Endoscopic Forceps Handle Pivot Pin Positioning

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Solution Overview

Problem

Endoscopic electrosurgical forceps face challenges in consistently sealing larger vessels due to the need for precise control of closure force and gap distance between electrodes, which is difficult to achieve with existing designs, leading to variability in seal quality and potential mechanical failure.

Innovation Solution

The design of an endoscopic bipolar forceps with a unique handle assembly and end effector assembly that provides a mechanical advantage for consistent closure force, featuring a movable handle with pivot pins positioned above the driving flange, a rotating assembly, and a knife channel mechanism to ensure precise tissue sealing and cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large closure force is applied to seal larger vessels, then the sealing effectiveness is improved, but the risk of mechanical failure (pin shearing) increases

Engineering Contradiction:

Improvesealing effectivenessVSAvoidmechanical strength of pins

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The pivot pins are positioned above the driving flange, creating a dynamic mechanical advantage system where the moment arm varies during jaw closure. This dynamic positioning allows the system to generate sufficient closure force for sealing while distributing mechanical stress to prevent pin shearing

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameters of the handle assembly, specifically positioning the pivot pins at a location that provides optimal moment arm length. This parameter change enables the system to achieve the required closure force (3-16 kg/cm²) without exceeding the mechanical strength limits of the pins

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the pivot pins are positioned to provide small moment arms, then the device complexity is reduced, but the closure force capability is insufficient for sealing larger vessels

Engineering Contradiction:

Improvehandle assembly complexityVSAvoidclosure force

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The pivot pins are positioned in a different spatial dimension relative to the driving flange—specifically above it rather than at the conventional pivot point. This dimensional repositioning creates a longer moment arm that increases closure force capability without adding complex mechanical components

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If metal pivot pins are used to provide structural support, then the mechanical strength is improved, but electrical insulation must be added to prevent alternate current paths

Engineering Contradiction:

Improvestructural strengthVSAvoidelectrical insulation requirements

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The pivot pins serve as a mechanical intermediary that transfers force while the handle assembly structure provides electrical insulation. The insulating material in the handle assembly acts as an intermediary barrier that prevents electrical current from traveling through the metal pins, eliminating the need for additional insulation on the pins themselves

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The forceps achieve consistent tissue sealing within the desired pressure range of 3 kg/cm2 to 16 kg/cm2, reducing the risk of mechanical failure and improving the quality of tissue seals, allowing for effective sealing and cutting of larger vessels without the need for open-surgical procedures.

Implementation Method 1

Each of the jaw members is adapted to connect to an electrosurgical energy source, thus enabling the jaw members to conduct energy through tissue held between the jaw members to create a tissue seal

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

Each of the jaw members is adapted to connect to an electrosurgical energy source, thus enabling the jaw members to conduct energy through tissue held between the jaw members

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS9655675B2Vessel sealer and divider

Publication Date: 2017.05.23 COVIDIEN LP

AI summary

An endoscopic bipolar forceps includes a housing and a shaft, the shaft having an end effector assembly at a distal end thereof, which includes two jaw members for grasping tissue therebetween. Each jaw member is adapted to connect to an electrosurgical energy source, enabling them to affect a tissue seal to tissue held therebetween. A drive assembly is included within the housing for moving the jaw members. A movable handle is also included, such that movement of the handle actuates the drive assembly to move the jaw members relative to each other. A knife channel is included within the end effector configured to allow reciprocation of a knife blade within the knife channel. The knife blade includes a proximal edge adapted to engage a proximal edge of the end effector to impede translation of the knife blade when the jaw members are in an open configuration and the knife blade is retracted within the end effector assembly.