Telescoping Plunger Rod for Compact Pre-filled Syringe Storage
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Solution Overview
Problem
Conventional pre-filled syringes face challenges in reducing storage space requirements and preventing tampering, as they often have a large packaging footprint and are susceptible to unintended actuation or tampering.
Innovation Solution
A pre-filled syringe assembly with a telescopic plunger rod and a stop member that limits outward travel, combined with a molded cover and tear tab for tamper-proofing, allowing for a smaller footprint and secure handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional plunger rod design is used, then the syringe can be easily manufactured and operated, but the packaging footprint is large increasing storage space requirements
Solution Approach 1:
The plunger rod is designed as a telescopic mechanism where an inner plunger rod is nested within an outer plunger rod. The inner rod can extend and retract within the outer rod, allowing the plunger mechanism to collapse into a compact configuration for storage while maintaining full functionality during use. This nesting arrangement significantly reduces the packaging footprint compared to conventional rigid plunger designs.
Solution Approach 2:
The plunger rod transitions from a static rigid structure to a dynamic telescopic mechanism that can change its configuration between extended and collapsed states. This dynamic capability allows the plunger rod to adapt its size based on operational needs, providing a compact form factor for storage while maintaining ease of operation during injection.
2Ease of operation
If the plunger rod is made easily removable for user convenience, then operation is simplified, but tampering and unintended actuation become more likely
Solution Approach 1:
The plunger rod assembly is segmented into distinct components: an inner plunger rod, an outer plunger rod, and a retention member. This segmentation allows the inner rod to be retained within the outer rod through a controlled retention mechanism that prevents accidental removal while allowing intentional extraction when needed. The segmented design provides both security against tampering and ease of operation through a well-defined interaction interface.
Solution Approach 2:
A retention member acts as an intermediary element between the inner and outer plunger rods. This retention member provides a controlled retention mechanism that prevents unintended removal of the inner rod while allowing deliberate extraction when required. The retention member mediates between the conflicting requirements of security and ease of operation, providing a reliable yet user-friendly solution.
3Reliability
If a secure retention mechanism is implemented to prevent tampering, then reliability is improved, but the device complexity increases
Solution Approach 1:
The retention function is extracted as a separate, dedicated retention member rather than being integrated into the plunger rod structure itself. This extraction allows the retention mechanism to be designed as a simple, specialized component that provides secure tamper prevention without adding significant complexity to the overall device. The retention member can be easily manufactured and assembled, providing reliable security with minimal added complexity.
Data Source
AI summary
A syringe assembly including a syringe barrel having a first end, a second end, and a sidewall extending therebetween defining a chamber is disclosed. The syringe assembly includes a stopper disposed within the chamber of the syringe barrel and a plunger rod having an inner member engaged with the stopper and an outer member adapted for telescopic movement with respect to the inner member. The plunger rod is transitionable from a collapsed position, in which a portion of the inner member is nested within the outer member, to an extended position, in which the same portion of the inner member extends outside the outer member. The syringe assembly also includes a stop member configured for cooperation with a portion of the syringe barrel, upon relative movement of the outer member with respect to the inner member, to limit the outward travel of the plunger rod from the syringe barrel.