Passive Syringe Lock Mechanism to Prevent Premature Reuse
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Solution Overview
Problem
Existing single-use syringes require active locking mechanisms that rely on medical practitioner commitment, and there is a risk of unintentional reuse, leading to potential disease transmission and CRBSI.
Innovation Solution
A self-actuated, passive syringe lock that engages automatically upon plunger advancement, preventing reuse by locking the plunger in the advanced position after medication administration, using a pivoting syringe lock with cantilever forks and plunger detents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active locking or destruction procedures are used to prevent syringe reuse, then syringe inoperability is achieved, but medical practitioners must take active steps which can be inadvertently bypassed
Solution Approach 1:
The syringe lock mechanism is self-actuating and automatically locks the plunger in the advanced position after medication dispensing. The lock engages with the plunger detent without requiring any active steps by the medical practitioner, making the syringe inoperable for reuse automatically. This eliminates the risk of inadvertent bypassing associated with manual locking procedures.
2Extent of automation
If passive syringe lock is used to prevent reuse, then automatic locking is achieved, but the lock mechanism complexity increases
Solution Approach 1:
The lock mechanism is segmented into distinct functional components: a lock body with a cam surface, a plunger detent with a locking surface, and a spring-loaded engagement system. This segmentation allows each component to perform its specific function independently while working together to achieve automatic locking, managing complexity through functional decomposition.
Solution Approach 2:
The cam surface acts as an intermediary between the plunger advancement motion and the lock engagement. As the plunger advances, the cam surface guides and transforms the linear motion into the rotational or positional change needed to engage the detent, simplifying the overall mechanism by using a geometric intermediary rather than complex linkages.
3Reliability
If the syringe lock engages automatically upon plunger advancement, then reuse prevention is ensured, but the risk of premature locking increases
Solution Approach 1:
The lock mechanism is designed with a preliminary engagement phase where the lock fork initially contacts the plunger rod before reaching the detent. This preliminary contact allows the mechanism to verify proper plunger advancement and alignment before final locking occurs, preventing premature engagement due to improper positioning or insufficient advancement.
Solution Approach 2:
The lock mechanism incorporates dynamic elements including a spring-loaded fork that can accommodate variations in plunger advancement timing and position. The spring allows the fork to flex and adjust during the locking process, ensuring reliable engagement only when the plunger reaches the correct advanced position, thereby preventing premature locking.
Data Source
AI summary
A single-use medical syringe has a syringe lock that prevents repeated syringe aspiration and dispensing of fluids to patients. A pivoting syringe lock is coupled to the proximal open end of the syringe barrel. The syringe lock has or more cantilever lock forks in continuous, biased, sliding, abutting contact with the plunger. Each lock fork engages a corresponding plunger detent oriented on a proximal end of the syringe plunger, after the plunger is fully advanced within the syringe barrel. The plunger remains locked in an advanced position within the syringe barrel while each lock fork is engaged in its corresponding plunger detent. In some embodiments, a removeable plunger clip is coupled to the syringe to prevent inadvertent advancement of the plunger into the syringe barrel and premature locking of the syringe prior to administration of medication to a patient.