Dual-Material Needle Shield Assembly for Low-Force Syringe Removal
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Solution Overview
Problem
Existing syringe needle shields are difficult to remove due to high frictional resistance, requiring excessive force, which can be beyond the capability of some users, and may deform, increasing the required force further.
Innovation Solution
A needle shield assembly with a first needle shield made of a flexible material and a second needle shield made of a harder material, coupled via an annular shoulder or overmolded, distributing the removal force to reduce deformation and friction, allowing for easier removal with forces less than or equal to approximately 5-10 N.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the needle shield is frictionally coupled to the syringe to maintain sterility and protect the needle, then the needle shield can be securely attached, but the force required to remove the needle shield becomes excessive and may deform the shield
Solution Approach 1:
The needle shield is divided into two distinct shields: a first needle shield made of a softer material (e.g., polyethylene) and a second needle shield made of a harder material (e.g., polypropylene). The second needle shield is mechanically coupled to the proximal end of the first needle shield, creating a segmented structure that distributes removal forces and prevents deformation while maintaining secure attachment during use.
2Ease of manufacture
If the needle shield is made of a single material to simplify manufacturing, then production is easier, but the shield may deform during removal increasing the required force
Solution Approach 1:
The needle shield assembly uses composite materials by combining a first needle shield made of a softer material (e.g., polyethylene) with a second needle shield made of a harder material (e.g., polypropylene). This composite structure provides both ease of manufacture through overmolding processes and resistance to deformation during removal, as the harder second shield prevents bending while the softer first shield maintains secure frictional coupling to the syringe.
Data Source
AI summary
A needle shield assembly includes a first needle shield at least partially made of a first material and having a proximal end and a distal end, the proximal end of the first needle shield including a cavity; and a second needle shield at least partially made of a second material, the second needle shield mechanically coupled with at least the proximal end of the first needle shield. Additionally, the second material of the second needle shield is harder than the first material of the first needle shield.