Rotatable Shaft Locking Positions for Surgical Instruments

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Solution Overview

Problem

Current surgical instruments, such as ultrasonic and electrosurgical devices, face challenges in preventing inadvertent rotation of shaft assemblies during surgical procedures, which can lead to misalignment and require repositioning of the end effector, potentially causing inefficiencies and complications.

Innovation Solution

The implementation of rotation locking mechanisms, including spring clamps, trigger-driven clutching locks, and cam-driven locking systems, which selectively lock and unlock the shaft assembly relative to the handle assembly, ensuring precise control and orientation of the end effector by preventing unintended rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the shaft assembly is made rotatable to improve maneuverability during surgical procedures, then the ease of operation is improved, but the risk of inadvertent rotation and misalignment increases

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidalignment stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The shaft assembly incorporates a rotatable section that can dynamically transition between locked and unlocked states. The locking mechanism includes a locking member with engagement features that can be selectively engaged or disengaged, allowing the shaft to be fixed in desired orientations during surgery while permitting intentional repositioning when needed. This dynamic control resolves the contradiction by providing both maneuverability and alignment stability at different operational phases.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If multiple locking positions are provided to improve positioning precision, then the manufacturing precision and control accuracy are improved, but the device complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidlocking mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The locking mechanism is segmented into discrete locking positions with corresponding engagement features distributed around the circumference of the shaft assembly. The locking member includes multiple engagement features that can selectively engage with corresponding features on the shaft at different angular positions. This segmentation provides precise positioning at multiple discrete orientations while keeping the mechanism relatively simple through modular, repeatable engagement features rather than continuous adjustment mechanisms.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3282973B1Surgical instrument with rotatable shaft having plurality of locking positions
Publication Date: 2022.10.19 ETHICON INC
  • EP3282973B1 patent drawingFigure 1
  • EP3282973B1 patent drawingFigure 2
  • EP3282973B1 patent drawingFigure 3

AI summary

An apparatus comprises a body assembly, a shaft, an end effector, a rotation input feature, and a locking feature. The shaft extends distally from the body assembly and defines a longitudinal axis. The end effector is positioned at the distal end of the shaft. The rotation input feature comprises a proximal end and a distal end. The rotation input feature is configured to rotate one or both of the shaft assembly or the end effector about the longitudinal axis. The locking feature is configured to transition between a locked state and an unlocked state. The locking feature is configured to prevent rotation of the one or both of the shaft assembly when the locking feature is in the locked state. The locking feature is configured to permit rotation of the one or both of the shaft assembly when the locking feature is in the unlocked state.