Lobed CV Joint Adapter Assembly for Curved Surgical Drives
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Solution Overview
Problem
Traditional CV joints in adapter assemblies of powered surgical devices are complex and costly, making them prohibitive for widespread use.
Innovation Solution
A drive assembly featuring lobed and castellated constant velocity (CV) joints with semi-cylindrical and waist portions to accommodate pivoting, allowing for efficient power transfer through curved portions of the adapter assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional CV joints with ball members and U-shaped sockets are used, then power transfer through curved portions is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The CV joint is segmented into discrete components: a shaft with lobed portions, a yoke with castellated portions, and recesses. This segmentation allows each component to be manufactured separately using standard machining operations, reducing overall complexity while maintaining functional integrity for power transfer through curved adapter portions.
Solution Approach 2:
The invention uses simplified geometric forms (lobed and castellated structures) that replicate the functional behavior of traditional ball-and-socket CV joints without requiring complex spherical surfaces or pinned connections. The lobed-castellated geometry copies the essential motion transmission capability at lower manufacturing cost and structural complexity.
2Reliability
If traditional CV joints with ball members and U-shaped sockets are used, then power transfer through curved portions is achieved, but manufacturing cost increases
Solution Approach 1:
By dividing the CV joint into separable shaft and yoke components with standardized lobed and castellated features, the design enables independent manufacturing and assembly, reducing tooling costs and facilitating volume production while ensuring reliable power transfer through curved adapter portions.
Solution Approach 2:
The invention changes the geometric parameters of the joint from traditional spherical ball-and-socket geometry to lobed-castellated geometry with specific ratios (e.g., three lobes, three castellated portions). These parameter changes enable manufacturing using conventional machining processes, significantly reducing cost while maintaining the necessary power transmission function.
3Adaptability or versatility
If a curved portion is added to the adapter assembly, then end effector positioning flexibility is improved, but drive assembly complexity increases
Solution Approach 1:
The curved adapter portion with integrated CV joints enables dynamic positioning of the end effector while maintaining a relatively simple drive assembly structure. The lobed-castellated CV joints accommodate the curvature and angular variations needed for flexible positioning without requiring complex articulated mechanisms throughout the entire drive train.
Solution Approach 2:
The curved adapter portion acts as an intermediary element between the linear drive shaft and the end effector, providing the necessary angular and positional flexibility. The simplified CV joints within this intermediary component enable adaptive positioning without propagating complexity throughout the entire drive assembly.
Data Source
AI summary
A drive assembly for an adapter assembly of a surgical device includes an input shaft, a middle shaft, and an output shaft. The input shaft includes a proximal portion configured for operable engagement with a drive member of a handle assembly and a distal portion including a first castellated portion. The middle shaft includes a proximal portion having a first lobed portion in operable engagement with the first castellated portion of the input shaft, and a distal portion having a second lobed portion. The output shaft includes a proximal portion having a second castellated portion in operable engagement with the second lobed portion.