Medicament Delivery Device Plunger Rod Guide System
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Solution Overview
Problem
Pre-filled syringes for medicament delivery face challenges in reliably delivering low volumes due to inconsistent plunger deformation and lack of feedback during operation stages, leading to potential medicament loss or excess.
Innovation Solution
A medicament delivery device with a plunger rod and guide system that facilitates controlled displacement and provides tactile and acoustic feedback for precise low-volume delivery, ensuring reliable operation stages through a knob with turn ridges and signage for operator guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the plunger is displaced by a longitudinal impulse to dislodge the seal, then the seal is dislodged from the interior wall, but the operator's control over the plunger displacement is compromised
Solution Approach 1:
A release mechanism acts as an intermediary between the operator and the plunger seal. The mechanism includes a plunger rod with a release feature that engages a cam surface on the syringe body, translating rotational motion into controlled linear displacement to dislodge the seal without requiring direct longitudinal impulse application by the operator
2Productivity
If the plunger bottoming out is used to limit the delivery stroke, then the medicament delivery is completed, but the deformation of the plunger and stopper makes the delivery volume unreliable
Solution Approach 1:
The release mechanism replaces the bottoming-out method by using a cam surface and release feature interaction to precisely control plunger displacement. The cam surface geometry defines the exact delivery stroke length, eliminating reliance on elastic deformation of pliant materials and providing repeatable, precise volume delivery
3Ease of operation
If operator manipulation is used to effect mixing and priming stages, then the syringe is prepared for delivery, but there is no feedback indicating when stages are completed leading to medicament loss or excess
Solution Approach 1:
The release mechanism incorporates tactile feedback through the interaction between the release feature and cam surface. Distinct tactile sensations indicate completion of mixing, priming, and delivery stages, providing the operator with clear information about operation progress without requiring visual inspection or complex indicators
Data Source
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AI summary
Apparatus and methods for medicament delivery. The apparatus may include, and the methods may involve, a delivery device for delivering a target amount of the medicament from a distal end of the device. The device may include a rod for moving a plunger that discharges the medicament from the distal end. The device may avoid or reduce deformation of the plunger during the discharge. The plunger motion may be stopped by detent that interacts with the rod. The apparatus and the methods may provide an operator indication of progress of stages of operation. The device may feature triggers corresponding to stages of medicament displacement from the device, such as pre-delivery stages, including priming.