Disposable Syringe Spacer Assembly for Low Dead Space Needle Shielding
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Solution Overview
Problem
Existing hypodermic needle and syringe assemblies retain significant volumes of pharmaceutical material after use, leading to waste and increased risk of needle stick injuries due to integrated safety mechanisms taking up additional space.
Innovation Solution
A syringe system with a tubular spacer and safety sheath mechanism that automatically shields the needle after use, minimizing residual material by allowing the plunger to displace the spacer and sheath, ensuring complete discharge of the contents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an integrated safety mechanism is added to the needle head, then needle stick injury risk is reduced, but the dead space in the needle head increases causing more residual pharmaceutical to be retained
Solution Approach 1:
The safety mechanism is extracted from the needle head and relocated to the syringe barrel. A safety shield is positioned in the barrel that can move independently of the needle assembly, allowing the needle head to maintain minimal dead space while the safety function is preserved in a separate location.
Solution Approach 2:
A tubular spacer is introduced as an intermediary component between the plunger and the safety shield. The spacer transmits the pushing force from the plunger to advance the safety shield, while also providing a pathway for the plunger to contact and displace residual material in the process.
2Loss of substance
If the plunger is designed to contact and displace the tubular spacer, then complete discharge of pharmaceutical material is achieved, but the device complexity increases
Solution Approach 1:
Multiple functions are merged into the tubular spacer: it acts as a mechanical connector between the plunger and safety shield, serves as a conduit for force transmission, and provides a pathway for displacing residual material. This consolidation reduces the number of separate components needed.
Solution Approach 2:
The tubular spacer performs multiple functions simultaneously: it transmits the pushing force from the plunger to advance the safety shield, provides structural support within the barrel, and creates a flow path for complete discharge of pharmaceutical material through the needle.
3Reliability
If a safety sheath mechanism is integrated into the needle head, then needle shielding is improved, but the volume available for pharmaceutical discharge is reduced
Solution Approach 1:
The syringe assembly is segmented into distinct functional zones: the needle head for injection, the tubular spacer for force transmission, the safety shield for protection, and the barrel for material containment. This segmentation allows each component to be optimized for its specific function without compromising others.
Solution Approach 2:
The safety shielding function is moved from the horizontal plane (within the needle head) to the longitudinal dimension (within the barrel). The safety shield travels along the barrel's length, advancing to cover the needle after injection, thereby preserving the needle head's volume for complete pharmaceutical discharge.
Data Source
AI summary
A system with a needle head that attaches to a syringe assembly. The syringe assembly contains a barrel and a plunger. The plunger has a bore opening that is accessible from within the barrel. A tubular spacer is disposed within the barrel. The tubular spacer defines a central opening. The needle head has a needle that extends from a needle base. The needle base extends into the central opening of the tubular spacer. A plug is provided that blocks access to the needle. The plug is displaced out of the central opening of the tubular spacer and into the opening in the plunger as the plunger contacts and displaces the tubular spacer in the barrel. As the plug is displaced from the tubular spacer, the plug transfers into the bore opening within the plunger. This enables the plunger to press flush against the tubular spacer.