Spring-Driven Autoinjector With Telescopic Needle Shroud
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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 doses and difficulty in administering medications.
Innovation Solution
An autoinjector design featuring a telescopic needle shroud, a carrier with a compliant beam, and a rotatable collar mechanism, utilizing springs for automatic dose delivery, ensuring proper alignment and preventing premature injection cessation, with visual feedback for dose progress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual force is used to drive medicament through a needle, then the injection device can be simple in structure, but the user requires continuous force application and dexterity which may be too difficult for elderly or children
Solution Approach 1:
The injection device uses a spring mechanism that automatically provides the force needed to drive the medicament through the needle. The user simply needs to activate the mechanism, and the spring self-generates the propulsion force, eliminating the need for continuous manual force application during injection.
Solution Approach 2:
The spring is pre-loaded and stored in a compressed state before use. This preliminary action stores energy that is then released during injection to automatically propel the medicament, removing the need for the user to generate force during the actual injection process.
2Ease of operation
If a spring mechanism is used to provide automatic injection force, then ease of operation is improved, but the device complexity increases with additional components like collar and needle shroud
Solution Approach 1:
The collar and needle shroud are combined into a single integrated component that performs multiple functions: it guides the needle, protects the user during insertion, and interfaces with the carrier mechanism. This merging reduces the total number of separate parts while maintaining automatic injection functionality.
Solution Approach 2:
The needle shroud serves multiple purposes: it acts as a protective barrier during needle insertion, a guide for accurate positioning, and a structural element that interfaces with the carrier. This multi-functionality reduces the need for separate dedicated components for each function.
3Object-affected harmful factors
If the needle shroud is extended for protection during storage, then user safety is improved, but the injection mechanism requires additional space and structural complexity
Solution Approach 1:
The needle shroud is telescopically coupled to the carrier, allowing it to nest within the carrier body when not in use. This nested configuration minimizes the overall volume required for storage while providing full extension for protection during handling and injection.
Solution Approach 2:
The needle shroud transitions from a static extended protective position during storage to a dynamic retracted position during injection. This dynamic adjustment optimizes the volume requirements at different stages of the device lifecycle.
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 user-friendly, reliable, and complete medication delivery system, suitable for diverse user groups, with visual confirmation of dose administration and prevention of premature release, enhancing injection accuracy and ease.
Implementation Method 1
a drive spring biasing the plunger relative to the carrier
Implementation Method 2
a control spring biasing the needle shroud between a first extended position and a second retracted position
Implementation Method 3
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.