Spring-Driven Autoinjector for Complete, Low-Effort Dosing
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Solution Overview
Problem
Conventional injection devices, both manual and autoinjectors, pose challenges for users lacking dexterity, such as the elderly or children, due to the need for continuous force application and alignment during injections, which can lead to incomplete dosing and difficulty in administering medications.
Innovation Solution
An autoinjector design featuring a telescopic needle shroud, a carrier system with a compliant beam mechanism, and a control spring mechanism that ensures consistent injection force and alignment, allowing for a trigger-activated delivery of medication without requiring continuous user effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If manual force is used to drive medicament through a needle, then the injection can be administered, but the force required may be too high for elderly or child users
Solution Approach 1:
The patent replaces the manual mechanical pushing system with an automated spring-driven plunger mechanism. The spring automatically generates the necessary injection force without requiring continuous manual effort from the user, thereby substituting human mechanical effort with an automated mechanical system.
Solution Approach 2:
The injection device performs the injection action autonomously once activated. The spring mechanism self-generates the force needed to push the plunger and deliver the medicament, eliminating the need for the user to continuously apply force during the injection process.
2Reliability
If a button/plunger is used for manual injection, then the injection can be administered, but the injection may stop if the button is released prematurely
Solution Approach 1:
The spring-driven plunger mechanism ensures continuous force application throughout the entire injection process. Once activated, the spring continuously pushes the plunger forward without interruption, eliminating the risk of premature release stopping the injection and ensuring complete dose delivery.
Solution Approach 2:
The spring mechanism autonomously maintains continuous force on the plunger throughout the injection, eliminating the need for the user to continuously hold or press the plunger. The system self-regulates the force application to ensure reliable and complete medicament delivery.
3Manufacturing precision
If alignment and stillness during injection are required, then proper injection can be achieved, but users lacking dexterity may struggle
Solution Approach 1:
The device is pre-configured with the needle, medicament container, and spring mechanism in the correct positions before use. The user simply needs to attach the device to the injection site and activate it, eliminating the need for complex alignment maneuvers during the injection process.
Solution Approach 2:
The autoinjector mechanism automatically maintains proper alignment and stability during injection. The spring-driven system self-regulates the injection force and direction, reducing the user's need for manual dexterity to keep the device steady or aligned during the procedure.
4Reliability
If a telescopic needle shroud with multiple positions is used, then proper needle protection and deployment can be achieved, but the device complexity increases
Solution Approach 1:
The needle shroud is designed as a telescopic structure that nests within itself or within the device housing when not in use. This nested configuration provides compact storage and protection for the needle while allowing easy deployment when needed, reducing overall device complexity despite the multiple functional positions.
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
The autoinjector provides a reliable and user-friendly injection experience by ensuring complete dose delivery and proper alignment, reducing the risk of incomplete injections and improving usability for individuals with limited dexterity.
Implementation Method 1
a drive spring biasing the plunger relative to the carrier
Implementation Method 2
The carrier includes a compliant beam having a boss adapted to engage an opening in the plunger when the carrier is in the first axial position
Data Source
AI summary
An autoinjector includes a case, a needle shroud telescopically coupled to the case, a carrier slidably arranged in the case, a collar rotatably and slidably disposed in the case and coupled to the needle shroud and the carrier, and a trigger button operably coupled to the carrier. The case includes a rib. The needle shroud is movable between a first extended position, a retracted position, and a locked second extended position. The carrier is adapted to hold a medicament container and movable from a first axial position to a second axial position relative to the case. The carrier abuts the rib in the first axial position and the needle shroud is in the first extended position and disengages the rib when the needle shroud is in the retracted position and the trigger button is pressed to advance the carrier to the second axial position.