Electrosurgical Forceps Cam Jaw Actuation Friction Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Electrosurgical forceps face issues with frictional losses and reduced operational life due to shaft bending or deformation, which impede the effective transfer of closure force to jaw members, affecting tissue sealing and instrument longevity.

Innovation Solution

The design incorporates a resilient member and cam slots in the jaw members, allowing for a consistent closure force and reduced frictional losses by biasing the jaw members in the clamping position, with cam slots and detents facilitating movement between open and clamping positions, and stop members maintaining uniform distance for tissue sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a drive rod is used to translate through the shaft to actuate jaw members, then mechanical force can be transmitted to close the jaw members, but frictional losses increase when the shaft bends or deforms, reducing the effective closure force at the jaw members

Engineering Contradiction:

Improveclosure forceVSAvoidfrictional losses

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The patent replaces the traditional drive rod translation mechanism with a cam-based rotational mechanism. The cam member rotates within cam slots defined in the jaw members, converting rotational motion into the desired jaw closure movement. This substitution eliminates the need for linear translation through the shaft, thereby eliminating frictional losses associated with drive rod movement through bent shafts.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of translating the drive rod linearly through the shaft to close the jaw members, the invention inverts the mechanism by using rotational cam motion to achieve the same jaw closure effect. The cam member's rotation within the cam slots produces the closing force, reversing the traditional approach of linear drive rod movement.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If the shaft is bent or deformed during the procedure, then mechanical advantage can be gained at the surgical site, but frictional losses increase and diminish the operative life of the spring and instrument

Engineering Contradiction:

Improvemechanical advantageVSAvoidinstrument life

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the friction-prone drive rod translation system with a cam-based rotational system that is insensitive to shaft bending. The cam member rotates within cam slots, providing reliable mechanical advantage at the surgical site without the frictional losses that would otherwise diminish instrument life when the shaft is bent or deformed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If small jaw members are used to pass through small openings, then the instrument can access tight surgical sites, but the shaft and drive components must be proportioned smaller, increasing frictional losses

Engineering Contradiction:

Improveaccess to surgical sitesVSAvoidfrictional losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent replaces the traditional small-scale drive rod mechanism with a cam-based rotational system that maintains effectiveness even with proportionally smaller components. The cam member rotating within cam slots provides sufficient mechanical advantage for small jaw members to achieve effective closure force, eliminating the increased frictional losses that would result from using smaller translation components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 ensures consistent tissue sealing with reduced frictional losses and extended instrument life by maintaining closure force and mechanical advantage, even with shaft bending or deformation.

Implementation Method 1

A resilient member is operably coupled to one or both of the jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

One of the first and second jaw members includes one or more cam slots defined therein and is configured to receive a cam member that upon movement thereof rotates the jaw members from the clamping position to the open position.

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentUS11957402B2Apparatus for performing an electrosurgical procedure

Publication Date: 2024.04.16 COVIDIEN LP

AI summary

A forceps includes a housing having a shaft. An end effector assembly operatively connects to a distal end of the shaft and includes a pair of first and second jaw members. One or both of the first and second jaw members is movable relative to the other jaw member from a clamping position to an open position. A resilient member operably couples to the first and second jaw members. The resilient member is configured to bias the first and second jaw members in the clamping position and provide a closure force on tissue disposed therebetween.