Disposable Syringe Tip Separation Mechanism for Single-Use Safety
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Solution Overview
Problem
There is a need for a safety syringe for needleless injectors that can be used once and only once, as existing solutions do not effectively prevent re-use.
Innovation Solution
A disposable syringe design featuring a tubular body with a piston that, when fully pushed in, separates a tip to seal the orifice, preventing re-use by leaving it inside the syringe body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a syringe is designed for needleless injection, then ease of operation is improved, but reliability of single-use prevention deteriorates
Solution Approach 1:
The syringe is divided into separable components: a reusable barrel and a disposable cartridge containing the piston and tip. The tip is designed as a separate element that can be detached from the piston, allowing the piston to be removed while the tip remains sealed in the cartridge. This segmentation enables single-use prevention while maintaining ease of operation through the needleless design.
Solution Approach 2:
The tip is pre-attached to the piston in a separable manner before use. During the injection process, the tip automatically separates from the piston when the piston is fully pushed in, preliminarily sealing the orifice. This preliminary action ensures that the syringe cannot be reused, as the tip remains detached and blocking the fluid path.
2Reliability
If a tip separation mechanism is added to prevent re-use, then reliability is improved, but device complexity increases
Solution Approach 1:
The tip separation mechanism utilizes the natural segmentation of the syringe into modular components. The tip is designed as a separate element that attaches to the piston during assembly but automatically detaches when the piston is fully inserted. This segmentation approach prevents re-use without requiring complex mechanical locking or sealing mechanisms.
Solution Approach 2:
The tip separation mechanism is self-actuating based on the injection process itself. When the piston is pushed fully into the barrel, the mechanical action automatically causes the tip to separate from the piston and remain in the barrel, sealing the orifice. No additional actuators, sensors, or control systems are required—the injection action itself triggers the single-use prevention mechanism.
3Reliability
If the tip remains in the body after ejection, then single-use functionality is ensured, but loss of substance occurs
Solution Approach 1:
The syringe cartridge containing the piston and tip is designed as a disposable component that is discarded after a single use. The tip remains in the barrel after ejection, and the entire cartridge is thrown away rather than attempting to recover or clean the tip. This approach accepts the loss of the tip material as necessary to ensure single-use functionality and prevent contamination.
Solution Approach 2:
The design discards the tip in the barrel after use rather than attempting to retrieve or reuse it. The cartridge is designed to be disposed of as a complete unit, with the tip remaining sealed in the barrel. This discarding approach ensures that no residual fluid or contamination remains in the tip, guaranteeing single-use functionality while accepting the material loss.
Data Source
AI summary
A disposable syringe for use in a needleless injector includes a tubular body with an open rear end, a closed front end containing an injection orifice, a chamber in the body for receiving a liquid and a plunger slidable in the chamber for pushing the liquid out of the orifice. A tip is provided on the inner end of the plunger for separation from the remainder of the plunger to block the orifice when the plunger is retracted after an injection, whereby the syringe cannot be re-used.