Surgical Instrument Gear Drive With Variable Mechanical Advantage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Surgical instruments often require varying mechanical advantages based on their functions, which existing gear drive mechanisms with constant or geometrically increasing mechanical advantages fail to adequately address, leading to suboptimal performance in tasks such as tissue compression and surgical clip deployment.
Innovation Solution
A gear drive mechanism featuring a variable-radius third gear, also known as a nautilus gear, which provides different mechanical advantages during a single actuation stroke by having two distinct radii, allowing for a reduced force requirement while ensuring adequate advancement of the drive member for surgical tasks, comprising a first gear on the movable handle, a second gear within the housing, a third gear with variable radii, and a fourth gear in mechanical cooperation with the drive member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a simple pivoted handle with constant mechanical advantage is used, then the structure is simple and easy to manufacture, but it cannot provide varying mechanical advantage needed for different surgical functions
Solution Approach 1:
The patent applies the dynamics principle by implementing a variable mechanical advantage system through a multi-gear mechanism where the movable handle can achieve different mechanical advantage ratios (first mechanical advantage ratio and second mechanical advantage ratio) depending on the position and engagement of the gears. This allows the system to transition from a static, constant mechanical advantage to a dynamic, variable mechanical advantage system that adapts to different surgical functions.
Solution Approach 2:
The patent applies the parameter changes principle by varying the mechanical advantage parameter throughout the actuation stroke. The system transitions between different mechanical advantage ratios by engaging different gear combinations, allowing the mechanical advantage to change as a function of the handle's position and the surgical task requirements.
2Force
If a handle with geometrically increasing mechanical advantage is used, then force is increased for tissue compression or clip deployment, but the force requirement is still not optimized for all surgical functions
Solution Approach 1:
The system uses a movable handle that can dynamically adjust its mechanical advantage ratio based on the surgical function being performed. By engaging different gear combinations (first gear ratio for initial actuation, second gear ratio for subsequent actuation), the system provides optimized force output for different phases of the surgical task rather than using a fixed geometric progression.
Solution Approach 2:
The patent applies segmentation by dividing the actuation stroke into distinct phases with different mechanical advantage requirements. The first actuation portion uses one mechanical advantage ratio, while the second actuation portion uses a different ratio, allowing each phase to be optimized for its specific function (e.g., initial engagement vs. final deployment).
3Ease of operation
If a variable mechanical advantage system is implemented, then force requirement is reduced and surgical tasks are performed more efficiently, but the gear mechanism becomes more complex
Solution Approach 1:
The complex variable mechanical advantage system is segmented into discrete, manageable gear components (first gear, second gear, third gear, fourth gear) that can be independently manufactured and assembled. This segmentation allows the complex functionality to be achieved through modular components rather than a single complex mechanism.
Solution Approach 2:
The patent introduces intermediate gears (second gear and third gear) that mediate between the movable handle and the drive member. These intermediary gears enable the transmission and transformation of mechanical advantage through multiple stages, reducing the force requirement while distributing the complexity across multiple simpler components rather than requiring a single complex mechanism.
Data Source
AI summary
A surgical instrument includes a handle assembly having a gear drive mechanism. The gear drive mechanism includes a variable radius gear to provide a desired mechanical advantage to a user during actuation of a movable handle of the surgical instrument.