Reusable Auto-Injector with Self-Resetting Spring Mechanism
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Solution Overview
Problem
Existing epinephrine auto-injectors are single-use devices, making them costly and inaccessible to many, as they require replacement after a single dose, with only 0.3 mL of the solution being administered effectively while 1-2 mL remains unused, and current designs complicate reuse.
Innovation Solution
A reusable and resettable auto-injector design featuring a spring-loaded mechanism that allows re-compression for multiple uses, with a removable cap for easy replacement of the syringe and needle, enabling users to administer multiple doses without the need for a new device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-use auto-injector design is used, then reliability is ensured for each dose, but cost increases and accessibility decreases due to frequent replacements
Solution Approach 1:
The device is divided into separable components: a reusable housing containing the actuation mechanism and a replaceable cartridge containing the medicament. This segmentation allows the expensive actuation mechanism to be reused while only the cheaper cartridge is replaced, reducing overall cost and improving accessibility while maintaining reliability through dedicated single-use cartridges.
Solution Approach 2:
The design enables recovery and reuse of the actuation mechanism (housing, spring, trigger assembly) while the consumable cartridge is discarded after single use. This recovers the high-cost components for multiple uses, significantly reducing per-dose cost while maintaining the reliability of each individual dose through sealed, single-use cartridges.
2Ease of manufacture
If a reusable auto-injector design is implemented, then cost decreases through multiple uses, but device complexity increases requiring reset mechanisms
Solution Approach 1:
By segmenting the device into reusable housing and replaceable cartridge, the complexity of the reset mechanism is minimized. The housing contains pre-integrated reset features (protrusions aligning with slots, spring compression mechanisms) that automatically reset when the cartridge is removed and reinstalled, avoiding the need for complex manual reset procedures.
Solution Approach 2:
The device performs self-resetting through the interaction between the housing protrusions and cartridge slots. When the cartridge is removed and reinserted, the protrusions automatically align with the slots and trigger the spring to reset, eliminating the need for external intervention or complex reset mechanisms operated by the user.
3Reliability
If the entire auto-injector mechanism is replaced after single use, then reliability is maintained, but waste increases and cost increases
Solution Approach 1:
The device is segmented into a durable reusable housing and a disposable cartridge. Only the cartridge containing the medicament is discarded after single use, while the housing with the actuation mechanism is reused multiple times. This reduces material waste significantly compared to discarding the entire device, while reliability is maintained through the sealed, single-use nature of the cartridges.
Solution Approach 2:
The design enables selective discarding of only the consumable cartridge while recovering and reusing the housing and actuation mechanism. This recovers valuable materials and components for multiple uses, reducing waste and environmental impact while maintaining reliability through dedicated single-use cartridges that ensure proper dosing.
4Productivity
If a reusable design with reset capability is used, then productivity increases through multiple doses, but ease of operation decreases due to reset procedures
Solution Approach 1:
The reset function is designed as a self-service operation that occurs automatically when the cartridge is removed and reinserted. The protrusions on the housing align with slots on the cartridge, and this mechanical interaction automatically triggers the spring to reset and the needle to return to its initial position, eliminating the need for complex manual reset procedures and maintaining ease of operation.
Solution Approach 2:
The segmentation into reusable housing and replaceable cartridge simplifies the reset operation to basic cartridge removal and reinstallation. The housing contains all necessary reset mechanisms (spring, protrusions, slots) that automatically execute the reset function during the simple act of cartridge replacement, making the operation intuitive and easy for users to perform.
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 design reduces costs by allowing multiple uses of the auto-injector, increasing accessibility and usability by enabling the administration of multiple doses without the need for frequent replacements, addressing the concern of affordability and usability.
Implementation Method 1
The actuation assembly can at least partially internally house a compression spring, a spring compression member, a needle, and a firing member. The spring compression member can be configured to couple with the actuation assembly and contact the compression spring
Implementation Method 2
While in the unfired position, the compression spring can be restricted into a compressed state, whereby the compression spring in the compressed state can be operable to position the needle within the central cavity of the housing. While in the fired position, the compression spring can be unrestricted into an expanded state, whereby the compression spring in the expanded state can be operable to transition the needle outward from the central cavity of the housing
Data Source
AI summary
An auto-injector includes a housing and an actuation assembly. The housing includes a central cavity, opposing ends, and a longitudinal axis defined spanning between the opposing ends. The actuation assembly is shaped to position within the central cavity. The actuation assembly is configured to at least partially internally house a spring, a spring compression member, a needle operable to eject a fluid therefrom, a firing member selectively translatable between an unfired position and a fired position, and a firing initiation member. While in the unfired position, the needle is held within the central cavity of the housing. While in the fired position, the needle is extended outward from the central cavity of the housing.