Medical Injector Knob Mechanism for Automated Reconstitution

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Solution Overview

Problem

Existing autoreconstitution devices for mixing drug components require substantial manual force to activate and can be difficult to operate, with components sometimes getting stuck, rendering the injector inoperable.

Innovation Solution

A medical injector with a body containing a reservoir for mixable components, a plunger, and a rotatable knob system that, when turned, activates a spring to distally move a sleeve and stopper, facilitating the mixing of components without manual force, and includes a releasable retainer and cooperating elements to allow controlled mixing and dose setting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a trigger-activated automated reconstitution mechanism is used, then automated mixing is achieved, but substantial force is required to activate and components may get stuck

Engineering Contradiction:

Improveautomated reconstitutionVSAvoidactivation force

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The patent replaces the trigger-activated mechanical system with a knob-based rotational mechanism. The knob rotates to engage a cam mechanism that converts rotational motion into linear displacement of the plunger, eliminating the need for substantial activation force while maintaining automated reconstitution functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a spring mechanism that provides dynamic force assistance during the reconstitution process. The spring engages as the knob rotates, automatically pushing the plunger to mix the components, thereby reducing the operational force required from the user.

Inventive Principle:

Principle #15Dynamics

2Extent of automation

If a trigger-activated mechanism is used, then automated reconstitution is achieved, but components occasionally get stuck rendering the injector inoperable

Engineering Contradiction:

Improveautomated reconstitutionVSAvoidcomponent stuck

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent replaces the trigger mechanism with a knob-based rotational system that engages a cam mechanism. This substitution eliminates the sticking problem by using a different mechanical approach where rotational motion continuously engages the cam, ensuring smooth plunger movement and reliable reconstitution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring mechanism is pre-loaded to provide continuous force assistance during the reconstitution process. This preliminary preparation of the spring force ensures that components are continuously pushed together, preventing them from getting stuck during operation.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If a bypass channel is formed in the barrel for mixing, then mixing function is provided, but the device must be specifically configured for mixing

Engineering Contradiction:

Improvemixing functionVSAvoidspecific configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the injector with a universal mixing mechanism where the plunger and cam system can mix components of varying viscosities and densities. The rotational knob mechanism provides a universal interface that works with different drug formulations without requiring device reconfiguration, achieving mixing functionality while maintaining device simplicity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effortless autoreconstitution of drug components by turning a knob, reducing the risk of mechanical failure and allowing precise dose adjustment, making the device more user-friendly and reliable.

Implementation Method 1

A spring is also provided for urging the sleeve distally

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentEP2328639B1Medical injector with dose knob activation for automated reconstitution

Publication Date: 2017.02.15 BECTON DICKINSON & CO

AI summary

A medical injector is provided herein having a body and a reservoir disposed in the body, the reservoir including at icast first and second rrπxable components. At least one stopper is associated with the reservoir where dista! advancement of the stopper over a predetermined distance causes mixing of the mixable components. A plunger is disposed in the body, along with a knob stem and a knob fixed to the knob stem so as to be rotatabie therewith. A sleeve is telescopingly disposed over the knob stem, wherein the knob stem and the sleeve have cooperating elements formed thereon which selectively permit rotation of the knob stem to be transmitted to the sleeve so that the knob stem and the sleeve may rotate together. A spring is also provided for urging the sleeve distally. A releasabie retainer releasably retains the sleeve against force of the spring. Rotation of the knob releases the sleeve and allows the spring to displace the sleeve distally. Distal movement of the sleeve causes distal movement of the plunger which causes distal movement of the stopper thus causing mixing of the mixable components. Advantageously, with the subject invention, a medical injector may be provided where autoreconstitution can be achieved by the turning of a knob.