Autoinjector Plunger Tracking With Acoustic Click and Force Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing autoinjectors lack the ability to accurately track the dispensing movement of the plunger rod and ensure sufficient needle insertion depth during medicament delivery, which can result in incomplete dose administration and improper medicament delivery.
Innovation Solution
Incorporating a sensing assembly within the autoinjector that detects audible clicks, vibrations, or sounds generated by the plunger rod movement, and a force sensor to ensure adequate needle insertion, allowing for precise tracking and confirmation of complete dose delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing assembly is added to track plunger rod movement, then dose delivery accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces direct mechanical measurement of plunger rod movement with acoustic field detection. The audible clicker converts mechanical displacement into acoustic signals, which are then detected by a sensor. This substitution allows for more precise and reliable movement tracking while simplifying the overall system architecture compared to direct mechanical linkages.
Solution Approach 2:
The audible clicker acts as an intermediary component between the plunger rod and the sensor. It converts the mechanical motion of the plunger rod into acoustic signals, which serve as an intermediate carrier that the sensor can detect. This intermediary approach enables indirect measurement, improving accuracy while reducing direct mechanical complexity.
2Reliability
If a force sensor is added to detect needle insertion depth, then injection reliability is improved, but device complexity increases
Solution Approach 1:
The force sensor provides real-time feedback on needle insertion force to the control system. When the insertion force exceeds a predetermined threshold, the system confirms proper needle insertion and enables medicament delivery. This feedback mechanism ensures reliable injection by continuously monitoring and verifying insertion depth without requiring complex mechanical depth measurement systems.
3Measurement precision
If audible clicker mechanism is added to track plunger movement, then dose completion verification is improved, but manufacturing complexity increases
Solution Approach 1:
The audible clicker utilizes periodic mechanical engagement and disengagement of the plunger rod with the clicker mechanism, producing discrete audible clicks corresponding to predetermined positions. This periodic action provides clear, countable signals that are easy to manufacture and assemble, while enabling precise verification of dose completion through simple signal counting by the sensor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures accurate delivery of the full medicament dose by tracking plunger rod movement and verifying sufficient needle insertion, enhancing the reliability of autoinjector performance.
Implementation Method 1
A dispensing movement of the plunger rod may deflect the audible clicker causing the audible clicker to produce one or more audible clicks
Implementation Method 2
a sensor configured to detect the one or more audible clicks of the audible clicker as the plunger rod moves
Implementation Method 3
a force sensor configured to detect that an insertion force is greater than a threshold force
Data Source
AI summary
A medicament delivery device includes a housing, a container disposed within the housing and configured to contain medicament, a plunger slidably disposed within the container, a plunger rod configured to push the plunger through the container to dispense the medicament when the container contains medicament, and a gas canister disposed within the plunger rod and containing a compressed gas, wherein the gas canister is configured to release the compressed gas to drive the plunger rod to dispense the medicament out of a distal end of the container.