Rotating Plunger Rod for Compact Syringe Packaging
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Solution Overview
Problem
Conventional pre-filled syringes have a bulky packaging footprint due to elongated plunger rods, increasing storage space requirements and shipping costs, and are not suitable for compact storage or user portability.
Innovation Solution
A syringe assembly design where the plunger rod transitions from a parallel position to align with the syringe barrel's longitudinal axis, allowing for a compact configuration that reduces the overall length and packaging space, with a plunger assembly that includes a housing, handle, and a tamper-evident mechanism for secure and efficient fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the plunger rod extends elongated from the syringe barrel, then the plunger mechanism can effectively move the stopper through the injection cycle, but the packaged syringe assembly becomes elongated and occupies excessive storage space
Solution Approach 1:
The plunger rod is segmented into a distal end portion and a proximal end portion that can be positioned at different locations relative to the syringe barrel. The distal end portion engages the stopper while the proximal end portion extends outward, allowing the intermediate portion to be repositioned to reduce overall length during packaging while maintaining functional connectivity through the longitudinal axis alignment.
Solution Approach 2:
The plunger rod transitions from a linear extension along the longitudinal axis to a configuration where portions are positioned radially or at angles relative to the barrel. The intermediate portion can be positioned adjacent to the barrel sidewall or at an angle, changing the spatial dimension of the plunger assembly to reduce the elongated footprint while maintaining operational effectiveness through rotational engagement.
2Volume of moving object
If the plunger rod is retracted to reduce length, then packaging footprint is reduced, but the plunger rod must extend sufficiently to engage and move the stopper effectively
Solution Approach 1:
The plunger rod is pre-configured with engagement features at the distal end portion that can effectively engage the stopper even when the overall rod length is reduced. The intermediate portion is preliminarily positioned adjacent to the barrel or at an angle, allowing the distal end to maintain proper engagement geometry with the stopper while minimizing the extended length required for operation.
Solution Approach 2:
The plunger rod intermediate portion can be nested or positioned adjacent to the syringe barrel sidewall, allowing the distal end portion to engage the stopper while the proximal end portion extends outward for actuation. This nesting arrangement reduces the overall elongated footprint by utilizing the space around the barrel rather than extending linearly beyond it.
Data Source
AI summary
A syringe assembly includes a syringe barrel defining a chamber, a stopper disposed within the chamber, and a plunger assembly. The plunger assembly includes an elongated plunger rod, a housing, and a handle portion connecting the plunger rod and housing. The plunger assembly transitions from a first position disposed about the syringe barrel, to a second position with the plunger rod engaged with the stopper. Transition of the plunger assembly includes rotational engagement of the plunger rod and stopper.