Drug Delivery Holder Safety Shield Deployment Mechanism
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Solution Overview
Problem
Existing needle shielding devices for drug delivery devices, such as hypodermic syringes, often require complex manipulation, lack precise control, and can unintentionally deploy, interfering with medication dispensing or rendering the device unusable during shipment or use.
Innovation Solution
A holder with a selectively deployable safety shield that is spring-loaded and moves from a retracted to an extended position to cover the needle tip after use, activated by aligning and mechanically coupling components on the holder and syringe, allowing for either passive or active deployment without additional user action at the end of the injection stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deployable safety shield is added to the syringe assembly, then user safety is improved by preventing accidental needle-stick injuries, but device complexity increases due to additional components and deployment mechanisms
Solution Approach 1:
The safety shield is nested within the holder structure, with the shield positioned inside the holder's cylindrical wall. The shield and holder form a compact integrated assembly where the shield can move longitudinally within the holder's confines, reducing overall device complexity while maintaining safety functionality
Solution Approach 2:
The biasing means (spring) automatically returns the shield to its retracted position after deployment, and the alignment of components during the injection stroke automatically triggers shield deployment. This self-service mechanism eliminates the need for additional actuators or complex control systems, improving reliability while managing device complexity
2Ease of operation
If the safety shield is made to deploy automatically upon completion of injection stroke, then ease of operation is improved by requiring no additional user action, but reliability may worsen due to risk of unintended deployment during shipment or before use
Solution Approach 1:
The release mechanism uses localized alignment features (protrusions and recesses) that are only in the correct positional relationship when the syringe is fully inserted into the holder. This local quality ensures the shield only deploys when the syringe is properly positioned, preventing unintended deployment during shipment while maintaining ease of operation
Solution Approach 2:
The components are pre-configured in specific positions within the holder and syringe assembly. The protrusion and recess are preliminarily positioned such that they can only align when the syringe is fully inserted, ensuring the shield deployment is triggered at the correct moment without requiring additional user action
3Measurement precision
If the safety shield deployment is triggered by alignment of components during injection stroke, then precision control is improved to prevent unintended deployment, but device complexity increases due to multiple components requiring alignment
Solution Approach 1:
The release mechanism is segmented into distinct components: a protrusion on one element and a recess on another. This segmentation allows each component to be independently manufactured and positioned, providing precise control over when the shield deploys while keeping individual components simple
Solution Approach 2:
The alignment between the protrusion and recess acts as an intermediary mechanism that translates the injection stroke into shield deployment. This intermediary provides precise control by ensuring the shield only deploys when the syringe is fully inserted, without requiring complex sensing or control systems
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
Ensures safe containment of the needle tip post-use, preventing accidental needle-stick injuries and ensuring the device remains functional for injection, with enhanced user safety and reliability.
Implementation Method 1
The safety shield is spring-loaded and movable from a first or retracted position in which the forward tip of the needle is exposed, to a second or extended position in which the forward tip of the needle is contained within the safety shield.
Data Source
AI summary
A holder with a safety shield for a drug delivery device; the shield obstructing access to a needle of the drug delivery device following use thereof. The safety shield may be actively deployed, in which case the health care worker must perform an action beyond complete depression of the pusher into the body of the drug delivery device to deploy the shield. Alternatively, the safety shield may be deployed passively or automatically, in which case deployment of the shield occurs upon complete depression of the pusher into the body, with no additional action required of the health care worker. The safety shield is spring-loaded and released to its extended position by a mechanical coupling of a series of position members, including levers, formed on the holder and the drug delivery device.