Reusable Auto-Injector Gas Spring Engine
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Solution Overview
Problem
Current auto-injector devices face challenges such as user discomfort due to manual operation requirements, potential for incomplete doses, and safety issues like needle stick injuries, particularly for elderly or dexterity-impaired individuals, as well as inefficiencies in syringe retraction and dosage accuracy.
Innovation Solution
A reusable engine for auto-injectors utilizing a gas spring mechanism with a cylinder and piston, allowing for compact design, consistent injection force, and safe needle retraction, combined with a trigger button and locking mechanism to ensure proper operation and prevent accidental injections, along with a syringe spring for reliable retraction and emptying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual button/plunger is used to drive the fluid through the needle, then the device structure is simple, but the user experiences high injection forces and potential for incomplete doses
Solution Approach 1:
The patent replaces the manual mechanical button/plunger system with an automatic spring-driven mechanical system. The spring mechanism automatically provides the force needed to drive the stopper and deliver the full dose without requiring continuous manual pressure, thereby eliminating the risk of incomplete doses while maintaining mechanical simplicity.
Solution Approach 2:
The spring is pre-compressed before use, storing mechanical energy in advance. When activated, this pre-stored energy automatically drives the injection process to completion without requiring the user to maintain continuous manual force, ensuring the full dose is delivered reliably.
2Force
If a spring mechanism is used to provide injection energy, then injection force consistency is improved, but the device complexity increases
Solution Approach 1:
The spring mechanism serves multiple functions: it provides the driving force for injection, automatically retracts the needle after delivery, and can be integrated with the syringe assembly. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall device complexity despite the added spring mechanism.
Solution Approach 2:
The spring mechanism is combined with the syringe and needle assembly into an integrated engine unit. The spring, stopper, and needle retraction mechanism are merged into a single cohesive system, reducing the number of separate components and simplifying the overall structure despite the enhanced functionality.
3Speed
If the needle remains exposed after injection, then quick access is possible, but needle stick injury risk increases
Solution Approach 1:
The spring mechanism is pre-loaded to automatically perform the needle retraction action immediately after the injection is complete. This preliminary programming of the retraction sequence ensures the needle is quickly and automatically hidden without requiring manual intervention, eliminating the exposure risk while maintaining operational speed.
Solution Approach 2:
The same spring force that drives the injection forward is also used to automatically retract and hide the needle after delivery. The harmful aspect of needle exposure is converted into a beneficial automatic retraction mechanism, where the injection force mechanism doubles as a safety mechanism.
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 gas spring engine provides a compact, consistent injection force, reduces user discomfort, ensures complete dose delivery, and safely retracts the needle, enhancing user safety and dosage accuracy while preventing needle stick injuries.
Implementation Method 1
drive means arranged as a gas spring comprising a cylinder and a piston with a plunger for transmitting the spring force. A compressed gas is provided in a high pressure cavity defined between the piston and a distal end of the cylinder
Implementation Method 2
The syringe and the needle are arranged to be hidden inside the packaged syringe when the drive means is in its loaded state. The syringe is biased in distal direction by a syringe spring
Data Source
AI summary
An engine for an-auto injector for administering a dose of a liquid medicament includes a case arranged to be attached to a package syringe containing a syringe. The case contains a drive capable of, upon activation, pushing the needle from a covered position into an exposed position, and operating the syringe to supply the dose of medicament. The case contains a trigger arranged to lock the drive in a loaded state prior to manual operation and capable of, upon manual operation, releasing the drive for injections. The drive is arranged as a gas spring including a cylinder and a piston with a plunger for transmitting the spring force. A latch is arranged for preventing translating between the cylinder and the case. The latch is disengageable by the released gas spring being at least nearly fully extended thus allowing the extended gas spring to be translated in a distal direction.