Medicament Delivery Locking Mechanism for Defined Dose Activation

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Solution Overview

Problem

Existing medicament delivery devices face issues with complex mechanical components leading to frictional problems and increased manufacturing costs, along with a lack of well-defined activation points during use.

Innovation Solution

A medicament delivery device incorporating a locking mechanism with a plunger rod, actuator, and actuator sleeve, featuring a groove and holding ledge for direct engagement, and a locking ring with splines for rotational stability, providing a well-defined activation point and preventing axial retraction of the delivery member guard.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large number of mechanical components are used to provide automatic functions and features, then the functionality and ease of use are improved, but the device complexity and manufacturing costs increase

Engineering Contradiction:
Improveautomatic functionsVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into fewer components. The actuator serves both as a manual activation mechanism and as part of the automatic dose delivery system. The locking mechanism integrates both manual engagement and automatic dose completion detection functions, reducing the need for separate components for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator is designed to serve multiple purposes: it can be manually activated by the user to initiate dose delivery, and it also participates in the automatic activation sequence when the device is properly engaged with the dose delivery site. The locking mechanism similarly provides both manual engagement capability and automatic dose completion detection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a large number of mechanical components are used to provide automatic functions and features, then the functionality and ease of use are improved, but the frictional forces during device use increase

Engineering Contradiction:
Improveautomatic functionsVSAvoidfrictional forces
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

By merging functions into fewer components, the patent reduces the total number of contact interfaces between moving parts. The actuator and locking mechanism are designed as integrated assemblies that minimize the number of separate mechanical interactions required to achieve the same functionality, thereby reducing cumulative frictional forces.

Inventive Principle:
Principle #5Merging (Combining)

3Extent of automation

If indirect engagement between components is used to form a complex mechanism, then the automatic functions are achieved, but the activation points become less well-defined

Engineering Contradiction:
Improveautomatic dose deliveryVSAvoidactivation point definition
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent extracts and eliminates unnecessary intermediate components from the activation mechanism. The actuator is directly connected to the plunger rod through a simplified linkage, and the locking mechanism directly engages with the actuator, creating well-defined activation points without complex indirect engagement chains.

Inventive Principle:
Principle #2Taking out (Extraction)

4Object-affected harmful factors

If the delivery member guard can retract axially for automatic covering, then the safety and automatic features are improved, but the component complexity and assembly difficulty increase

Engineering Contradiction:
Improveneedle exposure protectionVSAvoidassembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The locking mechanism is designed to simultaneously achieve two functions: it locks the actuator in place during manual engagement, and it also serves as the engagement point for the delivery member guard. When the locking mechanism engages or disengages, it directly controls the guard's position, eliminating the need for separate control mechanisms and reducing assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 solution minimizes frictional forces and reduces component complexity, ensuring a well-defined activation point for dose delivery and preventing accidental needle exposure, while maintaining device functionality and safety.

Implementation Method 1

a spring arranged to exert a force on the plunger rod in a distal direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a locking mechanism to generate an end-of-dose delivery signal and also to prevent axial retraction of a delivery member guard

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4121143B1Medicament delivery device with a locking mechanism
Publication Date: 2026.02.18 SHL MEDICAL AG
  • EP4121143B1 patent drawingFigure 1
  • EP4121143B1 patent drawingFigure 2
  • EP4121143B1 patent drawingFigure 3

AI summary

A dose delivery mechanism and a medicament delivery device are presented having a housing holding a medicament container and a power unit, where the power unit has a plunger rod, a drive spring, operably arranged to act on the plunger rod and on the medicament container. A locking ring is operatively engaged with an actuator having a holding ledge that can releasably hold the plunger rod with the drive spring in a tensioned state, and with an actuator sleeve to form a lock that prevents axially movement of the actuator after dose delivery. The locking ring also cooperates with the actuator to generate an end-of-dose delivery signal. An activator is directly engaged with the actuator to provide a well-defined activation point.