Surgical Tool Coupling With Multi-Position Torque Locking

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Solution Overview

Problem

Existing surgical tool-pieces face challenges in securing mechanisms that allow for both longitudinal and rotational adjustment while maintaining effective torque transmission, with non-adjustable mechanisms being cumbersome and adjustable mechanisms lacking sufficient torque.

Innovation Solution

A coupling mechanism with at least three radially spaced coupling elements that secure the tool-piece both longitudinally and rotationally, utilizing balls within channels and an O-ring to facilitate easy insertion and a locking ring for secure locking, allowing for multiple selectable longitudinal positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a non-adjustable locking mechanism with a single rotational groove and drive dog is used, then strong driving force and torque transmission are achieved, but the tool-piece cannot be adjusted longitudinally and requires separate features for locking and driving

Engineering Contradiction:
Improvedriving forceVSAvoidlongitudinal adjustability
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The coupling elements are configured to perform both locking and driving functions simultaneously. Each coupling element has a locking surface that engages with a driving surface, merging the previously separate locking groove and drive dog into a single integrated feature that provides both longitudinal securing and torque transmission.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coupling mechanism is designed so that the same coupling elements serve multiple functions: they lock the tool-piece longitudinally at adjustable positions and simultaneously transmit torque for driving. This multi-functional design eliminates the need for separate locking and driving features.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an adjustable locking mechanism with multiple longitudinal locations is used, then longitudinal adjustability is achieved, but torque transmission is insufficient

Engineering Contradiction:
Improvelongitudinal adjustabilityVSAvoidtorque transmission
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The coupling elements are designed with specific local features: locking surfaces oriented at predetermined angles to the longitudinal axis, and corresponding driving surfaces with friction-enhancing characteristics. This local differentiation allows the same component to provide both adjustable positioning and strong torque transmission.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The coupling elements incorporate curved or rounded surfaces that increase contact area and friction between the locking and driving surfaces. This curvature enhances the frictional force available for torque transmission while maintaining the adjustable longitudinal positioning capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If a drive dog with fewer flat surfaces is used, then simpler structure is achieved, but rotational alignment becomes difficult

Engineering Contradiction:
Improvestructure complexityVSAvoidrotational alignment
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The coupling elements feature asymmetric locking surfaces oriented at specific predetermined angles to the longitudinal axis. This asymmetric configuration provides distinct alignment references that guide rotational positioning, making alignment easier even with a simple structure.

Inventive Principle:
Principle #4Asymmetry

4Reliability

If separate features for locking and driving are used, then secure locking is achieved, but the coupling mechanism becomes more complicated

Engineering Contradiction:
Improvelocking securityVSAvoidcoupling mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The coupling mechanism merges the locking groove and drive dog into a single integrated coupling element structure. The locking surface and driving surface are part of the same component, eliminating the need for separate features while maintaining secure locking and reliable torque transmission.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3609412B1Coupling mechanism for a surgical device
Publication Date: 2026.04.08 ZETHON
  • EP3609412B1 patent drawingFigure 1
  • EP3609412B1 patent drawingFigure 2
  • EP3609412B1 patent drawingFigure 3A~3B

AI summary

A surgical tool-piece and a coupling mechanism for a surgical tool-piece are provided. The surgical tool-piece is configured to be driving by a driving mechanism. The surgical tool-piece comprises a shaft having a longitudinal axis running from a distal end of the shaft to a coupling portion at a proximal end of the shaft. The coupling portion comprises a driving section comprising at least three indentations located around the circumference of the coupling portion, each indentation being configured to receive a corresponding driving element of the driving mechanism to secure the tool- piece both longitudinally and rotationally.