Safety Pen Needle Assembly Dual Shielding Mechanism
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Solution Overview
Problem
Existing pen injectors do not effectively shield the non-patient end of the pen needle after use, leaving it exposed and potentially hazardous.
Innovation Solution
A safety pen needle assembly with a hub, needle, first shield, and second shield, where a biasing element urges the second shield to cover the proximal end of the needle, and a releasable retaining assembly allows passive activation of the second shield by the first shield, ensuring both patient and non-patient ends are shielded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shield is added to cover the proximal end of the needle, then safety is improved by preventing accidental needle sticks, but device complexity increases due to additional components
Solution Approach 1:
The second shield is nested within the first shield structure, with the biasing element and retaining assembly integrated into the existing shield components. This nesting approach allows the proximal end shielding function to be added without requiring a completely separate mechanical system, thereby improving safety while minimizing the increase in device complexity.
Solution Approach 2:
The biasing element automatically urges the second shield to cover the proximal end of the needle after use, and the retaining assembly passively activates this shielding action through the predetermined movement of the first shield. This self-service mechanism eliminates the need for manual operation or additional power sources, achieving enhanced safety through automated, passive activation that does not significantly complicate the device.
2Ease of operation
If a biasing element is used to automatically position the second shield, then ease of operation is improved by eliminating manual shielding, but device complexity increases due to the spring mechanism
Solution Approach 1:
The biasing element provides automatic positioning of the second shield without requiring manual intervention. The shield is self-actuated through the mechanical advantage of the spring mechanism, which stores and releases energy to perform the shielding action. This self-service capability significantly improves ease of operation while the integration of the biasing element into the existing shield structure minimizes the added complexity.
Solution Approach 2:
The biasing element is pre-loaded during assembly to store potential energy that automatically positions the second shield in the correct location during use. This preliminary action ensures that the shield is always in the proper position without requiring manual adjustment or complex control systems, thereby improving ease of operation with minimal increase in device complexity.
3Ease of operation
If a releasable retaining assembly is implemented for passive activation, then ease of operation is improved by enabling automatic shield deployment, but device complexity increases due to the retention mechanism
Solution Approach 1:
The retaining assembly is designed to passively activate the second shield through the predetermined movement of the first shield during normal operation. The mechanism automatically senses and responds to the operational state changes, deploying the shield without requiring manual activation or complex control systems. This self-service approach improves ease of operation while keeping the retention mechanism relatively simple through its integration with existing components.
Solution Approach 2:
The retaining assembly acts as an intermediary mechanism that translates the predetermined movement of the first shield into the activation of the second shield. This intermediary function allows for automatic shield deployment by mediating between the user's action of moving the first shield and the resulting activation of the proximal end shield, thereby improving ease of operation with a relatively simple retention mechanism that leverages existing structural movements.
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 solution provides comprehensive shielding of both ends of the pen needle, enhancing safety by preventing accidental needle sticks and ensuring the non-patient end is protected after use.
Implementation Method 1
a second shield (18) which has a biasing element disposed to urge the second shield proximally towards a proximal end of the needle
Data Source
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AI summary
A safety pen needle assembly is provided herein which includes a hub and a needle fixed to the hub. Further, a first shield is provided, along with a second shield which has a biasing element disposed to urge the second shield proximally towards a proximal end of the needle. The assembly further includes a releasable retaining assembly for releasably retaining the second shield in an initial position against the force of the biasing element. A predetermined extent of movement of the first shield causes the retaining assembly to release the second shield. With the second shield being released, the second shield is urged proximally by the biasing element to a second position where the second shield covers the proximal end of the needle. Advantageously, an assembly is provided which allows for passive activation of a shield on a non-patient end of a pen needle assembly by a patient-end shield.