Asymmetric Pivot Mechanism for Surgical Stapler Jaws
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Solution Overview
Problem
Surgical stapling devices require frequent replacement of staple cartridges during endoscopic or laparoscopic procedures, necessitating removal and reinsertion of the device through small incisions, which is cumbersome and inefficient.
Innovation Solution
A pivot mechanism comprising a first jaw member with circular apertures and a second jaw member with square-like apertures, along with a pivot pin that engages both, allowing for secure and robust pivotal connection between the cartridge and anvil assemblies, facilitating easier assembly and operation while reducing the force required for installing and removing the pivot pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pivot connection is used between cartridge and anvil assemblies, then the device structure is simple, but the connection is not secure enough and requires frequent cartridge replacement
Solution Approach 1:
The patent employs asymmetric aperture designs where the cartridge assembly has a circular aperture and the anvil assembly has a square-like aperture. The pivot pin features a cylindrical body portion that fits the circular aperture and a square-like tip that fits the square-like aperture. This asymmetric geometry creates a secure, non-circular connection that prevents rotation and ensures reliable coupling between assemblies.
Solution Approach 2:
The pivot pin is designed with different geometric features at different locations: a cylindrical body portion for engagement with the circular aperture in the cartridge assembly, and a square-like tip for engagement with the square-like aperture in the anvil assembly. This local differentiation of geometric properties ensures optimal fit and connection security at each interface.
2Productivity
If a secure pivot connection is implemented, then cartridge replacement frequency is reduced, but the assembly and disassembly process becomes more complex
Solution Approach 1:
The asymmetric aperture and pivot pin design provides inherent alignment features that guide the assembly process. The circular aperture aligns with the cylindrical body portion, and the square-like aperture aligns with the square-like tip, making the assembly process intuitive and reducing complexity despite the secure connection requirement.
Solution Approach 2:
The pivot pin is segmented into distinct functional portions: a cylindrical body portion for cartridge engagement and a square-like tip for anvil engagement. This segmentation allows each portion to be optimized for its specific engagement requirement while simplifying the overall assembly process through modular geometry.
3Force
If a robust pivot pin connection is used, then the force required for installation and removal is reduced, but the pivot pin structure becomes more complex
Solution Approach 1:
The asymmetric geometry of the pivot pin with its cylindrical body and square-like tip creates mechanical advantage during installation and removal. The non-circular engagement provides natural alignment and reduces the force needed to insert and extract the pivot pin, while the structural complexity remains minimal due to the straightforward geometric forms.
Solution Approach 2:
The pivot pin features localized geometric variations: a cylindrical body portion for smooth engagement with the circular aperture and a square-like tip for secure engagement with the square-like aperture. This local differentiation of geometric properties optimizes the force characteristics at each interface without requiring complex overall structure.
Data Source
AI summary
A pivot mechanism for use with a surgical device includes a first jaw member, a second jaw member, and a pivot pin. The first jaw member includes at least one circular aperture. The second jaw member includes at least one square-like aperture. The pivot pin is configured to engage the at least one circular aperture of the first jaw member and the at least one square-like aperture of the second jaw member such that the first jaw member is pivotably coupled to the second jaw member.