Robotic Surgical Tool Coupling for Precise Applicator Locking

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Solution Overview

Problem

Existing surgical robotic manipulators lack efficient and reliable systems for securely attaching and operating energy applicators, such as drills or saw blades, which are crucial for precise surgical procedures like knee or hip replacements, while also ensuring consistent calibration and tool center point location for navigation systems.

Innovation Solution

A surgical tool assembly with a support structure, axial connector assembly, and drive system that securely locks the energy applicator, allowing it to be rotated and axially retained, while maintaining consistent contact for precise surgical operations and enabling easy replacement of components like protective sheaths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a surgical robotic manipulator uses a secure locking mechanism for energy applicators, then reliability of attachment is improved, but device complexity increases

Engineering Contradiction:
Improveattachment reliabilityVSAvoidconnector assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connector assembly is divided into distinct functional modules: the axial connector assembly with locking mechanism, the collet assembly with compression members, and the drive system with drive shaft. This segmentation allows each component to perform its specific function efficiently while maintaining overall system reliability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The collet assembly is nested within the axial connector assembly, with the compression members positioned inside the collet body. The drive shaft passes through the center of the collet assembly. This nested configuration consolidates multiple functions into a compact structure, improving attachment reliability while minimizing the increase in device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If the energy applicator is securely locked in position, then operational stability is improved, but ease of replacement deteriorates

Engineering Contradiction:
Improveapplicator position stabilityVSAvoidtool replacement ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The locking mechanism transitions from a locked state to an unlocked state through actuation of the release member. The compression members are biased by a spring to maintain continuous contact with the applicator, providing stable positioning during operation. When the release member is actuated, the biasing force releases the locking engagement, allowing easy removal and replacement of the applicator while maintaining stability during use.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the drive system continuously drives the shaft, then productivity is improved, but energy consumption increases

Engineering Contradiction:
Improvesurgical operation efficiencyVSAvoiddrive system energy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The drive system is designed to continuously drive the shaft of the energy applicator during surgical operations, maintaining constant rotational motion for efficient tissue cutting or drilling. The mechanical coupling through the drive shaft and the engagement of the collet assembly ensure continuous power transmission from the motor to the applicator, maximizing surgical productivity.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3528720B1Systems and tools for use with surgical robotic manipulators
Publication Date: 2025.08.06 MAKO SURGICAL CORP
  • EP3528720B1 patent drawingFigure 1
  • EP3528720B1 patent drawingFigure 2
  • EP3528720B1 patent drawingFigure 3

AI summary

A tool for use with a surgical robotic manipulator that comprises an energy applicator including a shaft extending along an axis between a proximal end and a distal end. The shaft has an axial-force receiving surface. A tool assembly comprises a support structure to support the energy applicator, an axial connector assembly arranged to engage and releasably lock the energy applicator to the support structure in a locked state, a drive system coupled to the support structure to rotatably drive the shaft of the energy applicator about the axis, a collet assembly cooperating with the axial connector assembly and configured to apply a force to the axial-force receiving surface of the energy applicator in the locked state, and a reference surface. The force includes an axial component directing the energy applicator proximally into continuous contact with the reference surface in the locked state.