Cannulated Torque-Limiting Driver With Spring-Loaded Shanks

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Solution Overview

Problem

Disposable torque-limiting drivers in the medical industry face challenges in imparting higher torques for larger applications, as traditional systems require multiple part-to-part transitions and are not reliable for high-torque applications.

Innovation Solution

A torque-limiting driver design featuring a spring-loaded mechanism with a shaft and nut configuration that engages and disengages relative rotation based on a predetermined torque limit, allowing for higher torque transfer with fewer part transitions and incorporating a lumen for potential biologic material delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional piecemeal drivetrain systems are used in disposable torque-limiting drivers, then the device can be disposed of after use, but the multiple part-to-part transitions reduce reliability for high-torque applications

Engineering Contradiction:
ImprovereliabilityVSAvoidnumber of part transitions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple drivetrain components into a single integrated shaft assembly. The shaft includes a drive connection at one end and a workpiece-engaging tip at the other, with torque transfer features that eliminate the need for multiple separate drivetrain parts. This merging of components reduces part-to-part transitions and improves reliability for high-torque applications while maintaining the disposable nature of the driver.

Inventive Principle:
Principle #5Merging (Combining)

2Force

If disposable drivers are designed for low torque applications, then they can be discarded after use, but they cannot impart higher torques required for larger applications

Engineering Contradiction:
ImprovetorqueVSAvoidreliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent employs a spring mechanism that can be pre-compressed to different degrees during assembly, allowing the torque-limiting driver to be configured for different torque levels. By changing the compression parameter of the spring and adjusting the engagement force between torque transfer features, the same basic disposable driver design can reliably impart higher torques for larger applications while maintaining disposability.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables reliable high-torque applications with reduced part transitions, maintaining precision and accuracy, and can deliver biologic materials like adhesives or growth stimulants, enhancing surgical precision and efficiency.

Implementation Method 1

a spring between the upper cylindrical shank and the nut, wherein the spring is configured to apply a force across the upper cylindrical shank and the lower cylindrical shank

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2566412B1Cannulated ultra high torque device
Publication Date: 2020.05.06 ECA MEDICAL INSTR
  • EP2566412B1 patent drawingFigure 1
  • EP2566412B1 patent drawingFigure 2A
  • EP2566412B1 patent drawingFigure 2B

AI summary

A torque-limiting device may include a shaft extending axially through upper and lower shanks and a spring to connect to a nut. The upper and lower shanks may be under a force from the spring and further configured to selectively engage within a predetermined torque limit and disengage at above the predetermined torque limit. Accordingly, the shaft may receive torque up to the predetermined limit as provided by a user operating a handle of the torque-limiting device. The torque-limiting device may be disposable, reusable, economical, and have high torque capabilities. The shaft may include a lumen extending there through, and through which a variety of devices and materials may be delivered to a workpiece.