Locking Mechanism for Extendable Shaft with Compression Flanges

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Solution Overview

Problem

Existing combination electrosurgical instruments with extendable shafts for smoke evacuation often require reassembly during surgical procedures, which can cause delays and pose safety risks due to loose locking mechanisms that allow the shaft to be freely removed, leading to potential damage and operational failures.

Innovation Solution

A locking mechanism with a locking nut that securely engages and disengages the extendable shaft, utilizing a sliding conductor for electrical connectivity and a conduit for smoke evacuation, allowing the shaft to be locked in various positions without the need for reassembly, ensuring stability and safety during procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking feature is provided to secure the extendable shaft, then the shaft can be locked in various positions, but when the locking feature is loosened or unlocked, the shaft can be freely removed from the hand piece requiring reassembly

Engineering Contradiction:
Improveshaft retentionVSAvoidshaft removal control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism transitions between locked and unlocked states through rotation of the locking nut, dynamically changing the engagement state of the compression flanges with the shaft. When locked, the flanges are compressed against the shaft to prevent removal; when unlocked, the compression is released allowing controlled removal or repositioning.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism changes the compression force parameter applied by the flanges to the shaft. In the locked state, high compression force secures the shaft; in the unlocked state, the compression force is reduced or eliminated, allowing the shaft to be freely removed or repositioned without requiring full disassembly.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the shaft can be freely removed when unlocked, then reassembly is possible, but this creates delays and safety risks during surgical procedures

Engineering Contradiction:
Improveshaft repositioning capabilityVSAvoidprocedural delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The mechanism allows dynamic transition between secured and repositionable states through simple rotation of the locking nut, enabling quick adjustments without time-consuming disassembly and reassembly procedures.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the locking mechanism is loosened, then the shaft can be repositioned, but attempts to reassemble may result in damage to the device

Engineering Contradiction:
Improveshaft repositioningVSAvoiddevice integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking mechanism provides a controlled dynamic system where the shaft transitions between fixed and movable states through rotation of the locking nut. The compression flanges gradually engage or disengage from the shaft, preventing sudden movements or misalignments that could damage the device during repositioning or reassembly.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The compression flanges provide a cushioning effect by gradually engaging with the shaft during the locking process, preventing impact or sudden forces that could damage the device. The tapered geometry of the flanges allows for progressive engagement that cushions against misalignment or improper assembly forces.

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

Data Source

PatentEP3624716B1Locking mechanism for extendable shaft
Publication Date: 2024.03.06 MEGADYNE MEDICAL PRODUCTS INC
  • EP3624716B1 patent drawingFigure 1
  • EP3624716B1 patent drawingFigure 2~3
  • EP3624716B1 patent drawingFigure 4~5

AI summary

An instrument includes a body having an interior conduit. A shaft extends distally out of the body and is movable between a retracted position and an extended position. A locking mechanism that selectively secures the shaft in the retracted and extended positions includes grooves in the body and a locking nut having pins that travel through the grooves to move the locking nut between a locked position and an unlocked position. The locking mechanism also includes compression flanges that flex towards and apply pressure/friction to the shaft when the locking nut is in the locked position and release/reduce the pressure/friction from the shaft when the locking nut is in the unlocked position. The compression flanges restrict the movement of the shaft when the compression flanges are flexed towards, and apply pressure to the shaft.