Forceps Actuation Limiting With Blocking Linkage and Force Cushioning
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Solution Overview
Problem
Conventional medical devices with handpieces that actuate end effectors, such as forceps, face challenges in reducing packaging space, simplifying design and manufacturing, enhancing user experience, increasing stability, and preventing damage.
Innovation Solution
The development of a medical device with a handpiece that includes an actuation system allowing for the control of end effectors to be rotatable, openable, closeable, extendable, and capable of supplying electromagnetic energy, featuring a drive shaft motion transfer assembly with a force-limiting spring and clip to prevent damage by limiting excessive force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional forceps actuation systems are used, then the design is simple, but excessive force can damage the forceps or tissue
Solution Approach 1:
A spring-loaded cam mechanism is incorporated into the actuation system that provides force limiting before excessive force can be applied. The cam follows a predetermined path that inherently limits the maximum force transmitted to the forceps jaws, cushioning against potential damage while maintaining actuation functionality.
Solution Approach 2:
The cam mechanism acts as an intermediary between the actuator and the forceps jaws. It mediates the force transmission by following a constrained path that limits peak forces, thereby protecting the system from damage while still enabling effective actuation of the jaws.
2Adaptability or versatility
If the actuation system allows full range of motion, then the end effector is versatile, but packaging space increases
Solution Approach 1:
The cam mechanism is nested within the existing actuation system architecture, with the cam follower and cam surface integrated into the motion transfer pathway. This nested arrangement enables the cam to control the motion path without requiring separate housing or additional space, maintaining compact packaging while providing force limiting functionality.
3Reliability
If the cam mechanism is added for force limiting, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The cam mechanism is merged with the existing motion transfer components of the actuation system. The cam and cam follower are integrated into the same assembly that transfers motion from the actuator to the forceps jaws, combining multiple functions (motion transfer and force limiting) into a unified structure that simplifies manufacturing compared to separate components.
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 solution improves the user experience by enhancing stability, reducing the risk of damage to the forceps, and simplifying the design and manufacturing process while allowing for efficient actuation of end effectors.
Implementation Method 1
a force-limiting spring positioned around the drive shaft between the drive body and the clip
Data Source
AI summary
Medical devices include a ground link, a first actuator pivotably coupled to the ground link and a first movable element operatively coupled to the first actuator by a linkage. The linkage including: the ground link; a second link that is pivotable with respect to the ground link; a fourth link that is pivotable with respect to the ground link; and a third link having a main body extending from a first portion to a second portion and a blocking tab extending away from the main body. The medical device further including a second actuator operatively coupled to the ground link, the second actuator having a blocking surface including a blocking tab that is positioned to engage with at least a portion of the blocking surface of the second actuator to limit movement of the second actuator until the first actuator is at least partially actuated.