Adjustable Dose Injector Volume Control Mechanism
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Solution Overview
Problem
Existing injection devices lack the ability to deliver medicaments in adjustable doses, often requiring the entire loaded dosage to be injected at once, which can be inefficient and inconvenient for patients.
Innovation Solution
An injector with a volume-control mechanism that allows for the selection of a fraction of the medicament to be injected, utilizing a threaded ram biased by an energy source and a stopping member with adjustable position, enabling precise control over the dose delivered through a rotating cap and tracks within the injector's housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the entire loaded dosage is injected at once, then the injection process is simple and quick, but the medicament cannot be used in adjustable doses leading to waste and inefficiency
Solution Approach 1:
The injector incorporates a volume control mechanism with a movable stop that can be adjusted along the barrel to dynamically change the injection volume. This allows the user to select different dosages (e.g., full dose, half dose, quarter dose) by positioning the stop at different locations, transforming a static single-dose device into a dynamic multi-dose system that adapts to different treatment needs.
Solution Approach 2:
The injection volume is segmented into multiple selectable portions through the volume control mechanism. The stop divides the medicament column into an injected portion (between the plunger and stop) and a retained portion (between the stop and needle tip). This segmentation enables precise control over the injected dose while preserving the remaining medicament for subsequent injections.
2Device complexity
If the injector is designed for single use, then the device structure is simple, but refilling is required for multiple injections increasing complexity and time
Solution Approach 1:
The injector is pre-filled with a large volume of medicament (e.g., 3 mL) that exceeds the typical single injection dose. The volume control mechanism is pre-configured with adjustment marks indicating different dose options. This preliminary preparation eliminates the need for refilling during multiple injections, as users can simply adjust the stop position between injections.
Solution Approach 2:
Instead of discarding the remaining medicament after each injection (as in single-use devices), the injector recovers and preserves the unused portion by positioning the stop to retain a specific volume in the barrel. This allows the same medicament supply to be used for multiple injections at different dosages, maximizing resource utilization.
3Measurement precision
If a volume control mechanism is added to enable adjustable dosing, then dosing precision is improved, but the device complexity increases
Solution Approach 1:
The volume control function is extracted as a separate, simple component (the stop with lateral members) rather than being integrated into the main injection mechanism. The stop can be independently adjusted and locked, separating the dosing control function from the injection delivery function. This modular approach adds precision without significantly complicating the overall device structure.
Solution Approach 2:
The volume control mechanism uses simple, inexpensive components such as a plastic stop with lateral members that slide in tracks, rather than complex mechanical or electronic systems. The design prioritizes functional simplicity and manufacturability over high precision engineering, achieving adequate dosing control through basic geometric constraints.
4Adaptability or versatility
If the stopping member is made adjustable along the longitudinal axis, then volume selection flexibility is improved, but the mechanism becomes more complex
Solution Approach 1:
The stop is nested within the injector barrel, with its lateral members sliding within tracks that are integral to or integrated with the barrel structure. The adjustment mechanism is contained within the existing device envelope, requiring no additional external components or space. This nested arrangement provides adjustability while maintaining a compact, integrated design.
Solution Approach 2:
The adjustable stop serves multiple functions: it defines the injection volume, acts as a visual reference (with adjustment marks visible through the window), and can be locked in position during injection. The same component provides both dosing control and injection initiation functions, reducing the need for separate mechanisms.
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
Enables users to control and adjust the dose of medicament delivered, allowing for either single-use or multiple injections with precision, improving convenience and efficiency by allowing partial use of the medicament without the need for refilling.
Implementation Method 1
The energy source is preferably a spring
Implementation Method 2
The volume-control mechanism preferably includes a threaded ram that is biased by an energy source against a plunger and configured for rotating about a longitudinal axis of the injector
Data Source
AI summary
An injector for injecting a medicament in a patient. The injector includes a container comprising a fluid chamber containing a first volume of a medicament, and an injection conduit associated with the fluid chamber for defining a fluid pathway therefrom to inject the medicament from the fluid chamber through the injection conduit to an injection location. The injector also includes a firing mechanism associated with the fluid chamber for expelling the medicament from the fluid chamber through the injection conduit, arid a volume-control mechanism operable to control a fraction of the first volume of medicament that is injected when the firing mechanism is actuated to inject the medicament.