Syringe Needle Shield Frangible Web for Tamper Evidence

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Solution Overview

Problem

Existing syringe needle shields lack consistency in pull-out force, which can lead to mismatch with the break-apart force of tamper-evident features, potentially allowing the shield to be removed without breaking, compromising syringe integrity.

Innovation Solution

A needle shield design featuring a rigid outer casing with a frangible portion secured by a circumferential web, where the pull-out force required for removal equals the force needed to break the web, ensuring consistent and tamper-evident removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the needle shield is designed with a frangible web for tamper evidence, then the syringe integrity can be ensured, but the pull-out force may not match the break-apart force, potentially allowing removal without breaking the web

Engineering Contradiction:

Improvesyringe integrityVSAvoidneedle shield removal consistency

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by carefully designing the frangible web's physical properties (thickness, material composition, geometric configuration) to ensure its break-apart force matches the needle shield's pull-out force. This optimization of physical parameters resolves the contradiction between ensuring syringe integrity through tamper evidence and maintaining consistent, predictable removal operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates dynamics by designing the frangible web to transition from a connected state to a broken state at a specific force threshold. This dynamic behavior ensures that when the needle shield is removed, the frangible web breaks at the exact moment of removal, providing tamper evidence while maintaining consistent operational force requirements.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the pull-out force is reduced for easier removal, then the needle shield can be removed more easily, but the frangible web may not break, compromising tamper evidence functionality

Engineering Contradiction:

Improveneedle shield removabilityVSAvoidtamper evidence effectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent resolves this contradiction by optimizing the frangible web's physical parameters (material properties, thickness, dimensions) to create a force threshold that aligns with the natural removal force of the needle shield. This ensures that easy removal operation automatically triggers frangible web breaking, maintaining both ease of operation and tamper evidence reliability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the frangible web is made stronger to ensure tamper evidence, then the break-apart force increases, but the needle shield requires excessive pull-out force for removal

Engineering Contradiction:

Improvetamper evidence reliabilityVSAvoidpull-out force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent addresses this contradiction by precisely controlling the frangible web's physical parameters to set an optimal break-apart force threshold. This optimized design ensures the web is strong enough to provide reliable tamper evidence but not so strong as to require excessive removal force, balancing reliability with acceptable operational force requirements.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If the needle shield construction is modified to change pull-out force, then removal consistency can be improved, but the match with frangible web break-apart force may be lost

Engineering Contradiction:

Improvepull-out force consistencyVSAvoidforce matching with frangible web

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent merges the needle shield construction with the frangible web design into an integrated system where both components are optimized together. This combined design ensures that the pull-out force consistency of the needle shield naturally aligns with the break-apart force of the frangible web, achieving both removal consistency and force matching simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4527434A1Syringe needle shield with tamper evidence feature and consistent needle pull-out force

Publication Date: 2025.03.26 BECTON DICKINSON & CO

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AI summary

Provided herein is a prefilled or prefillable syringe that includes a syringe assembly and a plunger assembly. The syringe assembly includes a syringe barrel defining a chamber and a tip member at a distal end thereof, a needle having fixedly inserted into the tip member, and a needle shield having a proximal end secured to the tip member of the syringe barrel, so as to be positioned over the needle. The needle shield comprises a rigid outer casing and a compliant inner casing, characterized in that the rigid outer casing includes a tamper evident frangible portion at the shield proximal end, with the frangible portion secured to a main body portion of the rigid outer casing by a circumferential frangible web, and wherein the frangible portion includes a hook system that engages a radial bump formed on the tip member, to engage the needle shield with the syringe barrel.