Linear Shuttle Pump Detent Positioning for Wearable Drug Delivery
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Solution Overview
Problem
Wearable drug delivery devices face inaccuracies in small drug volume delivery due to variations in drive mechanism performance, affecting dosage regulation and sequencing.
Innovation Solution
Incorporating a detent apparatus with a detent body, detent arm, and detent engagement member, coupled with a piston grip, to control the axial movement of the piston within the pump chamber, ensuring precise drug delivery and sequencing through mechanical, optical, or capacitive sensing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drive mechanism is used to expel liquid drug from the reservoir, then the pump can deliver the drug, but delivery rate accuracy suffers when the volume of drug is small due to variations in drive mechanism performance
Solution Approach 1:
The pump chamber is pre-filled with a precise volume of liquid drug from the reservoir before the delivery phase. This preliminary filling action ensures that the exact required dosage is prepared in advance, eliminating accuracy issues during the actual delivery process. The detent apparatus then ensures this pre-measured volume is delivered precisely.
Solution Approach 2:
The patent replaces continuous mechanical drive mechanism actuation with a discrete detent-based positioning system. The detent engagement member interacts with arrest locations on the piston to precisely control piston position at key points in the cycle, substituting the need for highly precise continuous mechanical drive control with a simpler discrete positioning mechanism that ensures accurate small volume delivery.
2Measurement precision
If a detent apparatus is added to control piston positioning, then delivery accuracy improves, but device complexity increases
Solution Approach 1:
The detent apparatus is integrated into the existing pump structure, with the detent engagement member and arrest locations incorporated into the piston and pump chamber assembly. This merging of the positioning mechanism with the existing mechanical components adds functionality without proportionally increasing overall device complexity.
Solution Approach 2:
The detent apparatus is designed to be passively actuated by the natural motion of the piston during its cycle. The detent engagement member automatically engages with the arrest locations at the appropriate points in the piston stroke, eliminating the need for additional actuators or complex control mechanisms to position the piston.
3Reliability
If mechanical sensing mechanisms are used to verify drive mechanism positioning, then sequencing accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses the mechanical detent engagement itself as the sensing mechanism. The engagement and disengagement of the detent engagement member with the arrest locations provides inherent mechanical feedback on piston position and sequencing, eliminating the need for separate electronic or optical sensing systems and their associated manufacturing complexities.
Data Source
AI summary
Disclosed herein are wearable drug delivery devices and methods for component positioning of a linear shuttle pump. In some approaches, a pump may include a pump chamber operably coupled with a piston, and a detent apparatus, wherein the detent apparatus comprises a detent body, a detent arm, and a detent engagement member. The detent engagement member may be retained in direct physical contact with first or second arrest locations of either the detent body or the detent arm. The pump may further include a piston grip coupled to the piston, the piston grip including a grip component engaged with an exterior of the piston. Movement of the piston grip may cause the piston to move axially relative to the pump chamber to control receipt and delivery of a liquid drug.