Electrosurgical Jaw Assembly With Offset Pivot Bar Force Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrosurgical forceps face challenges in providing consistent mechanical and energy-based tissue cutting and dissection, particularly in maintaining a constant closure force and force feel during various tissue dissection and cutting operations.
Innovation Solution
The design incorporates a pivot bar offset from the pivot, secured within cradles of the jaw members, which provides a substantially constant closure force and mechanical advantage, ensuring consistent jaw movement and tissue sealing/cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional pivot mechanism is used in electrosurgical forceps, then the structure is simple, but the closure force varies during the range of motion
Solution Approach 1:
The pivot bar is intentionally offset from the pivot point, creating an asymmetric mechanism. This offset creates a lever arm that provides mechanical advantage and maintains consistent closure force throughout the jaw's range of motion, transforming the force delivery characteristic of the electrosurgical forceps.
Solution Approach 2:
The mechanism dynamically adjusts the force application through the offset pivot bar design. As the jaw closes, the offset geometry automatically maintains optimal mechanical advantage, ensuring consistent closure force from start to finish of the closing stroke without requiring complex active control systems.
2Reliability
If the pivot bar is offset from the pivot, then constant closure force is achieved, but the mechanism complexity increases
Solution Approach 1:
The pivot bar is positioned asymmetrically relative to the pivot point, creating a deliberate offset. This asymmetric configuration is the key design feature that enables consistent sealing pressure throughout the closing motion, transforming the force delivery characteristic of the electrosurgical forceps.
Solution Approach 2:
The offset distance between the pivot and pivot bar is carefully designed to optimize the mechanical advantage ratio. This parameter change transforms the force delivery characteristic, ensuring that closure force remains substantially constant throughout the range of motion rather than varying with the closing stroke.
3Manufacturing precision
If traditional jaw mechanism is used, then manufacturing is easier, but tissue dissection precision is reduced
Solution Approach 1:
The asymmetric offset design of the pivot bar creates superior tissue engagement and cutting precision. The offset geometry provides consistent mechanical advantage that translates to more reliable and precise tissue dissection and cutting performance compared to symmetric traditional mechanisms.
Solution Approach 2:
The offset pivot bar mechanism replaces conventional symmetric pivot mechanisms with an optimized lever-based system. This mechanical substitution improves force delivery consistency, thereby enhancing tissue cutting precision and reliability throughout the closing stroke.
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 offset pivot bar design ensures consistent jaw closure forces and sealing pressures, enhancing tissue dissection and cutting precision, with a uniform feel throughout the handle stroke, reducing tissue catching and improving overall instrument performance.
Implementation Method 1
the offset between the pivot and the pivot bar provides a substantially constant closure force between the first and second jaw members through the range of motion therebetween
Implementation Method 2
electrosurgical forceps utilize both mechanical clamping action and energy to heat tissue to treat, e.g., coagulate, cauterize, dissect or seal, tissue
Data Source
AI summary
An electrosurgical instrument includes a housing having a handle and an elongated shaft extending therefrom supporting an end effector assembly. The end effector assembly includes first and second jaw members each having a jaw housing and an electrically conductive tissue engaging surface. The first jaw member includes a U-shaped proximal flange that defines a cuff having sides configured to support a pivot and also that define cradles for securing a pivot bar. The second jaw member defines a U-shaped cuff for receiving the proximal flange the first jaw member. The cuff includes sides that define cradles for supporting the pivot thereon through the range of motion between first and second jaw members.