Articulated Laparoscopic Joint Cable Routing

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Solution Overview

Problem

Robotic surgical instruments face challenges in providing sufficient articulation, torque transmission, and mechanical manipulation while maintaining deterministic end effector position and resisting external loading, which is not effectively addressed by existing technologies.

Innovation Solution

The design incorporates a wrist assembly with a first and second joint, featuring arcuate surfaces and apertures for the electrical cables, allowing them to roll and articulate without longitudinal translation, coupled with knuckle gearing to maintain rolling contact and prevent non-deterministic end effector location, enabling high articulation (+/−70 degrees) with minimal bend radius and reduced stress on cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cables are routed through articulated joints to enable wrist movement, then articulation capability is improved, but cable wear and abrasion increase due to repeated bending and contact

Engineering Contradiction:

Improvearticulation capabilityVSAvoidcable lifespan

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs arcuate surfaces with specific radii of curvature (e.g., 0.5 inch to 2 inch radius) that match the cable bend radius. These curved surfaces guide the cables through the articulation range without sharp bends, reducing stress and wear while maintaining full wrist articulation capability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces arcuate guide surfaces as intermediary elements between the articulating joint components and the electrical cables. These surfaces act as mediators that distribute cable contact forces and prevent direct rubbing against sharp edges or high-stress contact points.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If electrical cables are positioned close to arcuate surfaces for compact design, then device size is reduced, but cable stress and potential damage from contact increase

Engineering Contradiction:

Improvedevice sizeVSAvoidcable stress and contact damage

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies different surface properties to different regions of the joint components. The arcuate surfaces have specifically engineered radii of curvature that are larger than the cable bend radius, creating a local quality that protects cables in high-stress zones while maintaining compact overall device dimensions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The arcuate surfaces are pre-configured with radii of curvature that anticipate and prevent cable damage before it occurs. By designing surfaces with sufficient radius (0.5-2 inches) before assembly, the system preemptively eliminates sharp contact points that would cause cable stress during articulation.

Inventive Principle:

Principle #9Preliminary anti-action

3Adaptability or versatility

If multiple cables are routed through articulated joints for full functionality, then end effector capability is improved, but deterministic positioning becomes difficult due to cable interference and non-linear movement

Engineering Contradiction:

Improveend effector capabilityVSAvoidend effector positioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the cable routing paths by providing dedicated arcuate surfaces for different cables at different locations on the joint components. This segmentation isolates each cable's movement path, preventing interference between cables and ensuring that each cable's movement corresponds predictably to joint articulation angles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent designs the arcuate surfaces to dynamically adapt to the articulation angle, with surfaces that guide cables through optimal paths at each joint position. This dynamic routing maintains consistent cable tension and prevents cross-cable interference across the full range of motion, preserving positioning accuracy.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12156709B2Highly articulated laparoscopic joint including electrical signal transmission therethrough

Publication Date: 2024.12.03 COVIDIEN LP

AI summary

A robotic electromechanical surgical instrument includes a housing, an elongated shaft that extends distally from the housing, a wrist assembly supported on the elongated shaft, an end effector coupled to the wrist assembly, cables coupled to the wrist assembly, and an electrical cable coupled to the end effector. The wrist assembly includes a first joint coupled to a second joint. The first joint includes a proximal segment defining an arcuate surface and a distal segment defining an arcuate surface. The electrical cable is positioned relative to the proximal arcuate surface and the distal arcuate surface such that during articulation of the wrist assembly the electrical cable rolls off of the distal arcuate surface as the electrical cable rolls on to the proximal arcuate surface and the electrical cable rolls off of the proximal arcuate surface as the electrical cable rolls on to the distal arcuate surface.