Medicament Delivery Device Spring Mixing Mechanism

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Solution Overview

Problem

Existing medicament delivery devices for dual-chamber containers face issues such as premature activation, high mixing forces degrading medicaments, reliance on batteries prone to malfunctions, and complex user interfaces, particularly in emergency situations, where safety and dose accuracy are compromised.

Innovation Solution

A medicament delivery device with a movable housing system that includes a drive force mechanism held by a holding member, an actuation member that biases to release the mechanism only after user-initiated activation, and a plunger rod mechanism with engagement means to ensure controlled medicament mixing and injection, preventing accidental activation and providing intuitive operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automatic mixing is performed by springs upon activation, then mixing efficiency is improved, but mixing force becomes too high at the beginning causing medicament degradation

Engineering Contradiction:
Improvemixing efficiencyVSAvoidmedicament degradation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The spring mechanism is designed to provide varying force over time through periodic action. The spring gradually releases its stored energy, providing initial high force to quickly mix the medicament and diluent, then progressively reducing the force as mixing completes, thereby preventing degradation from excessive force while maintaining mixing efficiency

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The spring constant and pre-compression parameters are specifically selected to change the force profile during mixing. By adjusting these parameters, the system transforms the force application from constant high force to a decreasing force profile that adapts to the mixing process stages, resolving the contradiction between mixing speed and medicament protection

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If electronically controlled mixing and injection are used, then dosing precision is improved, but device complexity and manufacturing cost increase due to batteries and electronic sensitivity

Engineering Contradiction:
Improvedosing precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention replaces electronic control systems with a purely mechanical spring-based control system. The spring mechanism mechanically controls the timing and force of mixing and injection operations, eliminating the need for batteries, electronic circuits, and associated complexity while maintaining precise dosing through mechanical design

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring mechanism is pre-loaded during manufacturing to automatically control the mixing and injection process without external power or control systems. The device serves itself through the stored mechanical energy in the spring, which automatically regulates the sequence and precision of operations, eliminating electronic dependencies

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If manual mixing with eye observation is used, then medicament degradation is minimized through gentle mixing, but ease of operation deteriorates requiring user training and attention

Engineering Contradiction:
Improvemedicament degradationVSAvoidease of operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The spring mechanism automatically performs the mixing action with controlled force, eliminating the need for user observation and manual control. The device self-regulates the mixing process to apply gentle force throughout, protecting the medicament while requiring minimal user intervention beyond initial activation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring acts as an intermediary between the user's activation action and the mixing process. It translates a simple user input into a controlled, gentle mixing action that would be difficult for a user to achieve manually, thereby protecting the medicament while simplifying operation

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If locking means are actively removed after mixing, then safety is improved preventing premature activation, but ease of operation worsens as users may not intuitively know to remove locking means

Engineering Contradiction:
ImprovesafetyVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism transitions from a static locked state to an automatic unlocked state through dynamic interaction with the spring mechanism. After mixing, the spring's movement automatically releases the locking means, eliminating the need for user action to disengage the lock while maintaining safety during the critical mixing phase

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system provides mechanical feedback through the spring mechanism that automatically triggers the unlocking action after mixing completion. The spring's position and force provide inherent feedback about the mixing state, automatically controlling the locking/unlocking sequence without requiring user knowledge or decision-making

Inventive Principle:
Principle #23Feedback

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 ensures safe and reliable medicament delivery by preventing accidental activation, minimizing medicament degradation, and offering a user-friendly interface with tactile feedback for complete injection confirmation, while maintaining cost-effectiveness and simplicity in design.

Implementation Method 1

said actuation member is resiliently connected to said distal housing part such that said actuation member is always recoiled after being biased regardless of whether the actuation mechanism is released

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The drive force mechanism comprises a plunger rod, a drive force spring and a drive member

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2611481B1Medicament delivery device
Publication Date: 2018.12.12 SHL GRP AB
  • EP2611481B1 patent drawingFigure 1
  • EP2611481B1 patent drawingFigure 2
  • EP2611481B1 patent drawingFigure 3

AI summary

The present invention relates to a medicament delivery device comprising a generally elongated housing, which housing comprises a proximal housing part and a distal housing part arranged and mounted to be movable relative each other; a drive force mechanism accommodated in said distal housing part and being slidably arranged in relation to the distal housing part; a container filled with medicament arranged within said proximal housing part; a holding member operably connected to said drive force mechanism for holding said drive force mechanism in a loaded state, wherein said holding member is arranged to be axially moved in relation to the distal housing part a predetermined distance towards a distal end of the device by the proximal housing part when said housing parts are moved towards each other; and an actuation member configured to be biased in relation to the distal housing part from a non- operating position in which the actuation member partially protrudes from the distal housing part to an operating position in which the actuation member is confined within the distal housing, and wherein said actuation member is operably connected to said drive force mechanism for releasing the drive force mechanism from its loaded state; wherein said actuation member is resiliently connected to the distal housing part such that said actuation member is always recoiled after being biased regardless of whether the actuation mechanism is released; and wherein said drive force mechanism is configured to be released from its loaded state only after the holding member is axially moved in relation to the distal housing part and the actuation member is biased from the non-operating to the operating position.