Telescopic Needle-Shroud Autoinjector for Complete Dose Delivery
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Solution Overview
Problem
Conventional manual injection devices require manual force and dexterity, posing challenges for elderly, children, and arthritic patients, while autoinjectors may not ensure complete dose delivery and can be complex to use.
Innovation Solution
An autoinjector design featuring a telescopic needle shroud, a carrier, a collar, and a trigger mechanism with compliant beams and springs, allowing for controlled medicament delivery with a simple, reliable, and dose-completing injection process.
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 autoinjector device automatically administers the injection without requiring manual force from the user. The spring mechanism self-activates to drive the plunger, eliminating the need for the user to apply force to a button or plunger.
Solution Approach 2:
The manual mechanical system of pushing a button or plunger is replaced with an automated spring-driven mechanical system. The spring stores and releases energy to automatically drive the plunger through the medicament, substituting user-applied force with pre-loaded spring force.
2Reliability
If a button/plunger is continuously pressed during injection, then the injection can be maintained, but premature release will stop the injection and may not deliver the intended dose
Solution Approach 1:
The injection process is made self-regulating through the spring mechanism. Once activated, the spring automatically drives the plunger to complete the full injection without requiring continuous user input or monitoring, ensuring the entire dose is delivered even if the user releases the device prematurely.
Solution Approach 2:
The spring is pre-loaded with energy before use, storing the force needed to drive the plunger through the entire medicament volume. This preliminary energy storage ensures that once triggered, the injection will complete automatically without requiring sustained user action.
3Manufacturing precision
If aligning and holding the injection device still during injection is required, then accurate dosing can be achieved, but users with limited dexterity (elderly, children, arthritic patients) may not have the required dexterity
Solution Approach 1:
The device self-aligns and self-holds during the injection process. The telescopic needle shroud and carrier mechanism automatically maintain proper alignment and positioning without requiring the user to manually hold the device steady, eliminating the dexterity requirement for stabilization.
Solution Approach 2:
The device is divided into functional segments (case, needle shroud, carrier, plunger) that can move independently to achieve alignment and maintain positioning automatically. This segmentation allows each component to perform its specific function without requiring coordinated manual control from the user.
4Ease of operation
If a telescopic needle shroud with multiple positions is used, then controlled medicament delivery is achieved, but the device complexity increases
Solution Approach 1:
Multiple functions (needle protection, alignment, injection control, retraction) are merged into a single telescopic needle shroud component. This integration reduces the number of separate parts needed while achieving controlled medicament delivery through the telescopic mechanism's inherent positional control.
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
Facilitates easy and reliable self-administration of injections by ensuring complete dose delivery with tactile and visual feedback, suitable for users with limited dexterity, and preventing premature injection stoppage.
Implementation Method 1
a drive spring biasing the plunger relative to the carrier
Implementation Method 2
a control spring biasing the needle shroud in a distal direction relative to the case
Implementation Method 3
The carrier includes a compliant beam having a boss adapted to engage an opening in the plunger
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.