Surgical Adapter Cam Mechanism for Articulation Control
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Solution Overview
Problem
Endoscopic surgical instruments face challenges in articulating their end effectors due to bending moments and shear forces that can inadvertently drive knife shafts forward, leading to premature cutting or stapling during limited access procedures.
Innovation Solution
An adapter assembly with a cam housing and elongate shafts that articulate the surgical loading unit by translating relative to the cam housing, using opposing cam slots with different pitches and helical configurations to counteract any inadvertent translation of the knife rod, ensuring synchronized movement with the end effector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the end effector is articulated during surgical procedures, then access to tissue is improved, but the knife shaft experiences bending moments and shear forces that may inadvertently drive the knife shaft forward
Solution Approach 1:
The cam mechanism is designed to apply a counteracting force to the knife shaft that prevents inadvertent forward movement during end effector articulation. The cam slot geometry creates a mechanical constraint that actively resists the bending moments and shear forces generated during articulation, thereby preventing premature cutting or stapling while allowing the desired articulation motion.
Solution Approach 2:
The cam and cam slot assembly acts as an intermediary mechanism between the articulation motion and the knife shaft. This intermediate mechanism translates the articulation motion while simultaneously controlling the longitudinal position of the knife shaft, decoupling the articulation degree of freedom from the cutting action to prevent unintended activation.
2Ease of operation
If the surgical loading unit is articulated relative to the adapter assembly, then access in confined surgical sites is improved, but maintaining alignment between the surgical loading unit and knife rod becomes more difficult
Solution Approach 1:
The system employs a dynamic cam mechanism where the cam slot geometry is specifically designed to maintain proper alignment between the surgical loading unit and knife rod during articulation. As the end effector articulates, the cam mechanism dynamically adjusts the longitudinal position of the surgical loading unit relative to the adapter assembly, ensuring that alignment is preserved throughout the range of motion rather than being fixed in a static configuration.
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
This solution allows for precise articulation of the surgical loading unit, preventing premature cutting or stapling by ensuring the surgical loading unit translates with the knife rod, maintaining alignment and improving access in confined surgical sites.
Implementation Method 1
an adapter assembly with a cam housing and elongate shafts that articulate the surgical loading unit by translating relative to the cam housing
Data Source
AI summary
An adapter assembly includes a cam housing defining a proximal cam slot and a distal cam slot, a first elongate shaft, and a second elongate shaft. The first elongate shaft has a proximal end portion received in the proximal cam slot, and a distal end portion configured to be coupled to a surgical loading unit. The second elongate shaft has a proximal end portion received in the distal cam slot, and a distal end portion configured to be coupled to the surgical loading unit. The first and second elongate shafts are configured to move in opposing longitudinal directions in response to a rotation of the cam housing to articulate the surgical loading unit.