Instrument Coupling Interface for Repeatable Six-DOF Alignment

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Solution Overview

Problem

Existing surgical navigation systems face precision issues due to overdetermined geometries in instrument coupling interfaces, leading to inconsistent and repeatable attachment of navigation arrays to instruments, which can result in navigational inaccuracies and increased costs.

Innovation Solution

A coupling assembly with a cylindrical surface and a prismatic surface, secured by a screw and pin configuration, restricting movement in all six degrees of freedom, minimizing play and ensuring repeatable orientation between the navigation array and the surgical instrument.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If overdetermined geometries with multiple contacting surfaces are used to connect the navigation array to the instrument, then the connection appears more secure, but manufacturing tolerances and mechanical deformation compound the risk, leading to inconsistent and non-repeatable attachment precision

Engineering Contradiction:

Improveconnection securityVSAvoidattachment repeatability

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent extracts the essential constraint functions from the overdetermined geometry, retaining only the minimum necessary contacting surfaces (two surfaces) to constrain the navigation array relative to the instrument. This eliminates the compounding effects of multiple contacting surfaces while maintaining connection security and attachment repeatability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using multiple contacting surfaces to over-constrain the connection, the patent inverts the approach by using exactly two contacting surfaces to achieve precise constraint. This minimal surface approach eliminates tolerance accumulation and mechanical deformation issues associated with overdetermined geometries.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If welding or integrally-forming the navigation array to the instrument is done, then high precision navigation is achieved, but the capability to decouple the array from the instrument or to couple the array to other instruments is lost

Engineering Contradiction:

Improvenavigation precisionVSAvoidinterchangeability

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the navigation system into separable components: the navigation array and the instrument, connected through a standardized coupling interface. This allows the navigation array to be decoupled and recoupled to different instruments while maintaining high precision through the controlled two-surface contact geometry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a universal coupling interface that can accommodate different instrument-array combinations. The standardized two-surface contact design enables the navigation array to be interchangeably coupled to various instruments, providing adaptability and versatility while maintaining consistent navigation precision across different configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If standard interchangeable connections with dovetail or v-groove geometries are used, then the navigation array can be decoupled and recoupled to different instruments, but the larger number of contacting surfaces compound manufacturing tolerances, reducing navigation precision

Engineering Contradiction:

ImproveinterchangeabilityVSAvoidnavigation accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent extracts only the essential constraint functions from traditional dovetail or v-groove geometries, reducing the contacting surfaces to exactly two surfaces. This minimal surface approach eliminates the tolerance accumulation problem while maintaining the ability to decouple and recouple the navigation array to different instruments.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of following conventional multi-surface geometries, the patent inverts the approach by using exactly two contacting surfaces to achieve precise constraint. This inversion eliminates the compounding effect of manufacturing tolerances across multiple surfaces while preserving interchangeability through the standardized coupling interface.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12060908B2Instrument coupling interfaces and related methods

Publication Date: 2024.08.13 MEDOS INT SARL

AI summary

A coupling and related methods are disclosed herein that can provide for coupling a first object and a second object with minimal play. A coupling can include a first coupling component having a cylindrical surface with a screw and a pin extending therefrom and a second coupling component having a prismatic surface with a first and a second through-hole. The first coupling component and the second coupling component can be configured such that relative motion between the first coupling component and the second coupling component can be restricted in all six degrees of freedom when the screw is engaged with the first through-hole to secure the cylindrical surface of the first component against the prismatic surface of the second component. The pin can be configured to maintain stability of the coupling and further limit relative movement, such that positioning and/or orientation errors between the first and second components is minimized.