Foldable PCB Assembly for Compact Surgical Instrument Drives

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Solution Overview

Problem

Robotic surgical systems lack a compact and efficient design for their instrument drive units, which complicates manufacturing, assembly, and heat dissipation, while requiring robustness and durability.

Innovation Solution

An integrated circuit configuration with multiple circuit boards and a nexus, allowing for a transition between open and three-dimensional configurations to accommodate a motor assembly, enhancing manufacturing ease and heat dissipation through ventilation holes, and providing mechanical and electrical engagement with motor components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex instrument drive unit design is used to provide robust and durable assembly, then reliability is improved, but device complexity increases and manufacturing difficulty increases

Engineering Contradiction:
Improverobustness and durabilityVSAvoidcomplex design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The instrument drive unit is divided into modular components including a motor pack, circuit board assembly, and housing. The circuit board assembly itself is segmented into multiple layers with distinct functional zones. This segmentation allows each module to be manufactured and tested independently, then assembled together, maintaining reliability while reducing overall design complexity and facilitating manufacturing.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If more internal components are integrated into the instrument drive unit, then functionality is improved, but space requirements increase and manufacturing difficulty increases

Engineering Contradiction:
ImprovefunctionalityVSAvoidspace requirements
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The circuit board assembly is nested within the motor pack housing, with the circuit board positioned inside the motor assembly cavity. The motor assembly itself is nested within the instrument drive unit housing. This nested arrangement allows multiple functional components to be integrated in a compact configuration, maximizing functionality while minimizing overall volume and simplifying manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If internal components are compacted to save space, then volume is reduced, but heat dissipation becomes more difficult

Engineering Contradiction:
Improvespace savingVSAvoidheat dissipation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The housing and circuit board are designed with localized thermal management features including heat sinks positioned near high-power motor components, ventilation channels in the housing walls, and thermally conductive pathways in the circuit board layout. This local quality approach allows effective heat dissipation in specific hot spots while maintaining compact overall volume, as thermal management is applied only where needed rather than throughout the entire assembly.

Inventive Principle:
Principle #3Local quality

4Temperature

If ventilation holes are added to circuit boards for heat dissipation, then temperature control is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The circuit board incorporates ventilation holes and porous structures that are integrated into the board fabrication process itself. These openings are created during standard PCB manufacturing using drilling and plugging techniques, allowing thermal ventilation without requiring complex post-processing or assembly steps. The porous design provides effective heat dissipation while maintaining compatibility with conventional manufacturing methods.

Inventive Principle:
Principle #31Porous materials

Data Source

PatentEP3463159B1Instrument drive units
Publication Date: 2024.01.03 COVIDIEN LP
  • EP3463159B1 patent drawingFigure 1
  • EP3463159B1 patent drawingFigure 2
  • EP3463159B1 patent drawingFigure 3

AI summary

An integrated circuit includes a nexus and a first, a second, a third, and a fourth circuit board. Each of the first and second circuit boards is coupled to opposing sides of the nexus, and each of the third and fourth circuit boards is coupled to opposing sides of the second circuit board. The integrated circuit is transitionable between a first, open configuration, in which the first, second, third and fourth circuit boards and the nexus are substantially coplanar, and a second configuration, in which the first, second, third and fourth circuit boards and the nexus are coupled to one another to define a cavity therein.