Spring-Assisted Sealing Instrument for Controlled Jaw Force
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Solution Overview
Problem
Surgical instruments used in robotic systems face challenges in controlling closure and sealing forces between jaw members to prevent tissue and instrument damage, necessitating effective force monitoring and management.
Innovation Solution
The surgical instrument incorporates a spring mechanism with a variable spring rate or a progressive spring to offload forces on the drive rod or knife tube, allowing controlled force application and preventing damage by distributing forces before full compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rigid drive rod is used to actuate the jaw members, then the force transmission is efficient and direct, but the risk of tissue damage and instrument damage increases due to uncontrolled force application
Solution Approach 1:
A spring mechanism is integrated into the drive assembly to provide force buffering before the drive rod directly actuates the jaw members. The spring absorbs excess force during jaw closure, preventing both tissue damage and instrument damage while maintaining efficient force transmission throughout the actuation cycle
Solution Approach 2:
The drive assembly incorporates a variable spring rate mechanism that changes the stiffness parameter during actuation. The spring rate is lower during initial jaw closure to prevent tissue damage, and increases as the jaw members approach full closure to maintain effective sealing force
2Object-affected harmful factors
If the spring is designed with a low spring rate to reduce force on the drive rod, then tissue damage is prevented, but the sealing force may be insufficient for proper tissue treatment
Solution Approach 1:
The spring mechanism is designed with a progressive spring rate that dynamically changes during actuation. The spring rate is lower during initial jaw closure to prevent tissue damage, and increases as the jaw members approach full closure to maintain effective sealing force for proper tissue treatment
Solution Approach 2:
The drive assembly incorporates a variable spring rate mechanism that changes the stiffness parameter during actuation. The spring rate is lower during initial jaw closure to prevent tissue damage, and increases as the jaw members approach full closure to maintain effective sealing force
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 spring mechanism effectively manages forces, ensuring safe and controlled tissue grasping and cutting, reducing the risk of damage to the instrument and tissue, while maintaining precise control over jaw movement and cutting operations.
Implementation Method 1
A spring having a spring rate 'k' is operably associated with the drive rod and is configured to offload forces associated therewith during actuation of the drive rod
Implementation Method 2
The spring includes a first length wherein adjacent coils of the spring are spaced a distance relative to one another such that the spring offloads forces associated with the drive rod as per the spring rate 'k' of the spring
Data Source
AI summary
A surgical instrument includes a housing having a shaft extending therefrom with an end effector at a distal end thereof. The end effector includes first and second jaw members moveable between a spaced apart configuration and a closed position to grasp tissue between jaw members. A drive assembly including a drive rod is associated with the movable jaw member. A spring having a spring rate “k” is operably associated with the drive rod and is configured to offload forces associated therewith during actuation thereof. The spring includes a first length wherein adjacent coils thereof are spaced a distance relative to one another such that the spring offloads forces associated with the drive rod as per the spring rate “k” of the spring and a fully compressed length wherein the adjacent coils of the spring abut one another and the forces associated with the drive rod are transferred through the spring.