Compact Jaw Through Bore Pivot Pin End Effector
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Solution Overview
Problem
Endoscopic electrosurgical forceps designed for small cannulas face design challenges, particularly in actuating the knife blade and preventing rotation, as existing solutions do not adequately address the need for versatile use with various-sized access ports.
Innovation Solution
An end effector assembly with a knife assembly and cam assemblies, featuring a knife blade and actuation shaft that translates through a pivot bore, and cam slots and pins that cooperate to prevent rotation, allowing for precise tissue manipulation and sealing across different cannula sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If endoscopic forceps are designed for small cannulas, then patient benefit (less scarring, less pain) is improved, but device design complexity increases
Solution Approach 1:
The device is divided into separate functional modules: a pivot assembly with bore for receiving the actuation shaft, a knife assembly with blade and actuation shaft, and cam assemblies for actuation. This segmentation allows each component to be optimized independently for use through small cannulas while managing overall design complexity.
Solution Approach 2:
The actuation shaft is received through the pivot bore, and the knife blade is disposed on the actuation shaft. This nested arrangement allows multiple components to occupy overlapping spatial volumes, enabling the device to fit through small cannulas while maintaining all necessary functions.
2Ease of operation
If a through bore pivot is used for knife blade translation, then ease of operation is improved, but knife blade rotation control becomes difficult
Solution Approach 1:
The pivot bore and actuation shaft have non-circular cross-sections that are asymmetric in shape. This asymmetric geometry provides natural mechanical interference that prevents rotational movement of the knife blade while still allowing smooth translational movement through the bore.
Solution Approach 2:
The actuation shaft serves as an intermediary component between the knife blade and the pivot assembly. It transmits the translational motion from the operator while its non-circular cross-section acts as a mechanical key that prevents rotation, mediating between the need for easy translation and rotation control.
3Reliability
If non-circular cross-sections are used for actuation shaft and bore, then knife blade rotation is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The pivot bore and actuation shaft employ non-circular asymmetric cross-sections that provide inherent mechanical interference to prevent rotation. This geometric asymmetry creates natural alignment features that simplify assembly while maintaining manufacturing feasibility through standard machining processes.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An end effector assembly for use with a forceps, the end effector assembly comprising: a pair of jaw members, at least one jaw member moveable relative to the other about a pivot from a first, open position to a second, closed position for grasping tissue, at least one of the jaw members including a knife channel defined therein that extends therealong, the pivot including a bore defined therethrough; a knife assembly including a knife blade and an actuation shaft, the knife blade disposed distally relative to the pivot and the actuation shaft configured for slidable translation through the bore defined in the pivot to allow selective advancement of the knife blade through the knife channel; and at least one cam assembly operably coupled to the at least one moveable jaw member and actuatable to move the at least one jaw member from the first to second position for grasping tissue therebetween.