Infusion Pump Locking Disc Plunger Rod Alignment
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Solution Overview
Problem
Infusion pump assemblies face challenges in efficiently and reliably administering small, continuous doses of fluids, such as medications, while also allowing for occasional larger doses, due to complexity in loading and engaging the plunger rod with the drive screw, which can lead to misalignment and inefficiencies.
Innovation Solution
The infusion pump assembly incorporates a locking disc and plunger rod system with a clearance hole and notches, allowing the plunger rod to move from a locked to an unlocked position, enabling easy loading and alignment with the drive screw, and a reservoir assembly with alignment tabs for secure engagement, simplifying the loading process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a locking disc with notches and a plunger rod system is used, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is segmented into distinct components: a locking disc with notches, a plunger rod with a head, and a drive screw. This segmentation allows each component to perform its specific function independently, making the loading process more intuitive and easier to operate while maintaining manageable complexity through modular design.
Solution Approach 2:
The plunger rod acts as an intermediary component between the reservoir assembly and the drive screw. Its head engages with the drive screw to transmit rotational motion, while its body passes through the clearance hole in the locking disc. This intermediary mechanism facilitates smooth engagement and alignment during the loading process.
2Manufacturing precision
If alignment tabs and clearance holes are used, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The locking disc features asymmetric notches and the reservoir assembly includes asymmetric alignment tabs that correspond to these notches. This asymmetric design ensures precise angular positioning and alignment during assembly, preventing misalignment while the features are simple to manufacture using standard machining processes.
Solution Approach 2:
The alignment tabs and clearance holes are pre-positioned during manufacturing to ensure correct alignment before assembly. The clearance hole in the locking disc is precisely positioned relative to the notches, and the alignment tabs on the reservoir are pre-configured to match, ensuring accurate alignment is achieved automatically during the loading process without requiring additional adjustment steps.
Data Source
AI summary
An infusion pump assembly includes a locking tab and a pump barrel inside a pump barrel housing, where the pump barrel accommodates a reservoir assembly. The reservoir assembly includes a reservoir and a plunger rod. The infusion pump assembly also includes a locking disc at a terminus of the pump barrel. The locking disc includes a clearance hole for the plunger rod. The locking disc also includes at least one locking tab notch in close proximity with the locking tab. The locking tab is in moveable engagement with the locking tab notch, and the reservoir moves the locking tab from a locked position to an unlocked position when the plunger rod is inserted through clearance hole. The locking disc rotates upon torque being applied to the reservoir assembly, the locking disc rotating from a non-loaded position to a loaded position with respect to the plunger rod and a drive screw.