Monolithic End-Effector Knife Assembly for Improved Sealing

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Solution Overview

Problem

Existing end effectors in minimally invasive surgical instruments face challenges in knife design and functionality, affecting efficiency and manufacturability, particularly in robotic surgical systems where the knife assembly requires additional components and larger cross-sectional areas that compromise sealing performance.

Innovation Solution

A monolithic knife assembly is integrated with a drive rod and knife blade formed from a single piece of material, reducing the cross-sectional area at the hinge portion and eliminating separate components like ferrules, allowing for a smaller knife slot and improved sealing surfaces while enhancing manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional knife assemblies with separate components (blade, ferrule, drive rod) are used, then the knife can be manufactured and assembled, but the cross-sectional area at the hinge portion increases and sealing performance deteriorates

Engineering Contradiction:

Improvesealing performanceVSAvoidknife assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the blade, ferrule, and drive rod into a single monolithic knife assembly manufactured as one piece. This integration eliminates the need for separate components and assembly operations, directly reducing the cross-sectional area at the hinge portion while maintaining structural integrity and improving sealing performance.

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If multiple separate components are used in the knife assembly, then manufacturing flexibility exists, but assembly steps are required and manufacturing efficiency decreases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidassembly process

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The monolithic knife assembly is manufactured as a single integrated component, eliminating all assembly steps. This approach directly improves manufacturing efficiency and productivity by reducing the number of operations required while maintaining design flexibility through modern manufacturing techniques.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If a larger cross-sectional area is used in the knife assembly, then structural strength is maintained, but the knife slot size increases and sealing surface area is reduced

Engineering Contradiction:

Improveknife assembly strengthVSAvoidsealing surface area

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The integrated monolithic design allows for optimized cross-sectional geometry that maintains sufficient structural strength while minimizing the overall size. The single-piece construction eliminates the need for additional reinforcement from separate components, enabling a smaller knife slot and larger sealing surface area.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250325294A1Knife designs for end effectors used in surgical tools

Publication Date: 2025.10.23 CILAG GMBH INTERNATIONAL

AI summary

An end effector of a surgical tool includes opposing first and second jaws, a knife slot defined in one or both of the first and second jaws, and a monolithic knife assembly comprising a drive rod and a blade distally extending from the drive rod and extendable through the knife slot, the drive rod and the blade made from a same material.