Autoinjector Dual-Spring Mechanism for Compact Design
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Solution Overview
Problem
There is a need for compact autoinjectors that are easy to manufacture, assemble, and use, while also reducing costs and environmental impact, as existing autoinjectors are often cumbersome and complex.
Innovation Solution
The autoinjector design features a cylindrical housing with a slideable syringe and a dual-spring mechanism, where the first spring drives the syringe forward to penetrate the skin and the second spring expels the medicament, with optional magnetic enhancements for improved functionality and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing autoinjector designs are used, then injection function is achieved, but device complexity and size increase
Solution Approach 1:
The autoinjector is divided into distinct functional modules: a trigger assembly with first and second springs for penetration and injection functions, a syringe assembly with piston and needle, and a housing with magnetic latch mechanism. This segmentation allows each component to be optimized independently while maintaining overall reliability.
Solution Approach 2:
The syringe assembly is nested within the housing, with the piston contained within the syringe barrel. The magnetic latch mechanism is integrated into the housing structure, and the trigger button is positioned within the rear portion of the housing. This nested arrangement reduces overall device complexity while preserving all injection functions.
2Volume of moving object
If compact design is implemented, then portability improves, but manufacturing and assembly complexity increases
Solution Approach 1:
The first spring serves dual purposes: it provides the force for needle penetration and also drives the syringe forward for medicament injection. The magnetic latch mechanism serves both as a safety feature to prevent accidental activation and as a mechanism to maintain device compactness. This multi-functionality reduces the number of separate components needed, simplifying manufacturing and assembly.
Solution Approach 2:
The penetration and injection functions are combined into a single trigger action that releases both springs simultaneously. The magnetic latch is integrated with the housing structure rather than being a separate assembly. This merging of functions and components reduces the number of parts, making the device more compact and easier to manufacture.
3Force
If dual-spring mechanism is used, then injection force is improved, but device complexity increases
Solution Approach 1:
The force generation is segmented into two distinct spring mechanisms: the first spring for penetration force and the second spring for injection force. This segmentation allows each spring to be optimized for its specific function while keeping the overall mechanism relatively simple through clear functional separation.
Solution Approach 2:
The first spring performs a dual function by providing both penetration force when the needle enters the skin and continuation force for driving the syringe forward. The second spring then takes over to provide the controlled injection force. This multi-functional approach maximizes injection force while minimizing the number of active components.
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
This design allows for a compact, user-friendly, and cost-effective autoinjector that efficiently delivers doses with reduced manufacturing and environmental costs, while ensuring safe operation and confirmation of injection completion.
Implementation Method 1
a first compression spring which stores and releases power as to drive the syringe to extend the needle to penetrate the skin
Implementation Method 2
a second compression spring which stores and releases power as to drive the piston to express a dose
Implementation Method 3
The plunger is retained in the cocked position by a magnetic latch mechanism
Data Source
Figure 1
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Figure 3
AI summary
An autoinjector comprises a housing (10) to receive a syringe (14), and a drive mechanism comprising first and second springs (30, 32) operating in tandem via an intermediate member (34), on a plunger (42). The plunger is retained in a locked position by a trigger. Release of the trigger causes the first spring to advance the syringe to an arrest point whereafter the second spring extends within the syringe to expel a dose.