Medicament Delivery Device Cap Inter-locking Mechanism

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Solution Overview

Problem

Existing medicament delivery devices are unreliable and prone to unintentional actuation, and they often require unnecessary steps, such as removing a locking mechanism after mixing is finished, which can be disadvantageous, especially in emergency situations, and may cause medicament degradation due to reaction with delivery member materials.

Innovation Solution

A medicament delivery device with a cap inter-locking mechanism that keeps the needle preassembled without initial penetration, featuring a tubular housing, actuator means, a medicament container holder, and a cap inter-locking member that is axially slidable but rotationally locked, ensuring the device cannot be actuated unintentionally and allowing pre-tensioned states to maintain safety and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the device uses a pre-assembled needle with the container, then the device complexity is reduced and productivity is improved, but the needle may protrude into the container causing medicament degradation

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

Solution Approach 1:

The delivery member is segmented into a needle portion and a hub portion that can be pre-assembled. The needle can be inserted into the container while the hub remains outside, allowing pre-assembly without full insertion. This segmentation enables the needle to be positioned correctly without the entire delivery member protruding into the container, thus preventing medicament degradation while maintaining assembly efficiency.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the device uses manual pressing activation, then the ease of operation is improved, but the reliability deteriorates due to unintentional actuation

Engineering Contradiction:
Improveactivation simplicityVSAvoidunintentional actuation prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A resilient member is pre-loaded in a biased state that opposes the activation direction. The delivery member is held in a retracted position by this pre-loaded resilient force, creating a preliminary counter-action that prevents unintentional activation. The user must deliberately overcome this resilient force to activate the device, ensuring intentional use while maintaining simple manual operation.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The resilient member is pre-tensioned or pre-compressed during device assembly, storing energy that will be released upon activation. This preliminary action prepares the device for controlled activation while maintaining safety during storage and transport. The pre-loaded spring provides a ready-to-activate state that requires deliberate user action to trigger, preventing accidental deployment.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the device includes a locking mechanism, then the reliability is improved by preventing unintentional actuation, but the ease of operation worsens due to additional removal steps

Engineering Contradiction:
Improveactivation controlVSAvoidnumber of steps
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking function is merged with the activation mechanism itself. The resilient member serves both as the activation force and as the locking mechanism. When the user presses the delivery member, they simultaneously overcome the resilient force (activation) and release the lock. This merging eliminates separate locking and activation steps, maintaining reliability while improving ease of operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resilient member automatically locks the delivery member in the retracted position during storage and transport without user intervention. Upon activation, the same resilient member automatically releases the lock as it is compressed by user pressure. This self-service locking and unlocking mechanism eliminates the need for separate manual locking or unlocking steps, maintaining safety while simplifying operation.

Inventive Principle:
Principle #25Self-service

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 cap inter-locking mechanism prevents unintentional actuation and maintains the needle outside the medicament container until activation, ensuring safety and reliability, while allowing pre-assembled devices to avoid medicament degradation and reducing the number of steps required for use.

Implementation Method 1

a first resilient member arranged at the distal end of the actuator means, between an annular ledge of the tubular housing and an annular ledge of the actuator means

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Data Source

PatentEP2555819B1Medicament delivery device
Publication Date: 2019.06.26 SHL MEDICAL AG
  • EP2555819B1 patent drawingFigure 1A
  • EP2555819B1 patent drawingFigure 1B
  • EP2555819B1 patent drawingFigure 2A~2B

AI summary

Provided is a medicament delivery device (100) comprising a tubular housing (110), having a proximal end (111) and an opposite distal end (112), an actuator means (119, 120), slidably and coaxially arranged inside the tubular housing (110) wherein is provided an inter-locking mechanism (119, 413) between the a cap (410) and the housing (110), enabling the cap (410) to freely spin, i.e. it is impossible to open the cap (410), until the medicament delivery device (100) has been properly activated by an activator means (160).