Injection Device With Plunger Stops for Precise Microdosing
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Solution Overview
Problem
Existing injection devices struggle to accurately administer micro doses of injection solutions, particularly for medical treatments requiring precise dosages, and lack efficient systems for transferring solutions between syringes and devices.
Innovation Solution
An injection device with a plunger stop mechanism and a plunger releasing mechanism, allowing for accurate dosing and reliable transfer of micro doses, using materials like cycloolefin polymer or borosilicate glass, and a Luer taper connection for fluid-tight transfer from syringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the injection device uses a standard syringe for micro dose administration, then the device complexity is low, but the dosing precision is insufficient
Solution Approach 1:
The injection device segments the dosing process into multiple controlled stages using a plunger stop mechanism with multiple stop positions. Each stop position corresponds to a specific dose volume, allowing precise control of the injection amount. The plunger is divided into a movable plunger body and a fixed hub, with the stop mechanism providing discrete positioning points along the injection path.
Solution Approach 2:
The device incorporates pre-set stop positions on the plunger mechanism that are determined during manufacturing. These stop positions pre-define accurate dose volumes, eliminating the need for manual measurement or calculation during administration. The plunger hub includes engagement protrusions that automatically align with corresponding recesses in the stop mechanism, ensuring reproducible dosing.
2Measurement precision
If the injection device includes a plunger stop mechanism for accurate dosing, then the dosing precision improves, but the device complexity increases
Solution Approach 1:
The stop mechanism is merged with the plunger assembly itself rather than being a separate external component. The engagement protrusions on the plunger hub and corresponding recesses in the stop mechanism form an integrated system that provides dosing control directly within the injection device structure, reducing overall complexity.
Solution Approach 2:
The plunger hub serves multiple functions: it provides the sealing surface against the injection solution receptacle, transmits the pushing force from the plunger rod, and incorporates engagement protrusions for the stop mechanism. This multi-functionality reduces the number of separate components needed in the system.
3Reliability
If the injection device uses a Luer taper connection for solution transfer, then the transfer reliability improves, but the device complexity increases
Solution Approach 1:
A filling adapter serves as an intermediary component that connects the syringe to the injection solution receptacle. The adapter includes a Luer taper female connection that receives the syringe needle, and an internal cannula that delivers the solution to the receptacle. This intermediary structure ensures reliable, sterile solution transfer while maintaining simplicity in the overall system.
4Measurement precision
If the injection device is designed for micro dose administration with multiple stop mechanisms, then the dosing accuracy improves, but the ease of operation deteriorates
Solution Approach 1:
The plunger stop mechanism is designed to automatically engage at the predetermined stop positions during the injection process. The operator simply pushes the plunger, and the engagement protrusions on the plunger hub automatically align with and engage the recesses in the stop mechanism at the correct dosing points, eliminating the need for manual intervention or judgment calls during administration.
Data Source
AI summary
An Injection device (10) comprises an injection solution receptacle (30) and a plunger (70) at least a portion of which is slidably received in the injection solution receptacle (30), wherein the plunger (70) is displaceable relative to the injection solution receptacle (30) in a distal direction in order to expel an injection solution contained In the injection solution receptacle (30) from the injection solution receptacle (30). A first plunger stop mechanism (140) is adapted to stop a displacement of the plunger (70) relative to the injection solution receptacle (30) in the distal direction at a first dosing position (P1). A second plunger stop mechanism (140) is adapted to stop a displacement of the plunger (70) relative to the injection solution receptacle (30) from the first dosing position (P1) in the distal direction at a second dosing position (P2), wherein the first and the second dosing position (P2) of the plunger (70) are selected in such a manner that the plunger (70), upon being displaced relative to the Injection solution receptacle (30) between the first and the second dosing position (P2) Is adapted to expel a desired dose of the injection solution contained in the Injection solution receptacle (30) from the injection solution receptacle (30).