Needle Shield Locking Mechanism for Trigger-Free Stick Prevention

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Solution Overview

Problem

Existing safety systems for medical needles require a triggering step before use, slowing down medical procedures and increasing device size, and are not suitable for sterile packaging due to oversizing, posing a risk of needle stick injuries.

Innovation Solution

A safety device with a ring and protective shield that automatically locks over the needle tip after use, preventing access and ensuring the needle is covered in all positions, allowing for direct needle tip exposure during use while maintaining a compact size suitable for sterile packaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional safety device with triggering step is used to expose the needle tip, then the needle can be accessed for injection, but the medical procedure is slowed down and the risk of needle stick injury increases

Engineering Contradiction:

Improveease of needle accessVSAvoidspeed of medical procedure

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The protective shield is pre-positioned in a retracted state that automatically exposes the needle tip when the plunger is pressed, eliminating the need for a separate triggering step. This preliminary positioning of the shield allows immediate needle access upon activation of the injection mechanism, thereby maintaining safety while improving procedural speed

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a safety device is added to prevent needle stick injury, then safety is improved, but the overall device size increases making handling and storage difficult

Engineering Contradiction:

Improvesafety against needle stick injuryVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The protective shield is designed to nest within or alongside the existing syringe structure, utilizing the hollow interior space of the barrel. The shield can be positioned inside the barrel when not in use, or integrated into the plunger assembly, thereby providing safety functionality without significantly increasing the external dimensions of the injection device

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The protective shield is designed as a dynamic component that moves between a retracted position (exposing the needle during injection) and a covering position (protecting the needle after use). This dynamic mechanism allows the safety device to adapt its configuration based on the injection stage, providing protection when needed while minimizing size constraints during the injection process

Inventive Principle:

Principle #15Dynamics

3Reliability

If a safety device is added to prevent needle stick injury, then safety is improved, but the device becomes incompatible with sterile packaging for prefilled syringes

Engineering Contradiction:

Improvesafety against needle stick injuryVSAvoidcompatibility with sterile packaging

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The protective shield is designed to be dynamically positioned during the filling process, allowing it to be retracted or removed temporarily to enable needle penetration through the sterile packaging seal. After filling, the shield returns to its protective position, maintaining both sterility integrity and safety functionality

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If a safety device with triggering step is used, then the needle tip can be exposed, but complete exposure is impeded and direct view and access to the needle tip is prevented

Engineering Contradiction:

Improveaccess to needle tipVSAvoidvisibility of needle tip

Core Design Contradiction:

Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The protective shield is pre-configured with transparent or translucent material in the regions that will cover the needle tip during injection. This preliminary design choice allows the needle to be fully exposed and visible through the transparent shield, eliminating the need for additional triggering steps while maintaining complete visibility and access

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12623029B2Safety device for preventing needle stick injury with a needle of a medical injection device

Publication Date: 2026.05.12 BECTON DICKINSON FRANCE SAS

AI summary

A safety device for preventing needle stick injury comprises a ring configured to be attached to the distal tip of a medical injection device, a first hinge portion, and a protective shield. The protective shield comprises a second hinge portion pivotally coupled to the first hinge portion and is configured to adopt successively a storage position covering the needle tip, a retracted position uncovering the needle tip and a safety position covering the needle tip. In the safety position, the protective shield is locked on the ring by engagement of a locking member with a lug on the ring. The locking member is configured to engage the lug when the protective shield transitions from the retracted position to the safety position, passing from one side of the lug to the other, and remaining engaged with the lug for maintaining the protective shield in the safety position.