Knife Return Blade Assembly for Stable Vessel Sealer Transection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrosurgical instruments struggle to consistently seal and transect tissue without excessive movement of the cutting element, leading to ineffective seals and thermal spread to adjacent tissue.

Innovation Solution

A blade assembly with a blade channel and camming slots, utilizing blade springs and a blade cam, minimizes movement by providing a predetermined cutting path, ensuring consistent transection and reduced thermal spread.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a blade is used to cut tissue in existing electrosurgical instruments, then tissue transection is achieved, but the blade moves excessively during cutting leading to inconsistent seals and thermal spread to adjacent tissue

Engineering Contradiction:

Improvecutting precisionVSAvoidthermal spread

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a blade guide as an intermediary component between the blade and the jaw members. This guide constrains the blade's movement path, ensuring it moves precisely along the intended cutting trajectory without excessive lateral motion. The blade guide acts as a mediator that translates the actuation force into controlled linear blade movement, thereby preventing thermal spread to adjacent tissue while maintaining effective tissue transection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the movement parameters of the blade by implementing a constrained linear path through the blade guide. Instead of allowing free or arcuate movement, the blade is restricted to move only in the intended cutting direction with controlled displacement. This parameter change in blade movement trajectory and limits thermal spread while maintaining cutting effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If clamping pressure alone is used to control seal thickness, then sealing is achieved, but it is difficult to control the thickness consistently due to force application variability

Engineering Contradiction:

Improveseal thickness consistencyVSAvoidforce control difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces the reliance on operator-applied clamping pressure with a mechanically-driven blade actuation system. The blade is moved into the tissue by a controlled mechanical actuation mechanism rather than by manual pressure application. This substitution eliminates the variability associated with human force control and provides consistent, repeatable cutting depth and seal thickness through precise mechanical actuation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the blade is moved longitudinally to cut tissue, then tissue transection is achieved, but lengthy movement causes undesirable movement of the cutting element and end effector assembly

Engineering Contradiction:

Improvecutting efficiencyVSAvoidend effector stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent extracts the cutting function from the overall end effector assembly movement. Instead of moving the entire end effector assembly longitudinally to achieve cutting, only the blade itself is moved within the constrained path of the blade guide. This separation allows the end effector assembly to remain stable and stationary while the blade performs the cutting action locally, thereby maintaining assembly stability while achieving efficient tissue transection.

Inventive Principle:

Principle #2Taking out (Extraction)

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 blade assembly enables precise and efficient tissue transection with minimal movement, enhancing seal consistency and reducing collateral thermal damage.

Implementation Method 1

the blade including one or more blade springs operably associated therewith configured to bias the blade within the blade channel

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the blade cam including a series of camming surfaces configured to operably engage the corresponding series of camming slots of the blade, the blade cam including a proximal end operably coupled to an actuation rod configured to move the blade cam upon movement thereof

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP4147653B1Cutting blade for vessel sealer with knife return

Publication Date: 2025.12.31 COVIDIEN LP

Figure 1A
Figure 1B
Figure 2A~2C

AI summary

A forceps includes a pair of jaw members movable relative to one another, one of the jaw members defining a blade channel therein configured to house a cutting mechanism. The cutting mechanism includes: a blade having camming slots defined along a length thereof and one or more blade springs operably associated therewith configured to bias the blade within the blade channel; and a blade cam including camming surfaces configured to operably engage the corresponding camming slots of the blade. The blade cam includes a proximal end operably coupled to an actuation rod configured to move the blade cam upon movement thereof. The actuation rod, upon movement thereof, moves the camming surfaces of the blade cam into engagement against the camming slots forcing the blade into the blade channel against the bias of the biasing spring to cut tissue therebetween.