least partially rotatable about respective first and second rotation axes. The intermediate link includes first and/or second lock rotation mechanisms that are configured to selectively prevent rotation of the first and second connectors.