Trocar Seal Assembly Segmented Woven Design
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Solution Overview
Problem
Current trocar seal assemblies face issues with hoop stress and tearing when large diameter instruments are inserted, leading to increased resistance and potential seal failure due to the need for small diameter lip seals that are stretched beyond their limits.
Innovation Solution
A seal assembly composed of multiple overlapping semicircular seal segments with vertical walls, assembled in a woven arrangement to provide a complete seal body without a secondary seal, reducing hoop stresses and allowing for greater expansion and material flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a small diameter lip seal is used to seal around instruments of various sizes, then the seal can accommodate a full range of instrument sizes, but the seal is pushed to excessive strain (up to 400%) causing increased drag and resistance to instrument insertion
Solution Approach 1:
The seal is divided into multiple segments (typically four) that can independently expand and contract. Each segment contains a sealing element that can deform to accommodate instruments of various diameters without requiring the entire seal to be stretched to extreme strains, thereby reducing insertion resistance while maintaining versatility across instrument sizes.
2Adaptability or versatility
If a small diameter lip seal is stretched to accommodate large diameter instruments, then the seal can seal around larger instruments, but the seal material is subjected to excessive hoop stress causing tearing and seal failure
Solution Approach 1:
By segmenting the seal structure, each individual sealing element experiences significantly reduced hoop stress compared to a single continuous seal stretched to the same diameter. The stress is distributed across multiple segments, preventing any single point from experiencing excessive tension that would lead to tearing or failure.
Solution Approach 2:
The seal segments are designed to dynamically expand and contract as instruments are inserted and removed. This dynamic behavior allows the seal to adapt to different instrument diameters without being permanently stretched, maintaining material integrity and preventing tearing even when accommodating large diameter instruments.
3Device complexity
If a single seal assembly is used instead of a double sealing system, then the overall complexity of the trocar assembly is reduced, but the seal must provide both instrument sealing and housing sealing functions
Solution Approach 1:
The segmented seal assembly is designed to perform multiple functions: it seals around instruments during insertion and removal, seals the trocar housing when no instrument is present, and maintains sealing across a full range of instrument diameters. This multi-functional design eliminates the need for separate top and duckbill seals, reducing overall system complexity while maintaining comprehensive sealing capability.
Data Source
AI summary
A seal assembly adapted for use in conjunction with a trocar assembly includes a plurality of seal segments, each seal segment including a peripheral edge and a seam edge. Each seal segment further includes a first section and a second section with a vertical wall connecting the first section and the second section in such a way that the first section is displaced relative to the second section such that the first section of a first seal segment may be placed upon the second section of a second seal segment with the first sections of the first and second seal segments lying in the same plane and the second sections of the first and second seal segments lying in the same plane. The seal segments are assembled in an overlapping woven arrangement to provide a complete seal body without the need for a secondary seal.