Cam Driver Alignment in Surgical Instrument Jaw Mechanism
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Solution Overview
Problem
Designing surgical instruments for robotic surgical systems poses challenges in utilizing available inputs and maintaining proper alignment of moving parts to ensure reliable and safe operation.
Innovation Solution
A surgical instrument with a gearbox assembly and end effector assembly that includes a cam mechanism, where a cam driver and cam bar operate within a defined space to pivot jaw members between open and closed positions, maintaining alignment and enabling precise tissue grasping and cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a robotic arm provides inputs to a surgical instrument, then the surgical instrument can be operated, but the number and type of inputs constrain the design of the surgical instrument
Solution Approach 1:
The surgical instrument is divided into modular components including a robotic arm interface, gearbox assembly, and end effector assembly. This segmentation allows each module to be independently designed and optimized while maintaining compatibility with the robotic arm's input constraints.
Solution Approach 2:
The gearbox assembly is designed to perform multiple functions: transmitting rotational motion from the robotic arm, converting it to linear motion via the cam mechanism, and providing mechanical advantage. This multi-functionality reduces the number of separate components needed.
2Reliability
If moving parts of the surgical instrument are designed for reliable operation, then proper alignment must be maintained, but this increases design complexity
Solution Approach 1:
The cam mechanism employs curved cam slots and rounded cam surfaces that naturally guide the motion of the cam follower. This curvature provides self-aligning characteristics that maintain proper alignment of moving parts throughout the operation cycle, reducing the need for complex alignment mechanisms.
Solution Approach 2:
The cam driver acts as an intermediary element between the rotational input from the robotic arm and the linear motion required by the end effector. It mediates the motion transmission while maintaining alignment through its cam profile geometry, simplifying the overall alignment requirements.
3Reliability
If a cam mechanism is used to pivot jaw members, then proper alignment is maintained, but the device complexity increases
Solution Approach 1:
The cam driver and cam slot are integrated into a single coordinated mechanism where the cam driver's profile directly engages with the cam slot in the jaw member. This merging of functions reduces the number of separate components compared to using separate guides and actuators.
Solution Approach 2:
The cam mechanism is designed to self-align and self-regulate the motion of the jaw members. The geometric constraints of the cam profile automatically maintain proper alignment without requiring additional alignment mechanisms or complex control systems.
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 cam mechanism ensures proper alignment and efficient operation of the surgical instrument, allowing for reliable and safe grasping and cutting of tissue, while accommodating the constraints of robotic surgical systems.
Implementation Method 1
A cam driver is operably coupled to the proximal flange of the first jaw member to define a space between the cam driver and the proximal flange of the first jaw member. A cam bar is operably coupled to the drive rod and disposed within the space defined between the cam driver and the proximal flange of the first jaw member. The cam bar includes a cam pin configured to move within a cam slot of the cam driver to move the first jaw member relative to the second jaw member between the open position and the closed position.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An end effector assembly includes first and second jaw members movable between an open and closed position to grasp tissue therebetween. First and second proximal flanges extending proximally from the second jaw member and defining a space therebetween, a proximal flange (4210) extend proximally from a proximal portion of the first jaw member and define a cam slot (4210s). A cam driver (5210) operably is coupled to the proximal flange (4210) of the first jaw member to define a space between the cam driver and the proximal flange of the first jaw member. A cam bar is disposed within the space defined between the cam driver and the proximal flange of the first jaw member. The cam bar includes a cam pin configured to move within a cam slot (5210s) of the cam driver to move the first jaw member relative to the second jaw member between the open position and the closed position.