Rotatable Actuator for Complete Injection Needle Retraction

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Solution Overview

Problem

Existing medical instruments with radially outwardly directed injection needles face issues with incomplete retraction, leading to potential tissue damage during withdrawal, especially in thin needles, and require axial displacement that can cause bending or sticking.

Innovation Solution

A medical instrument with a rotatable actuator mechanism that moves needles between retracted and extended positions via rotation, using teeth engagement to ensure safe and efficient deployment and retraction without axial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the injection needle tip is held firmly in the puncture position by tissue, then the needle remains deployed for medicament administration, but the needle cannot be fully retracted into the tubular body, causing potential tissue damage during withdrawal

Engineering Contradiction:
Improveneedle deployment reliabilityVSAvoidtissue damage during withdrawal
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional elastic mechanical return system with a controlled actuation system. Instead of relying on elastic forces that cannot ensure complete retraction, the invention uses an actuator (such as a balloon or mechanical pusher) that can be controlled to actively push the needle tip back into the tubular body, ensuring complete retraction and eliminating tissue damage risk during withdrawal

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The actuator system is designed to automatically control the needle tip retraction without requiring additional manual intervention. The same control mechanism that deploys the needle can also retract it, making the system self-sufficient for both deployment and retraction operations

Inventive Principle:
Principle #25Self-service

2Ease of operation

If axial displacement is used to deploy and retract injection needles, then needles can be moved in and out, but thin needles become caught, stuck, or damaged due to shearing forces

Engineering Contradiction:
Improveneedle deployment operationVSAvoidneedle structural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent changes the deployment direction from axial (parallel to the tubular body axis) to radial (perpendicular to the axis). The needle tip is pushed radially outward through the tubular wall rather than being axially displaced, which eliminates shearing forces and prevents bending or sticking of thin needles during deployment and retraction

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Ensures complete retraction of injection needles into the tubular body, preventing tissue injury during withdrawal and eliminating the risk of shearing forces on thin needles.

Implementation Method 1

If the balloon is inflated, whether by means of a liquid or a pressurized gas, the inflated balloon presses the tip portion radially outwards

Methodology Applied
Scientific EffectPressurisation: Pressurisation

Implementation Method 2

The return of the outwardly directed tip portion then takes place on the basis of the elasticity of the outwardly directed tip portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3941372B1Medical instrument with injection needles
Publication Date: 2025.09.17 DOC INVENT SA
  • EP3941372B1 patent drawingFigure 1~3
  • EP3941372B1 patent drawingFigure 4~6
  • EP3941372B1 patent drawingFigure 7~10

AI summary

The invention concerns an instrument, for a medical application, said instrument comprising a body (1), at least one needle, channel means (15) to bring a fluid to said at least one needle, and actuating means (6) for moving said at least one needle from a retracted position to an extended position by rotation of actuating means (6) with respect to the body.