Retainer for Retractable Needle Assemblies
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Solution Overview
Problem
Existing retractable syringes face challenges in preventing inadvertent proximal movement of needles during injection and ensuring easy replacement or selection of needle size, while also maintaining cost-effectiveness and reliability, particularly in designs with replaceable needle assemblies.
Innovation Solution
A retainer system for retractable syringes that includes a body with distally extending retaining members, such as prongs and lateral projections, to prevent inadvertent needle movement, combined with a plunger and barrel assembly that allows for secure engagement and retraction of the needle, and a vial adapter for fluid transfer that prevents accidental retraction activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retractable needle assembly is designed with a retainer to prevent inadvertent proximal movement during injection, then needle retention reliability is improved, but device complexity increases due to additional retaining members and structural components
Solution Approach 1:
The retainer body is integrally formed with the needle hub, combining two separate components into one unified structure. This integration maintains the retaining function while reducing the number of discrete parts, assembly steps, and potential failure points, thereby improving reliability without proportionally increasing device complexity
Solution Approach 2:
The retainer structure serves multiple functions: it provides retaining members to prevent inadvertent proximal movement, offers a mounting interface for attaching the needle assembly to the syringe barrel, and structures the hub to receive the retractable needle. This multi-functionality reduces the need for separate components, addressing the reliability-complexity contradiction
2Reliability
If a highly specialized retractable needle assembly is designed to prevent inadvertent retraction, then safety reliability is improved, but adaptability decreases making needle replacement and size selection difficult
Solution Approach 1:
The needle assembly is designed as a separable unit that can be detached from the syringe barrel through the needle hub interface. This segmentation allows the needle to be replaced while maintaining the safe retraction mechanism, thus preserving reliability while enabling adaptability for different needle sizes or replacements
Solution Approach 2:
The retainer incorporates a dynamic engagement mechanism where the retaining members can flex or move to allow intentional needle insertion and removal, while automatically engaging to prevent inadvertent proximal movement during injection. This dynamic behavior enables both safe retention and easy replacement
3Reliability
If retainers are designed with multiple retaining members to ensure secure needle engagement, then reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Multiple retaining members are integrated into a single retainer body structure rather than being separate components. This consolidation maintains the secure engagement function of multiple retaining elements while simplifying manufacturing to a single molding or machining operation, reducing production complexity and cost
Solution Approach 2:
The retainer body features localized retaining members positioned at specific locations to provide secure engagement where needed, while other portions of the structure remain simple and easy to manufacture. This selective complexity ensures reliability at critical points without unnecessarily complicating the entire manufacturing process
Data Source
AI summary
A retainer for a needle assembly of a retractable syringe that includes a plunger assembly and a barrel having a mounting member. The needle assembly includes a retractable needle, a needle hub, and a retainer. The retractable needle is engageable by the plunger assembly to facilitate retraction thereof. The needle hub is mountable to the mounting member of the barrel. The retainer includes a body and at least one retaining member that extends distally from the body. The retaining member includes an inwardly projecting lateral projection to engage the retractable needle and thereby prevent inadvertent proximal movement of said retractable needle prior to retraction. A retractable needle assembly includes the retainer, and a retractable syringe includes the retractable needle assembly including the retainer. A syringe kit includes a retractable syringe, a plurality of retractable needle assemblies, and a vial adapter.