Nested Gear Articulation Joint for Precise Surgical End Effector Control

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Solution Overview

Problem

Existing surgical staplers require complex mechanisms to articulate the end effector relative to the elongate shaft, which can be cumbersome and limit precise positioning during surgical procedures.

Innovation Solution

The surgical instrument features a compact articulation joint with a nested gear assembly, allowing for precise articulation and rotation of the end effector while maintaining the ability to transfer rotary control motions, thereby enhancing user dexterity and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a complex articulation mechanism is used to articulate the end effector relative to the elongate shaft, then the end effector can be positioned and oriented properly within the body cavity, but the device complexity increases and user dexterity is limited

Engineering Contradiction:
Improveuser dexterityVSAvoidarticulation mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs a nested gear assembly where a first gear is positioned within a second gear, and a third gear is positioned within the first gear. This nested configuration allows multiple articulation functions to be integrated in a compact space, reducing the overall complexity of the articulation mechanism while maintaining the ability to properly position and orient the end effector within the body cavity during surgical procedures.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If the articulation mechanism is simplified to reduce device complexity, then ease of operation improves, but the ability to transfer rotary control motions accurately deteriorates

Engineering Contradiction:
Improvearticulation mechanism complexityVSAvoidcontrol motion transfer precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The nested gear assembly enables accurate transfer of rotary control motions from the handle to the end effector while maintaining a compact and simple overall structure. The interlocking teeth of the nested gears ensure precise motion transmission without requiring complex mechanisms, thus resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The gear assembly acts as an intermediary mechanism that translates rotary control motions from the handle into the desired articulation movements of the end effector. The nested gear configuration provides a compact transmission path that maintains control precision while simplifying the overall articulation mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the distance between the articulation axis and the end effector is minimized to improve positioning precision, then user control and precision are enhanced, but the device design becomes more constrained

Engineering Contradiction:
Improveend effector positioning precisionVSAvoiddevice design flexibility
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The nested gear assembly allows the articulation mechanism to be positioned closer to the end effector by compacting the gear train into a nested configuration. This reduces the distance between the articulation axis and the end effector, enhancing positioning precision while the modular nested design maintains manufacturing flexibility through standardized gear components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3449850B1Rotary powered articulation joints for surgical instruments
Publication Date: 2025.06.04 ETHICON INC
  • EP3449850B1 patent drawingFigure 1
  • EP3449850B1 patent drawingFigure 2
  • EP3449850B1 patent drawingFigure 3

AI summary

An articulation joint for a surgical instrument. In at least one form, the articulation joint includes a proximal joint portion that is coupled to an elongate shaft assembly of the surgical instrument. A distal joint portion is movably coupled to the proximal joint portion and is configured to interface with a surgical end effector. A first gear train operably interfaces with a proximal firing shaft segment within the elongate shaft assembly and a distal firing shaft segment that is configured to operably interface with the surgical end effector for transmitting a rotary firing motion thereto from the proximal firing shaft segment to the surgical end effector. A second gear train operably interfaces with a proximal rotation shaft portion of the elongate shaft assembly for transmitting a distal rotational control motion to the surgical end effector to cause the surgical end effector to rotate relative to the elongate shaft assembly while facilitating articulation of the distal joint portion relative to the proximal joint portion.