Retractable Syringe with Pneumatic Needle Retraction Control

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Solution Overview

Problem

Existing retractable syringes often experience uncontrolled needle retraction, leading to excessive force and blood splattering due to decompression of springs, which complicates safe disposal and user experience.

Innovation Solution

A retractable syringe design with a controlled needle retraction mechanism, utilizing a biasing means like a spring and a user-operable controlling means to regulate the retraction rate, allowing for safe and controlled disposal of the needle without contacting the fluid contents, thereby minimizing blood splattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a compressed spring is used to provide needle retraction, then the needle retraction force is improved, but the retraction becomes uncontrolled and causes blood splattering

Engineering Contradiction:

Improveneedle retraction forceVSAvoidblood splattering

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a controllable retraction mechanism that dynamically regulates the spring's decompression process. The controller gradually releases the spring's stored energy, transforming the static compressed state into a controlled dynamic retraction process, thereby preventing sudden needle movement and blood splattering while maintaining adequate retraction force.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces a controller as an intermediary component between the compressed spring and the needle assembly. This mediator regulates the energy transfer from the spring to the needle, controlling the retraction speed and force to prevent harmful blood splattering while ensuring complete retraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the needle is permanently retractable into the barrel, then syringe re-use is prevented, but the device complexity increases

Engineering Contradiction:

Improvesyringe re-use preventionVSAvoidretraction mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements an automatic retraction system where the compressed spring self-activates after fluid delivery to retract the needle into the barrel without requiring additional user actions. This self-service mechanism ensures reliable single-use prevention while keeping the interface simple for the user.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent pre-compresses the spring during syringe assembly before use. This preliminary action stores the necessary retraction energy in advance, enabling automatic needle retraction into the barrel after fluid delivery without requiring additional user operations, thus preventing re-use while maintaining simplicity.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If a pre-compressed retraction spring is incorporated, then minimal resistance to plunger depression is provided, but excessive force is applied during needle retraction

Engineering Contradiction:

Improveplunger depression resistanceVSAvoidexcessive retraction force

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates a controller that monitors and regulates the spring decompression process during needle retraction. This feedback mechanism adjusts the energy release rate to maintain gentle operation during plunger depression while preventing excessive force during retraction, thereby resolving the contradiction between ease of operation and harmful effects.

Inventive Principle:

Principle #23Feedback

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

The syringe effectively reduces blood splattering and ensures safe, controlled needle retraction, enhancing user experience and safety by allowing for the separation of clean and contaminated components for waste disposal.

Implementation Method 1

retraction of said retractable needle is facilitated by a biasing means, such as a spring or other compressible and/or de-compressible device. Preferably, said spring is initially compressed so that decompression of said spring facilitates retraction of said retractable needle.

Methodology Applied

Scientific EffectSpring compression and decompression: Spring

Data Source

PatentUS8167837B2Controlled retraction syringe and plunger therefor

Publication Date: 2012.05.01 AMGEN INC

AI summary

A retractable syringe (11) and plunger (20) therefore are provided, whereby the plunger comprises a controlling means (62) which facilitates control of the rate of retraction of the retractable needle. By controlling the rate of needle retraction, the likelihood of blood spattering is reduced, thereby improving the user-friendliness and appeal of the retractable syringe. Typically, the syringe is a prefilled syringe. Following plunger depression, a symmetrical ejector member (92) releases the retractable needle (40) from a retaining member (30) to thereby allow retraction of the retractable needle. Needle retraction is facilitated by a biasing means (70), such as a spring or other compressible and/or de-compressible device. The plunger comprises a plunger housing (21), in which is located the controlling means. The controlling means may be a pneumatic air space (324) inside the plunger housing which automatically acts against the retracting needle to thereby control or regulate the rate of retraction.