Ball-In-Socket Screw Driver for Stable Angled Torque Transmission
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Solution Overview
Problem
Existing driver devices for spinal screws in procedures like ALIF and XLIF face challenges with u-joints providing inadequate angulation control and bushing wear, leading to difficulty in maintaining force and stability during screw insertion.
Innovation Solution
A ball-in-socket joint mechanism with a spherical head, retention cap, and housing that allows for stable angulation and torque transmission, featuring grooves and pins for precise articulation and a bushing system for secure screw engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a u-joint is provided to allow articulation, then the driver head can articulate with respect to the input shaft, but the range of angulation makes it difficult to maintain appropriate force on the component being driven
Solution Approach 1:
The articulation mechanism is divided into discrete segments: a spherical head at the driver tip, a retention cap with a domed surface, and a housing with a tapered end. These segmented components work together to provide articulation while maintaining force, resolving the contradiction between adaptability and ease of operation
Solution Approach 2:
The spherical head with grooves and the domed surface of the retention cap create a ball-in-socket joint that enables controlled articulation. The curved surfaces allow the driver head to articulate while maintaining stable contact points, enabling both adaptability and force maintenance
2Ease of operation
If a bushing is used to retain the driver tip, then the driver tip can be held in position, but the bushing wears out over time causing the driver tip to move around
Solution Approach 1:
The spherical head replaces the traditional bushing retention mechanism. The grooves in the spherical head work with pins or protrusions in the housing to retain the driver tip without relying on a wearing bushing, thus maintaining both ease of operation and reliability
Solution Approach 2:
The wear-prone bushing mechanism is replaced with a pin-and-groove mechanical system. The pins pass through the housing and are received within the grooves of the spherical head, creating a wear-resistant retention mechanism that maintains driver tip stability
3Power
If pins are added to pass through the housing and engage grooves in the spherical head, then torque transmission is improved, but the device complexity increases
Solution Approach 1:
The spherical head serves multiple functions: it provides articulation through its spherical geometry, transmits torque through the grooves and pins, and maintains position through the interaction with the retention cap and housing. This multi-functionality improves torque transmission without proportionally increasing complexity
Solution Approach 2:
The grooves defined in the spherical head create efficient torque transmission paths while maintaining a compact structure. The curved geometry of the spherical head allows for natural load distribution, improving power transmission without requiring additional complex components
Data Source
AI summary
An articulating driver having a ball-in-socket joint. The driver may include a driver tip having a spherical head, a retention cap having a domed surface to mate with the spherical head, an input shaft, a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface, and a housing that receives the input shaft, the spring, the retention cap and the spherical head. The housing may have a tapered end to positionally retain the spherical head therein. In another aspect, the driver may include a driver tip coupled to the input shaft that includes an interface to engage a screw. A bushing may engage the driver tip at one end and receive the screw at the other end to retain the screw within the driver.