Needle Guard with Elastic Spring for Syringe Shielding

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Solution Overview

Problem

Conventional passive anti-needle stick safety devices for prefilled syringes rely on syringe and stopper tolerances, which can interfere with injection mechanics, obscure syringe contents, and hinder inspection processes, and are not independent of geometrical tolerances.

Innovation Solution

A contact trigger release needle guard with a lock collar and device shield, biased by an elastic spring, that attaches to the syringe neck and automatically activates to shield the needle without depending on syringe tolerances, allowing for independent assembly and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional passive anti-needle stick safety devices are mounted to the syringe barrel, then needle protection is achieved, but the devices obscure syringe contents and interfere with inspection processes

Engineering Contradiction:

Improveneedle protectionVSAvoidsyringe content visibility

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The safety device is divided into separate functional components: a needle guard that attaches to the syringe hub and a shield that covers the needle. This segmentation allows the shield to be positioned away from the syringe barrel, maintaining visibility of syringe contents while still providing needle protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety device transitions from a two-dimensional overlay on the syringe barrel to a three-dimensional structure that extends radially outward from the syringe hub. The shield projects laterally to cover the needle without obscuring the syringe barrel, moving the protective function to a different spatial dimension.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional safety devices are applied post-filling, then needle protection is provided, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:

Improveneedle protectionVSAvoidassembly process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The needle guard is pre-assembled onto the syringe hub during syringe manufacturing, before the syringe is filled with medication. This preliminary action integrates the safety device into the syringe assembly process, eliminating the need for separate post-filling attachment steps and reducing overall assembly complexity.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If conventional safety devices depend on syringe and stopper tolerances, then the devices can be simple in structure, but the triggering mechanism is unreliable due to tolerance variations

Engineering Contradiction:

Improvesafety device structureVSAvoidtriggering mechanism

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The needle guard incorporates a self-triggering mechanism that uses the natural insertion motion of the needle into the syringe hub to activate the shield. The shield is biased by a spring and automatically engages when the needle reaches a predetermined position, eliminating the need for complex external triggering mechanisms that depend on precise syringe and stopper tolerances.

Inventive Principle:

Principle #25Self-service

4Ease of operation

If the safety device is positioned under the syringe finger flange, then mounting is simplified, but the operability becomes dependent on syringe and stopper tolerances

Engineering Contradiction:

Improvemounting processVSAvoidoperability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The needle guard is designed with a universal mounting interface that attaches to the syringe hub rather than requiring specific positioning under the finger flange. This universal design allows the device to be mounted on various syringe types without being constrained by specific tolerance requirements of individual syringe components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables safe needle protection without interfering with syringe handling or inspection processes, ensuring the safety device triggers independently of syringe geometry, maintaining operational efficiency and visibility during filling and packaging.

Implementation Method 1

an elastic spring coupled between the device shield and the lock collar

Methodology Applied

Scientific EffectElastic spring: Spring

Data Source

PatentUS11065395B2Contact trigger release needle guard with elastic spring

Publication Date: 2021.07.20 SAFETY SYRINGES INC

AI summary

A needle guard device mountable to a pre-filled syringe in its ready-to-fill state. The device includes a device shield interconnected to a lock collar with flexible member and biased to move relative to the lock collar. The lock collar interfaces with the syringe neck to attach the device to the syringe. As the device shield moves proximally, rotation arms of the lock collar interact with angled cutouts in the device shield, causing the device shield to rotate relative to the lock collar and disengaging one or more keys on the device shield from one or more keyways in the lock collar triggering the device shield to move from a first configuration in which the device shield is retractable to expose a syringe sharp to a second configuration in which the device shield is fixedly positioned to cover the syringe sharp.