Retractable Needle Syringe Design for Single-Use Safety

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Solution Overview

Problem

Existing retractable syringes are complex in design and costly to produce on a large scale, making them inefficient for mass production while ensuring single-use functionality and safety against disease transmission and needle pricks.

Innovation Solution

A simple and cost-effective retractable syringe design featuring a hollow barrel with a plunger and needle assembly, where the needle holder is biased by a resilient member and secured with a retaining member, allowing for easy retraction into a retraction cavity upon plunger depression, ensuring single-use functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing retractable syringe designs are used, then needle retraction and single-use functionality are achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvesingle-use functionalityVSAvoiddesign complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The syringe is divided into distinct functional components: a barrel, a plunger with end wall, a needle assembly with needle holder, and a retaining member. This segmentation allows each component to perform its specific function independently, simplifying the overall design while ensuring reliable single-use functionality through coordinated interaction of these modular parts

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The needle holder is positioned within the plunger structure, and the retaining member is integrated into the needle holder assembly. This nested arrangement reduces the number of separate components and simplifies the overall device structure while maintaining the retraction mechanism's functionality

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If existing retractable syringe designs are used, then needle retraction is achieved, but manufacturing cost increases

Engineering Contradiction:

Improveneedle retractionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The syringe is designed as a disposable single-use device where all components (barrel, plunger, needle assembly) are intended for one-time use only. This approach eliminates the need for complex sterilization and reuse mechanisms, significantly reducing manufacturing costs while ensuring reliable needle retraction for safety

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The resilient member automatically biases the needle holder to the retracted position after plunger depression, eliminating the need for additional actuators or complex control mechanisms. The device performs the retraction function automatically through its own internal mechanical properties

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If needle retraction mechanism is added, then safety against needle pricks is improved, but device complexity increases

Engineering Contradiction:

Improveneedle prick preventionVSAvoidretraction mechanism complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The retaining member is pre-configured to hold the needle holder in the extended position during use, then automatically releases and allows retraction after plunger depression. This preliminary setup ensures that the safety function is built-in from the start without requiring additional complex control systems during operation

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The complex multi-component mechanical retraction systems found in existing designs are replaced with a simplified mechanism using a resilient member and retaining member that work together through basic mechanical principles of elasticity and friction, reducing overall complexity while maintaining safety

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 design allows for efficient and safe single-use syringes that minimize manufacturing costs and prevent needle exposure, enhancing patient and healthcare provider safety while facilitating large-scale production.

Implementation Method 1

a resilient member that biases the needle holder toward the proximal end opening of the barrel

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the retaining member is forced to break away and separate from the needle holder along the reduced material section

Methodology Applied

Scientific EffectFracture: Fracture Mechanics

Data Source

PatentUS8684966B2Safety medical syringe with retractable needle

Publication Date: 2014.04.01 MIDLAND MEDICAL DEVICES HOLDINGS LLC

AI summary

A syringe includes a hollow barrel, a hollow plunger movable within the barrel and a needle assembly secured within and at a distal end of the barrel. The needle assembly includes a needle holder, a resilient member that biases the needle holder toward the proximal end opening of the barrel, and a retaining member releasably secured to the needle holder via a reduced material section. The retaining member maintains the needle holder at the distal end of the barrel against the bias of the resilient member. When the plunger is fully depressed within the barrel, the plunger engages the needle holder such that the retaining member is forced to break away and separate from the needle holder along the reduced material section to facilitate retraction of the needle holder and a needle secured to the needle holder into the retraction cavity disposed within the plunger.