Needle Shield Internal Roughness for Alignment and Sterility
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Solution Overview
Problem
Existing needle shields for administration devices often fail to align properly during automatic assembly, leading to incorrect positioning, contamination risks, sterility issues, and damage to needles due to their sticky nature and inadequate fit on hubs, causing manufacturing line disruptions and usability problems.
Innovation Solution
A shield with a specific internal surface feature, characterized by a mean radial roughness greater than 2 μm and less than 100 μm, featuring microreliefs such as grooves or ridges that reduce contact area and prevent sticking, ensuring correct alignment and easy removal, while maintaining sterility and preventing needle damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shield is made of elastic material to ensure sterility and protection, then the shield provides good sealing and protection, but the shield becomes sticky and difficult to remove
Solution Approach 1:
The internal face of the shield is segmented into multiple zones with different roughness characteristics. The first zone (proximal to the hub) has higher roughness to reduce adhesion, while the second zone (distal to the hub) has lower roughness to maintain sealing. This segmentation allows the shield to simultaneously achieve easy removal and good sealing performance.
Solution Approach 2:
Different regions of the shield's internal face are given different surface qualities. The proximal region near the hub has a rougher surface to minimize contact area and adhesion forces, while the distal region has a smoother surface to ensure proper sealing against the administration device. This local differentiation resolves the contradiction between easy removal and effective sealing.
2Productivity
If automatic assembly is used to improve manufacturing efficiency, then productivity increases, but the shield misalignment and positioning errors occur
Solution Approach 1:
The shield's internal face is designed with a specific roughness profile that enables self-alignment during automatic assembly. The rougher first zone creates a positioning effect that guides the shield into correct orientation on the hub, while the friction characteristics of the elastomeric material work with the surface topology to maintain proper alignment without requiring additional alignment mechanisms.
3Reliability
If the shield is tightly fitted to ensure sterility, then protection is improved, but contamination from elastomeric particles increases
Solution Approach 1:
The internal face is divided into zones with different roughness to balance sterility and contamination prevention. The first zone with higher roughness reduces adhesion and minimizes particle generation, while the second zone with lower roughness provides sealing. This segmentation allows the shield to maintain sterility without excessive contact that would generate contaminating particles.
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 shield facilitates correct and secure fitting on administration devices, reduces contamination risks, and allows for easy removal, enhancing manufacturing efficiency and maintaining sterility by minimizing contact between the needle and shield material.
Implementation Method 1
the shield happens to stuck on the hub of the administration device in an inappropriate position
Data Source
AI summary
The present invention relates to a shield (10) for the distal extremity of an administration device (3) comprising a hub (2) on which said shield (10) is to be removably engaged, said shield (10) having a wall (13) the internal face (14) of which defining an interior cavity (15) for receiving the extremity of the administration device (3), at least a portion (14a) of said internal face (14) being intended to be in contact with said hub (2) when said shield (10) is engaged on the extremity of said administration device (3), whereby said portion (14a) has, distributed over a major portion of said portion (14a), a surface feature (16, 17) that defines the amount of contact between said portion (14a) and said hub (2).