Syringe Passive Locking Mechanism Prevents Reuse
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Solution Overview
Problem
The reuse of hypodermic syringes without proper sterilization contributes to the spread of diseases, particularly among intravenous drug users, as existing solutions require active user intervention to disable the syringe, and there is a need for a cost-effective, automatic mechanism to prevent reuse and indicate usage.
Innovation Solution
A syringe assembly with a passive locking mechanism that prevents the plunger rod from being reused by locking it within the barrel after an injection cycle, featuring a rib and protrusion system and optional visual indicators to signify usage, ensuring the syringe cannot be disassembled or reused without breaking the plunger rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive locking mechanism is implemented to automatically prevent reuse, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The locking mechanism merges the plunger rod and stopper into a unified system where relative motion between the two components triggers the disabling action. The stopper is attached to the plunger rod in a manner that prevents disassembly, creating an integrated passive locking system that automatically prevents reuse without requiring separate active disabling components.
Solution Approach 2:
The syringe assembly performs the disabling action automatically through its own operational mechanics. During the injection cycle, the stopper and plunger rod move relative to each other, and this relative motion itself triggers the locking mechanism that prevents future use. The system disables itself through its normal operation rather than requiring external intervention.
2Reliability
If the stopper and plunger rod are attached to prevent disassembly, then reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The connection between the stopper and plunger rod is designed to be dynamic rather than static. During the injection cycle, the stopper and plunger rod can move relative to each other, allowing normal operation. After the injection cycle completes, the relative motion triggers the locking mechanism that prevents further disassembly. This dynamic connection maintains ease of operation during use while ensuring reliability after use.
3Loss of information
If visual indicators are added to show usage status, then information completeness is improved, but device complexity increases
Solution Approach 1:
The syringe assembly incorporates visual indicators that change appearance based on usage status. These indicators may involve color changes, opacity changes, or visible structural changes that occur automatically during the injection cycle or locking process, providing clear visual information about whether the syringe has been used without requiring complex electronic or mechanical indicator systems.
Data Source
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AI summary
Syringe assemblies having a passive disabling system to prevent reuse are provided. According to one or more embodiments, the syringe assembly (100) comprises a barrel (120), plunger rod (140) and stopper (160) wherein the plunger rod further comprises a locking protrusion (144) that locks the plunger rod within the barrel. Certain embodiments further include a frangible portion (143) on the plunger rod that breaks when reuse is attempted. One or more embodiments include a plunger rod and stopper attachment that prevents disassembly of the syringe assembly prior to use. Syringe assemblies of one or more embodiments also include visual indicators or markers (300) indicating whether a syringe assembly is used or the plunger rod is locked within the barrel.