Trocar Gearbox for Disposable Minimally Invasive Surgery
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Solution Overview
Problem
Existing trocars used in robot-assisted minimally invasive surgeries are not suitable for design as inexpensive, disposable components due to complex couplings that fail to ensure sterility and functional versatility.
Innovation Solution
A trocar with an internal instrument drive mechanism, including a transversely arranged input shaft and a gearbox within the trocar housing, converts rotational movement from an external drive source into translational movement of the surgical instrument, allowing for a simple, cost-effective, and sterile interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex coupling mechanism is used to connect the trocar to the robot arm, then the transmission of driving force is improved, but the device complexity and cost increase, making it unsuitable for disposable components
Solution Approach 1:
The coupling mechanism is divided into two separate parts: a coupling element on the robot arm side and a coupling receptacle on the trocar side. This segmentation allows the complex driving force transmission function to be achieved while keeping each individual component simple and suitable for disposable use.
Solution Approach 2:
The coupling element acts as an intermediary component that bridges the robot arm and trocar. It includes a drive shaft with a drive interface that connects to the robot arm's drive source, and a coupling receptacle that receives the trocar, thereby transmitting driving force without requiring a complex integrated coupling structure.
2Reliability
If the trocar is designed as a single-use disposable component, then sterility is improved, but the cost increases and functional versatility decreases
Solution Approach 1:
The expensive and complex drive source is extracted from the disposable trocar and placed on the reusable robot arm side. The trocar itself is simplified to contain only the necessary coupling receptacle and instrument drive mechanism, making it inexpensive to manufacture as a disposable component while maintaining sterility.
Solution Approach 2:
The trocar is designed as a cheap, disposable component that can be sterilized and discarded after single use. By removing the expensive drive source from the trocar and placing it on the reusable robot arm, the trocar becomes economically viable as a single-use item while ensuring sterility through disposable design.
3Ease of manufacture
If the drive source is located in the robot arm instead of the trocar, then the trocar can be designed as disposable, but the coupling interface becomes more complex
Solution Approach 1:
The coupling interface is segmented into a drive shaft with drive interface on the robot arm side and a coupling receptacle on the trocar side. This segmentation simplifies the overall coupling complexity by distributing the coupling function across two separate, manageable components rather than requiring a complex integrated interface.
Solution Approach 2:
The coupling element is designed with multi-functionality: it serves as both the drive transmission mechanism and the mechanical coupling interface between the robot arm and trocar. The drive shaft provides both rotational drive transmission and positional coupling, reducing the need for separate coupling components.
4Ease of operation
If a simple coupling interface is used, then ease of connection is improved, but the transmission of driving force and functional versatility deteriorate
Solution Approach 1:
The coupling element serves as an intermediary that provides both simple connection and reliable drive transmission. The coupling receptacle on the trocar side provides a simple receptacle for receiving the drive shaft, while the drive shaft itself provides the reliable mechanical connection for driving force transmission through its engagement with the robot arm's drive source.
Data Source
AI summary
A trocar comprising a trocar housing, a drive unit designed and configured to move the surgical instrument, a coupling unit designed and configured to couple and uncouple the drive unit to and from an external drive source, the coupling unit comprising an input shaft being supported by the trocar housing, the input shaft being designed and configured to be driven by the drive source, and a transmission/gearbox designed and configured to convert a rotational movement of the input shaft about the longitudinal input shaft axis into a translational movement of the surgical instrument within to the trocar along a longitudinal trocar direction. Also provided is a minimally invasive surgical device equipped with this trocar.