Pin-Drive Surgical Tool Coupling for Self-Aligning Torque Transfer
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Solution Overview
Problem
Current surgical cutting tools and powered handpieces face issues with high contact stresses and reduced interface stiffness due to complex machining requirements, leading to reliability concerns and alignment problems during tool coupling.
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, enhancing torque transfer and reducing alignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If complex machining/grinding is used to achieve torque transmission and axial retention features, then torque transmission capability is improved, but contact stresses increase and interface stiffness decreases
Solution Approach 1:
The coupling interface is segmented into distinct functional zones: the drive chuck with drive pins, the deflection surface for alignment, and the interface structures with driven surfaces. This segmentation allows each component to be optimized independently, reducing complex machining requirements while maintaining torque transmission capability.
Solution Approach 2:
The deflection surface is designed to perform preliminary self-alignment of the interface structure with the drive pin before final engagement. This preliminary action ensures proper orientation and reduces misalignment stresses during operation, improving interface reliability without requiring complex machining.
2Strength
If complex machining/grinding is used to achieve torque transmission and axial retention features, then torque transmission capability is improved, but manufacturing complexity increases
Solution Approach 1:
The coupling interface is segmented into distinct functional zones: the drive chuck with drive pins, the deflection surface for alignment, and the interface structures with driven surfaces. This segmentation allows each component to be optimized independently, reducing complex machining requirements while maintaining torque transmission capability.
Solution Approach 2:
The deflection surface enables self-alignment of the interface structure with the drive pin during insertion. This self-service mechanism eliminates the need for complex precision machining and alignment procedures, significantly reducing manufacturing complexity while ensuring proper engagement.
3Ease of manufacture
If point contacts are created solely about the single central axis, then manufacturing is simplified, but alignment precision decreases
Solution Approach 1:
The deflection surface introduces a new dimensional aspect to the coupling interface by creating an oblique surface that engages with the drive pin at an angle. This additional dimensional element enables self-alignment in both axial and rotational directions, achieving high alignment precision without complicating the basic cylindrical shaft geometry.
4Device complexity
If the shank is shaped as an elongated cylinder with single central axis, then device complexity is reduced, but alignment capability deteriorates
Solution Approach 1:
The deflection surface introduces a new dimensional aspect to the coupling interface by creating an oblique surface that engages with the drive pin at an angle. This additional dimensional element enables self-alignment in both axial and rotational directions, achieving high alignment precision without complicating the basic cylindrical shaft geometry.
Solution Approach 2:
The deflection surface enables self-alignment of the interface structure with the drive pin during insertion. This self-service mechanism automatically corrects misalignment without requiring complex external alignment tools or procedures, maintaining ease of operation while improving alignment capability.
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.