Replaceable Needle Assembly for Retractable Syringe
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Solution Overview
Problem
Existing syringes with fixed needles or specialized needle assemblies are not amenable to replacing bent or burred needles or allowing selection of alternative needle sizes, posing risks of re-use and needle stick injuries.
Innovation Solution
A retractable syringe with a replaceable needle assembly and improved plunger seal, featuring a mounting member with screw threads for easy needle exchange and a plunger with a biasing mechanism for efficient needle retraction, allowing users to select needle sizes and replace damaged needles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If syringes have fixed needles or highly specialized needle assemblies, then needle stick injury prevention is improved, but needle replacement capability deteriorates
Solution Approach 1:
The syringe is divided into separable components: a reusable barrel assembly and replaceable needle assemblies. The needle assembly can be detached and replaced independently, allowing the safe retraction mechanism to be retained while enabling needle replacement for different sizes or after damage.
Solution Approach 2:
The barrel assembly is designed with a universal mounting interface that can accommodate multiple types of needle assemblies. The mounting member with screw thread and retaining features provides a standardized connection that works with various needle configurations, making the system multi-functional.
2Reliability
If syringes provide needle sheathing or retraction mechanisms, then safety is improved, but needle replacement amenability deteriorates
Solution Approach 1:
The needle assembly incorporates a dynamic retraction mechanism where the needle can be automatically retracted into the barrel upon activation. This dynamic feature maintains safety while the modular design allows the entire needle assembly to be replaced as a unit, combining safety with replacement capability.
Solution Approach 2:
The needle assembly is pre-configured with mounting features including screw threads and retaining structures that enable easy attachment and detachment. The preliminary design of these engagement features allows users to replace needles without complex tools or procedures, maintaining ease of replacement while incorporating safety mechanisms.
3Adaptability or versatility
If a replaceable needle assembly is added, then needle selection flexibility is improved, but device complexity increases
Solution Approach 1:
By segmenting the syringe into a barrel assembly and separate needle assemblies, the system gains flexibility to use different needle types and sizes with a single reusable barrel. The complexity is localized to the replaceable needle component rather than the entire device.
Solution Approach 2:
The barrel assembly serves as a universal platform that can accept multiple needle assembly variants through a standardized mounting interface. This universality reduces overall system complexity by maintaining a common barrel design while allowing needle variety, rather than designing separate syringes for each needle type.
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 enables safe and efficient needle replacement, preventing re-use and needle stick injuries while improving fluid delivery efficiency through a collapsible seal mechanism.
Implementation Method 1
a biasing means; wherein the plunger inner and plunger outer co-operate to maintain said biasing means in an initially energized state prior to retraction
Implementation Method 2
a collapsible seal mounted to the plunger inner; wherein the plunger inner and plunger outer co-operate to maintain said biasing means in an initially energized state prior to retraction
Data Source
AI summary
A replaceable needle assembly is provided for a retractable syringe comprising a barrel and a plunger, whereby the retractable needle can be replaced by a user without affecting the retraction mechanism. A mounting member is removably mountable to the barrel by way of a screw-thread connection and a needle mount is removably coupled to the mounting member. A needle is mounted to the needle mount. The barrel comprises a needle mount retainer that comprises a plurality of fingers that engage the retractable needle mount to prevent inadvertent retraction. The plunger comprises a collapsible seal which maximizes the efficiency of fluid delivery prior to the plunger engaging the retractable needle mount for retraction. An initially compressed spring decompresses to drive retraction of the plunger and the engaged needle mount. A lock formed between the plunger and barrel prevents further use of the plunger after retraction.