Pin-Drive Surgical Tool Interface for Self-Aligning Chuck Coupling
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Solution Overview
Problem
Current rotary surgical cutting tools face issues with torque transmission and alignment due to high contact stresses and reduced interface stiffness, leading to reliability concerns and user frustration during surgical procedures.
Innovation Solution
The surgical cutting tool features an elongated shaft with a coupling portion and interface structures that include deflection surfaces, allowing for self-alignment with the drive chuck's pins, enhancing torque transfer and alignment precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If complex machining/grinding is used to achieve torque transmission and axial retention features, then the torque transmission capability is improved, but contact stresses increase and interface stiffness is reduced
Solution Approach 1:
The drive interface is segmented into discrete drive pins and corresponding recesses in the shank, allowing for simplified machining while maintaining effective torque transmission. The interface structure is divided into distinct functional elements (drive pins, recesses, deflection surfaces) that work together to achieve both torque transmission and reliability.
Solution Approach 2:
The drive interface employs asymmetric geometry with drive pins positioned at specific locations and corresponding asymmetric recesses in the shank. This asymmetric design provides effective torque transmission and axial retention without requiring complex machining, while the deflection surfaces compensate for alignment variations.
2Strength
If complex machining/grinding is used to achieve torque transmission and axial retention features, then the torque transmission capability is improved, but manufacturing complexity increases
Solution Approach 1:
The drive interface is segmented into discrete drive pins and corresponding recesses in the shank, allowing for simplified machining while maintaining effective torque transmission. The interface structure is divided into distinct functional elements (drive pins, recesses, deflection surfaces) that work together to achieve both torque transmission and reliability.
Solution Approach 2:
The design changes the geometric parameters of the drive interface, introducing deflection surfaces with specific angles and configurations that enable self-alignment. This parameter optimization allows for simpler manufacturing processes while maintaining effective torque transmission and reducing contact stresses.
3Measurement precision
If the shank and drive chuck are designed for precise alignment, then alignment accuracy is improved, but the coupling process becomes more difficult
Solution Approach 1:
The deflection surfaces are designed to perform preliminary alignment action during the coupling process. As the shank is inserted into the drive chuck, the deflection surfaces make initial contact and guide the alignment, automatically compensating for minor misalignments before the drive pins engage with the recesses. This preliminary self-alignment action ensures accurate coupling without requiring precise manual alignment by the user.
Solution Approach 2:
The drive interface employs self-aligning deflection surfaces that automatically adjust and align the shank with the drive chuck during insertion. This self-service mechanism eliminates the need for user intervention to achieve precise alignment, making the coupling process easier while maintaining high alignment accuracy.
4Device complexity
If point contacts are used in the drive interface, then the structure is simplified, but contact stresses increase and interface stiffness is reduced
Solution Approach 1:
The drive interface is segmented into discrete drive pins and corresponding recesses in the shank, allowing for simplified machining while maintaining effective torque transmission. The interface structure is divided into distinct functional elements (drive pins, recesses, deflection surfaces) that work together to achieve both torque transmission and reliability.
Solution Approach 2:
The design changes the geometric parameters of the drive interface, introducing deflection surfaces with specific angles and configurations that enable self-alignment. This parameter optimization allows for simpler manufacturing processes while maintaining effective torque transmission and reducing contact stresses.
Data Source
AI summary
A surgical cutting tool includes an elongated shaft and a cutting head. The shaft defines a coupling portion terminating at a proximal end of the shaft, a stem portion, and a distal portion. The stem portion defines a central axis. The coupling portion optionally defines a deflection surface positioned oblique with respect to the central axis and connected with a first driven surface and a second driven surface. Upon insertion into a drive chuck, the deflection surface promotes self-alignment of the cutting tool and the drive chuck.