Auto-Injector Needle Guard and Ram Mechanism
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Solution Overview
Problem
Auto-injectors for medicaments have complex designs requiring numerous parts and precise tolerances, leading to complicated assembly and high manufacturing costs.
Innovation Solution
A simplified auto-injection device with a reduced number of components, including a housing, syringe, needle guard, ram, and springs, which interact to expose and protect the needle without additional components, allowing for automatic injection and needle protection with fewer assembly steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional auto-injector designs are used, then reliable automatic injection and needle protection are achieved, but device complexity and manufacturing cost increase due to numerous components and precise tolerance requirements
Solution Approach 1:
The patent combines multiple functions into fewer components. The needle guard serves both as a protective cover and as a component that interacts with the retaining arm and lock arm mechanisms. The ram integrates the firing mechanism with the needle guard actuation, eliminating the need for separate components for each function while maintaining reliable automatic injection and needle protection.
Solution Approach 2:
Components are designed to perform multiple functions. The needle guard not only protects the needle during storage but also acts as a trigger mechanism when pressed by the user. The retaining arm and lock arm work together to both prevent premature firing and ensure proper sequencing of operations, reducing the total component count while maintaining reliability.
2Ease of operation
If traditional auto-injector designs with numerous components are used, then safe and convenient medicament delivery is achieved, but manufacturing cost and assembly complexity increase
Solution Approach 1:
By merging the needle guard, retaining arm, and lock arm into an integrated system with fewer discrete components, the patent reduces assembly steps and manufacturing complexity. The simplified design maintains safe and convenient operation through the coordinated interaction of these combined components, lowering production costs while preserving user safety and convenience.
Solution Approach 2:
The device is designed to automatically perform sequencing of operations without requiring multiple separate components or complex control mechanisms. The spring-loaded ram and interacting arms create a self-actuating system that automatically progresses through the injection sequence when triggered, reducing the need for additional control components and simplifying manufacturing.
3Device complexity
If a simplified design with fewer components is used, then manufacturing complexity and cost are reduced, but maintaining reliable needle protection and automatic injection becomes more difficult
Solution Approach 1:
The retaining arm is pre-positioned to block the ram's longitudinal path before injection, ensuring the device cannot be accidentally activated. The spring-loaded mechanism is pre-tensioned to automatically drive the ram forward when the retaining arm is released, ensuring reliable automatic injection without requiring additional actuators or control components.
Solution Approach 2:
The lock arm is designed to engage with the needle guard's longitudinal path in advance, preventing premature retraction of the needle guard after injection. This pre-positioned locking mechanism ensures reliable needle protection is maintained throughout the injection process and until proper disposal, without requiring complex control systems.
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 device simplifies assembly, reduces manufacturing complexity, and allows for a greater range of acceptable dimensional tolerances, making it more cost-effective and user-friendly while maintaining safe and convenient medicament delivery.
Implementation Method 1
a needle guard slideably coupled to the housing and spring biased in a distal direction relative to the housing by a return spring
Implementation Method 2
a ram slideably coupled to the housing and spring biased in the distal direction relative to the housing by a main spring
Data Source
AI summary
An injection device for injecting medicament in a patient includes a syringe coupled to a housing and radially retained by a retaining rib. A needle guard is slideably coupled to the housing and spring biased in a distal direction by a return spring. A ram is slideably coupled to the housing and spring biased in the distal direction by a main spring. An initial position is defined by a retaining arm being disposed in the longitudinal path of the ram preventing firing. A released position is defined by the retaining arm being clear from the longitudinal path of the ram allowing the ram to extend distally. A locked position is defined by the retaining arm being disposed in the longitudinal path of the ram and a lock arm of the ram being disposed in the longitudinal path of the needle guard preventing the needle guard from being retracted.