Autoinjector Door-Driven Spring Mechanism for Battery-Free Dosing
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Solution Overview
Problem
Conventional injection devices, both manual and autoinjectors, pose challenges for users due to the need for manual force application, potential premature dose interruption, and dexterity requirements, while electro-mechanical or fully electronic autoinjectors lack robustness and may require battery replacement.
Innovation Solution
An improved autoinjector design featuring a case with a hingedly coupled door, a plunger driven by a drive spring, a trigger button, and an interlock sleeve mechanism, ensuring consistent dose delivery and user-friendly operation without batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual force is used to drive medicament through a needle, then the device structure is simple, but the ease of operation deteriorates due to requiring continuous button pressing and dexterity
Solution Approach 1:
The patent replaces the manual mechanical button-pressing system with an automated spring-driven mechanical system. The spring mechanism automatically provides the force needed to drive the plunger, eliminating the need for continuous manual button pressing while maintaining a purely mechanical device structure without electronic components.
Solution Approach 2:
The spring is pre-compressed in advance during device assembly or activation, storing mechanical energy that is then released automatically during the injection process. This preliminary action eliminates the need for continuous manual force application during injection, as the pre-loaded spring provides sustained driving force.
2Ease of operation
If a spring mechanism is used to provide injection force, then the ease of operation improves, but the device complexity increases due to additional components
Solution Approach 1:
The patent integrates the spring mechanism directly into the existing plunger and needle assembly, merging the driving force generation with the injection delivery system. This consolidation adds the spring component while minimizing overall device complexity by eliminating the need for separate manual actuation mechanisms.
3Ease of operation
If electro-mechanical or electronic components are used, then the ease of operation improves with precise control, but the reliability deteriorates due to battery replacement needs and component failure
Solution Approach 1:
The patent replaces electro-mechanical and electronic components with a purely mechanical spring-driven system. This substitution eliminates batteries, motors, circuits, and sensors, resulting in a robust device with no electronic failure points while maintaining automated operation through the mechanical spring mechanism.
Solution Approach 2:
The patent employs a single-use disposable design where the entire device including the spring mechanism is discarded after one use. This approach ensures reliability by eliminating the need for battery replacement, calibration, or maintenance of complex components, as each new device provides a fresh, guaranteed-performance system.
4Use of energy by moving object
If the plunger is moved from distal to proximal position, then the drive spring is compressed storing energy, but the force required increases during door rotation
Solution Approach 1:
The patent employs a dynamic door mechanism with hinges and linkages that change the mechanical advantage during rotation. As the door rotates and the plunger moves, the mechanism dynamically adjusts the force application points and leverage, allowing the spring to be compressed effectively while keeping the user-applied force within manageable limits throughout the motion range.
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 reliable, user-friendly medicament administration with enhanced robustness, ensuring complete dose delivery and preventing needle stick injuries, suitable for various user groups including the elderly and children.
Implementation Method 1
at least one drive spring applying a biasing force on the plunger relative to the case
Implementation Method 2
at least one resilient button locking beam disposed in the case and adapted to engage the at least one interlock beam. The interlock beam causes the button locking beam to deflect when the interlock sleeve is in the retracted position
Data Source
AI summary
An autoinjector includes a case, a door hingedly coupled to the case and having an open position and a closed position, a plunger slidably disposed in the case, and at least one drive spring applying a biasing force on the plunger relative to the case, wherein the door is operably coupled to the plunger, and wherein rotation of the door from the closed position to the open position moves the plunger from a distal position in the case to a proximal position in the case and compresses the at least one drive spring.