Auto-injector Single Drive Means Needle Retraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current auto-injectors for administering liquid medicaments often require complex mechanisms and multiple springs, making them costly and prone to errors in dose delivery, particularly for users with dexterity issues or elderly patients, who may struggle with manual devices and face discomfort due to injection forces and needle movement.
Innovation Solution
A simplified auto-injector design utilizing a single drive means, such as a compression spring, to insert and retract the needle, with a coupling shroud that decouples from the plunger at a pre-determined position to ensure safe needle retraction and medicament delivery, incorporating a rotating collar for frictional damping to reduce skin pressure and a safety mechanism to prevent premature activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If multiple springs and complex mechanisms are used in auto-injectors, then the device can achieve complete automation of injection functions, but the device complexity increases and cost increases
Solution Approach 1:
The patent combines multiple spring functions into a single compression spring that performs both the injection drive function and the needle retraction function. This merging of functions reduces the number of parts from multiple springs to one, thereby reducing device complexity while maintaining complete automation of injection and retraction operations
Solution Approach 2:
The single compression spring is designed to serve multiple purposes: it provides the driving force for needle insertion, maintains pressure during medicament delivery, and powers the automatic needle retraction. This multi-functional design eliminates the need for separate mechanisms for each function, reducing overall device complexity
2Extent of automation
If multiple springs and complex mechanisms are used in auto-injectors, then the device can achieve complete automation of injection functions, but the manufacturing cost increases
Solution Approach 1:
By merging multiple spring components into a single compression spring, the patent reduces the number of parts that need to be manufactured, assembled, and quality-checked. This simplification directly reduces manufacturing cost while preserving full automation capabilities
Solution Approach 2:
The patent designs the auto-injector as a disposable single-use device with simplified construction. The single spring mechanism is easier and cheaper to manufacture than multi-spring systems, making the disposable device more cost-effective while maintaining automated injection and retraction functions
3Device complexity
If manual devices are used for injections, then the device complexity is low, but the user may deliver an underdose due to improper use
Solution Approach 1:
The auto-injector is designed to perform all injection functions automatically without requiring user intervention during the injection process. The single spring mechanism self-actuates to insert the needle, deliver the medicament, and retract the needle, eliminating user errors that lead to underdosing while keeping the device simple
Solution Approach 2:
The compression spring is pre-loaded and stored in a ready state before use. Upon activation, it automatically executes the complete injection sequence without requiring the user to manually control plunger pressure or timing, ensuring the full prescribed dose is delivered reliably
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 enhances user safety and comfort by reducing injection forces, ensuring complete dose delivery, and providing a cost-effective, single-use device with reliable safety features, suitable for subcutaneous or intramuscular injections.
Implementation Method 1
a single drive means, such as a compression spring
Implementation Method 2
incorporating a rotating collar for frictional damping to reduce skin pressure
Data Source
Figure 1A~2
Figure 3~4B
Figure 5~6B
AI summary
According to the invention, an auto-injector (1) for administering a dose of a liquid medicament (M) comprises - a substantially cylindrical housing (2) arranged to contain a pre-filled syringe (5), - a syringe retainer (4) slidably arranged with respect to the housing (2) that mounts a pre-filled syringe (5), - a coupling shroud (6) slidably arranged within the housing (2) and releasably coupled to the plunger (9) and - a single drive means (8). The proximal translatory movement of the coupling shroud (6) with respect to the housing (2) - translates the syringe retainer (4) to expose the injection needle (12), - depresses the plunger (9) to expel the dose of medicament (M) and - advances a needle shroud (3) to a safe position (PS) to surround the injection needle (12) after the medicament (M) has been at least partially delivered. The coupling shroud (6) is decoupled from the plunger (9) at a pre-determined second position (II) defined by an aperture (2.3) formed into the housing (2).