Disposable Nozzle Frangible Detent for Needleless Injector
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Solution Overview
Problem
Existing needleless injectors require complex procedures to replace disposable nozzles, involving unscrewing and rethreading, which is cumbersome and inefficient.
Innovation Solution
A disposable nozzle assembly with a nozzle holder and a frangible detent mechanism that allows for easy removal and replacement by rotating the nozzle after use, utilizing a tubular holder body with external threads and a cylindrical sleeve with notches for secure mounting and audible verification of new nozzle installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nozzle is retained by an internally threaded cap requiring unscrewing and rethreading, then the nozzle can be securely mounted, but the replacement procedure becomes complex and time-consuming
Solution Approach 1:
The nozzle assembly is segmented into a reusable holder and a disposable nozzle. The holder remains permanently mounted in the injector after the first installation, while only the disposable nozzle needs to be replaced subsequently. This segmentation eliminates the need to unscrew and rethread the holder cap for each nozzle replacement, significantly simplifying the procedure while maintaining secure mounting through the holder's permanent installation.
Solution Approach 2:
The nozzle is designed as a disposable component that is inexpensive to replace. By making the nozzle disposable rather than requiring complex removal and reinstallation procedures, the system prioritizes ease of replacement over reusability of the nozzle itself, resolving the contradiction between secure mounting and ease of operation.
2Ease of operation
If a frangible detent mechanism is used for nozzle attachment, then nozzle replacement becomes simple by rotation, but the mounting structure becomes more complex
Solution Approach 1:
The frangible detent mechanism is designed to break automatically during the nozzle replacement process, eliminating the need for separate locking or unlocking actions. The detent breaks under the natural rotational force applied during nozzle removal, providing a self-service mechanism that simplifies operation without requiring complex additional components.
Solution Approach 2:
The frangible detent is designed to be discarded (broken) during nozzle replacement, while the holder is recovered and retained for future use. This selective discarding of a simple sacrificial component (the detent) enables easy nozzle replacement without requiring complex reversible locking mechanisms.
3Ease of operation
If the holder is permanently mounted in the barrel, then nozzle replacement is simplified, but the initial installation procedure becomes more complex
Solution Approach 1:
The system is segmented into a permanently mounted holder and a replaceable nozzle. The initial complexity of mounting the holder is accepted as a one-time procedure, while subsequent nozzle replacements become simple operations. This segmentation shifts the complexity from repeated operations to a single initial installation, improving ease of operation for the majority of the device's lifecycle.
Data Source
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AI summary
A disposable nozzle for use on the discharge end of the barrel of a needleless injector is threaded onto the front end of a holder mounted in the barrel. A resilient detent extending outwardly at an acute angle from the inner wall of a recess in the rear end of the nozzle repeatedly enters and exits notches in a sleeve on the holder when the nozzle is mounted on the holder providing an audible signal that the nozzle has not been used. Reverse rotation of the nozzle during removal from the holder results in breaking of the detent. Thus, mounting of a used nozzle on the holder would not be accompanied by a signal that the nozzle is unused.