Adjustable Syringe Plunger Stroke Limiter for Defined Dosing
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Solution Overview
Problem
Existing syringes require multiple sizes to accommodate varying medical product doses for different patients, leading to increased manufacturing, storage, and handling costs, and there is a need for a reliable method to deliver a defined dose with minimal resource expenditure.
Innovation Solution
A plunger assembly with a user-adjustable plunger stroke limiter that allows for customizable dose delivery by adjusting the position of the plunger stroke limiter relative to the stopper mount portion, enabling precise control over the injected volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple syringe sizes are used to accommodate varying medical product doses, then the ability to deliver precise doses for different patients is improved, but manufacturing, storage, and handling costs increase
Solution Approach 1:
The syringe is designed with a universal barrel and needle assembly that can accommodate multiple dose volumes (0.5mL, 1mL, 1.5mL, 2mL) by simply replacing the plunger rod and stopper components. This multi-functionality allows a single syringe design to serve multiple dose requirements, eliminating the need for separate syringe sizes for different volumes.
Solution Approach 2:
The syringe is divided into modular components: a universal barrel assembly and interchangeable plunger rod-stopper sets. Each plunger rod-stopper combination is designed with specific stroke lengths corresponding to different dose volumes. This segmentation allows health professionals to select and assemble the appropriate components for the required dose without managing multiple complete syringe units.
2Measurement precision
If different sets of syringes are manufactured for different doses, then dose precision is improved, but manufacturing and storage resources are consumed
Solution Approach 1:
A single universal barrel assembly can deliver multiple precise doses (0.5mL, 1mL, 1.5mL, 2mL) by using different plunger rod-stopper combinations. The barrel is designed with volume markings and a uniform cross-section to ensure accurate volume measurement regardless of which plunger components are used, maintaining dose precision while reducing manufacturing resources.
Solution Approach 2:
The dose volume is controlled by changing the stroke length parameter of the plunger rod-stopper assembly rather than changing the entire syringe. Each plunger rod is designed with a specific length that, when combined with the stopper, delivers a predetermined volume. This parameter-based approach maintains measurement precision while using the same barrel and needle components across all dose configurations.
3Ease of manufacture
If a fixed-size syringe is used for all patients, then manufacturing and storage costs are reduced, but the ability to deliver patient-specific doses is limited
Solution Approach 1:
The syringe system is segmented into a standardized barrel assembly and multiple plunger rod-stopper variants. The barrel, needle, and hub components remain identical across all configurations, simplifying their manufacturing. The plunger rods are produced in different lengths corresponding to specific doses, allowing easy customization while maintaining production efficiency for the common components.
Solution Approach 2:
The syringe system transitions from a static, fixed-dose design to a dynamic, configurable system. The plunger rod-stopper assemblies can be selected and assembled based on the required dose, allowing the same physical syringe platform to adapt to different patient needs. This dynamic configuration capability is achieved through standardized interfaces that enable quick assembly of the appropriate plunger components with the universal barrel.
Data Source
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AI summary
The invention relates to a plunger assembly (104) for a syringe assembly (100) comprising a syringe body (102), wherein the plunger assembly (104) comprises: - a plunger rod (102) extending along a longitudinal axis (A) and having a proximal end (126) and a distal end (123); - at the distal end of the plunger rod, a stopper mount portion (123) for receiving a stopper (124); characterized in that the plunger assembly (104) comprises a plunger stroke limiter (128, 158), in that the position of the plunger stroke limiter (128, 158) with respect to the stopper mount portion (123) is user-adjustable along the longitudinal axis, and in that the plunger stroke limiter (123) is configured to abut against a syringe body abutment surface (130) of the syringe body (102) for at least one position of the plunger stroke limiter (128, 158) with respect to the stopper mount portion (123).