Flexible Ball Chain Drive for Stable Articulating Surgical End Effectors

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Solution Overview

Problem

Surgical instruments with articulatable end effectors face challenges in achieving a desired range of articulation while accommodating various drive systems, maintaining locked positions during procedures, and withstanding external forces, especially due to size constraints imposed by trocar cannulas.

Innovation Solution

The surgical instrument employs a firing system with a vertically-extending firing member featuring upper and lower flexible spine assemblies and a rotary drive screw, which includes upper and lower vertebra members with helix-shaped faces for engagement, and a constant velocity drive shaft assembly to facilitate articulation and maintain stability through the articulation joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid drive shaft assembly is used to maintain stable articulation, then articulation stability is improved, but friction and wear increase due to constant contact forces

Engineering Contradiction:

Improvearticulation stabilityVSAvoidfriction and wear

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent employs a flexible spine assembly comprising multiple vertebra members connected by flexible joints, replacing the traditional rigid drive shaft. This flexible structure maintains articulation stability through controlled mechanical coupling while minimizing friction and wear by allowing smooth relative motion between components during articulation movements.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The drive shaft assembly is segmented into multiple vertebra members (e.g., first, second, third vertebra members) that can independently articulate relative to each other. This segmentation allows each segment to handle localized stresses and movements, reducing overall friction and wear while maintaining stable articulation through the coordinated motion of segments.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the size of the drive system is increased to accommodate complex articulation mechanisms, then articulation range is improved, but device size increases beyond trocar cannula constraints

Engineering Contradiction:

Improvearticulation rangeVSAvoiddrive system size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The flexible spine assembly is nested within the elongate shaft assembly, with vertebra members arranged in a compact, space-efficient configuration. The flexible joints and articulation mechanisms are integrated within the existing shaft structure, allowing complex articulation functionality to be achieved without increasing the overall external dimensions of the surgical instrument.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a static, rigid drive shaft to a dynamic flexible spine assembly that can adapt its configuration during articulation. The flexible joints allow the vertebra members to articulate and reconfigure as needed, providing a wide range of motion while maintaining a compact form factor that fits within trocar cannula constraints.

Inventive Principle:

Principle #15Dynamics

3Object-generated harmful factors

If flexible drive components are used to reduce friction, then wear is minimized, but the ability to maintain locked position during procedures deteriorates

Engineering Contradiction:

ImprovewearVSAvoidlocked position stability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The flexible spine assembly incorporates pre-biased flexible joints and vertebra members that are pre-configured to maintain stable articulation positions. The elastic properties of the flexible components provide inherent position-maintaining forces that lock the articulation at desired angles without requiring additional active locking mechanisms, thereby minimizing wear while ensuring procedural stability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes changes in the elastic and mechanical parameters of the flexible spine components to achieve position locking. By carefully designing the stiffness, flexibility, and geometric parameters of the vertebra members and flexible joints, the system can maintain stable locked positions during procedures while still allowing controlled articulation movement when needed.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration allows for precise control and stability of the surgical end effector, enabling effective articulation and maintaining the end effector's position during procedures, reducing friction and wear, and ensuring efficient tissue cutting and stapling.

Implementation Method 1

an articulation joint with a constant velocity drive shaft assembly and elastomeric joint assembly to facilitate precise articulation

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

upper and lower vertebra members with helix-shaped faces for engagement

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Force

Data Source

PatentUS11864756B2Surgical instruments with flexible ball chain drive arrangements

Publication Date: 2024.01.09 CILAG GMBH INTERNATIONAL

AI summary

Surgical instruments that comprise an axially movable firing member that is configured to be driven between a starting position and an ending position within a surgical end effector of the surgical instrument by an upper an upper chain-drive assembly and a lower chain-drive assembly.