Drug Delivery Device Needle Shield Locking Mechanism

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Solution Overview

Problem

Current drug delivery devices face challenges in ensuring accurate needle insertion depth and safety during administration, as existing mechanisms may not effectively prevent syringe deflection or provide clear feedback on correct insertion.

Innovation Solution

A drug delivery device with flexible arms and a support member system that locks the syringe in a defined gauge position, using a needle cover sleeve to move the support member to a proximal position, preventing deflection and providing audible feedback for correct insertion depth, and incorporating a hook and latch mechanism for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the support member is in the distal position to allow easy insertion of the syringe with protective needle sheath, then the flexible arms can deflect outward to accommodate the sheath, but the syringe cannot be securely locked in position and may deflect during forceful insertion

Engineering Contradiction:
Improveease of insertionVSAvoidposition stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The support member is designed to be movable between a distal position (allowing flexible arm deflection during insertion) and a proximal position (locking the syringe in place). This dynamic reconfiguration allows the system to adapt its stiffness characteristics based on the operational phase, resolving the contradiction between ease of insertion and position stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the mechanical parameter of the flexible arms by moving the support member between positions. In the distal position, the arms are allowed to deflect (higher flexibility); in the proximal position, the arms are constrained (lower flexibility), thereby changing the overall mechanical compliance of the assembly to match different operational requirements.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the support member constrains the flexible arms to prevent deflection and ensure accurate needle insertion depth, then the syringe position is stable, but the flexible arms cannot deflect outward to accommodate the protective needle sheath during insertion

Engineering Contradiction:
Improveneedle insertion depth accuracyVSAvoidease of insertion
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The support member's position is dynamically changed from distal to proximal at the appropriate moment during the insertion process. This allows the system to first accommodate the protective sheath with flexible arms, then lock the syringe in the correct position with the arms constrained, achieving both ease of insertion and precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flexible arms are allowed to deflect outward in advance to accommodate the protective needle sheath during insertion. After the sheath is in place, the support member is moved to the proximal position to constrain the arms and establish the precise needle insertion depth, ensuring that the preliminary accommodation action does not compromise the final precision requirement.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the protrusions on the flexible arms continuously support the syringe neck, then the syringe position is well-defined, but the protective needle sheath cannot pass through the protrusions during insertion

Engineering Contradiction:
Improvesyringe position definitionVSAvoidease of insertion
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The support member's position is dynamically adjusted: in the distal position, the protrusions are moved away from the syringe neck to allow the protective sheath to pass through; in the proximal position, the protrusions engage the neck to define the syringe position. This dynamic repositioning resolves the contradiction between allowing passage and providing support.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If the flexible arms are made more rigid to prevent deflection and ensure accurate needle insertion, then the needle insertion depth is more consistent, but the arms cannot deflect outward to accommodate the protective needle sheath and may be damaged during insertion

Engineering Contradiction:
Improveneedle insertion depth consistencyVSAvoidsyringe damage risk
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system dynamically changes the rigidity of the flexible arms by moving the support member between distal and proximal positions. During insertion, the arms are flexible to accommodate the sheath; after insertion, the arms become rigid to ensure consistent needle insertion depth, thereby avoiding damage while achieving precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The movable support member acts as a cushioning mechanism that is positioned to allow deflection during the insertion phase, protecting the syringe from damage. After insertion is complete, the support member moves to constrain the arms, providing the rigidity needed for consistent needle insertion depth without having compromised the syringe during the vulnerable insertion phase.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

Ensures consistent and accurate needle insertion depth, reduces the risk of syringe damage, and provides user feedback for safe and effective medicament delivery.

Implementation Method 1

the protective needle sheath abuts the protrusions on the flexible arms and deflects them outwards so that the protective needle sheath may pass through the protrusions. After having passed the protective needle sheath the protrusions are allowed to relax into a gap between the protective needle sheath and the syringe

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

If the support member is moved into the proximal position, the flexible arms cannot deflect so a force exerted on the syringe, e.g. a force from a plunger rod acting on a stopper within the syringe, does not result in deflection of the flexible arms and movement of the syringe. Instead, this force is resolved within the inner body

Methodology Applied
Scientific EffectMechanical constraint:

Implementation Method 3

when the needle cover sleeve moves from the distal position towards the proximal position, the needle cover sleeve engages and moves the support member from the distal position to the proximal position

Methodology Applied
Scientific EffectMechanical engagement: Mechanical Fastener

Implementation Method 4

incorporating a hook and latch mechanism for secure engagement

Methodology Applied
Scientific EffectMechanical Fastening: Mechanical Fastener

Implementation Method 5

provides audible feedback for correct insertion depth

Methodology Applied
Scientific EffectAudible feedback: Sound

Data Source

PatentEP3484556B1Drug delivery device with controlled needle shield and cover sleeve
Publication Date: 2023.07.05 SANOFI AVENTIS DEUT GMBH
  • EP3484556B1 patent drawingFigure 1
  • EP3484556B1 patent drawingFigure 2
  • EP3484556B1 patent drawingFigure 3

AI summary

The present disclosure relates to a drug delivery device (1), comprising: - an inner body (2.1) adapted to receive a pre-filled syringe (3) with an injection needle (4), - one or more flexible arms (5) on the inner body (2.1) extending in a distal direction (D), the flexible arms (5) having respective inwardly directed protrusions (6) adapted to engage a neck (7) of the syringe (3), - one or more support members (11) slidably arranged to operatively outwardly support the flexible arms (5), wherein, when the support member (11) is in a distal position (S1), it does not support the flexible arms (5), wherein, when the support member (11) is in a proximal position (S2), the support member(11)supports the flexible arms (5) and prevents them from being outwardly deflected.