Ultrasonic Transducer Slip Lock Torque Limiting

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Solution Overview

Problem

Current ultrasonic surgical instruments face challenges in ensuring proper coupling of the acoustic waveguide with the transducer assembly, leading to potential overtightening or undertightening, which can affect the precision and safety of surgical procedures.

Innovation Solution

The integration of a detent cam slip lock mechanism within the handle assembly that inhibits rotation of the transducer assembly and limits torque to a predetermined level, preventing overtightening and ensuring secure coupling of the waveguide with the transducer assembly, while also providing a torque indicator for the user.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual coupling of the acoustic waveguide with the transducer assembly is performed without a torque limiting mechanism, then the coupling can be secured, but overtightening may occur causing damage or deformation

Engineering Contradiction:
Improvecoupling securityVSAvoidovertightening damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The coupling mechanism includes an integral slip lock that automatically limits torque to a predetermined level during the coupling process. The slip lock is designed to slip or disengage when the torque exceeds the predetermined threshold, thereby preventing overtightening damage without requiring external intervention or complex additional components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The slip lock mechanism is pre-configured with a predetermined torque threshold that acts as a protective barrier before overtightening can occur. This preventive mechanism ensures that the maximum torque applied during coupling will not exceed the safe limit, protecting the waveguide-transducer interface from damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the coupling mechanism is simplified for ease of use, then the operation becomes easier, but precision in achieving proper torque coupling is reduced

Engineering Contradiction:
Improvecoupling operationVSAvoidtorque coupling precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The slip lock mechanism automatically performs the torque limiting function without requiring the operator to precisely control the applied torque. The operator simply needs to apply force to couple the waveguide, and the slip lock will inherently limit the torque to the predetermined level, combining ease of operation with precise torque control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The slip lock acts as an intermediary element between the operator's manual coupling action and the final torque applied to the waveguide-transducer interface. It mediates the torque transmission, ensuring that the precise predetermined torque level is achieved regardless of the operator's applied force magnitude.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If a separate torque wrench is used to couple the waveguide with the transducer assembly, then torque control can be achieved, but the device complexity increases

Engineering Contradiction:
Improvetorque controlVSAvoidcoupling mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The slip lock mechanism is integrated into the existing coupling structure between the waveguide and transducer assembly, merging the torque limiting function with the coupling mechanism itself. This eliminates the need for a separate torque wrench while maintaining precise torque control, thereby reducing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The slip lock serves multiple functions: it acts as both a mechanical coupling element and a torque limiting device. This multi-functionality consolidates what would otherwise require separate components (coupling mechanism plus torque control device), simplifying the overall system while maintaining precision torque control.

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

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

This solution ensures secure and precise coupling of the waveguide with the transducer assembly, preventing damage and ensuring consistent ultrasonic vibrations for effective tissue cutting and coagulation, while providing a user-friendly torque indication.

Implementation Method 1

These instruments include piezoelectric elements that convert electrical power into ultrasonic vibrations, which are communicated along an acoustic waveguide to the blade element.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The integration of a detent cam slip lock mechanism within the handle assembly that inhibits rotation of the transducer assembly and limits torque to a predetermined level

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3554394B1Ultrasonic surgical instrument with integral slip lock between the instrument body and the ultrasonic transducer
Publication Date: 2020.07.01 ETHICON INC
  • EP3554394B1 patent drawingFigure 1
  • EP3554394B1 patent drawingFigure 2
  • EP3554394B1 patent drawingFigure 3A~4

AI summary

A surgical instrument includes an instrument body, an ultrasonic transducer assembly, and a slip lock having an arrester. The transducer assembly is rotatably mounted along a longitudinal axis within the body such that the transducer assembly is configured to selectively rotate. The arrester is configured to move relative to the ultrasonic transducer assembly between an engaged position and a disengaged position and has a catch portion and a deflectable portion. The catch portion is configured to seize the transducer assembly and selectively inhibit rotation for rotatably coupling with the acoustic waveguide up to a predetermined torque. The deflectable portion is configured to deflect relative to the transducer assembly upon receiving a torque greater than the predetermined torque. Accordingly, the catch portion releases the transducer assembly to slip relative to the catch portion for limiting coupling of the transducer assembly with the acoustic waveguide to the predetermined torque.