Spring-Assisted Needle Cap for Medicament Injection Device

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Solution Overview

Problem

Medicament injection devices, particularly those using cartridges, pose challenges for patients with limited dexterity or coordination due to the additional step required for needle attachment, which can compromise sterility and ease of use.

Innovation Solution

A medicament injection device featuring a main body with a medicament cartridge holder and a needle holder that is axially movable, activated by a rotatable cap with pre-stressed springs, allowing automatic needle insertion into the cartridge upon cap rotation, eliminating the need for direct needle handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cartridge is used instead of a syringe, then handling and storage advantages are provided, but an additional needle attachment step is required that complicates operation for patients with limited dexterity

Engineering Contradiction:
Improvehandling and storageVSAvoidneedle attachment step
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent combines the needle holder and cartridge holder into a single integrated assembly where the needle is pre-mounted on the cartridge. This merging eliminates the separate needle attachment step while maintaining the cartridge's handling and storage advantages, directly resolving the contradiction between ease of manufacture and ease of operation.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the needle is kept separate from the medicament until injection, then sterility is maintained, but an additional attachment step is required that reduces ease of use

Engineering Contradiction:
Improvesterility maintenanceVSAvoidattachment step
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The needle is pre-attached to the cartridge in a sterile manner during manufacturing, and the entire assembly is then sterilized together. This preliminary action maintains sterility while eliminating the need for a separate attachment step at the point of use, resolving the contradiction between reliability and ease of operation.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If a double-ended needle is used with a cartridge, then injection is enabled, but patients with poor coordination or lost sensation find the attachment step problematic

Engineering Contradiction:
Improveinjection capabilityVSAvoidattachment step for patients with limited dexterity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The device is designed so that the needle is already attached to the cartridge, making the device self-sufficient and eliminating the need for the patient to perform the attachment step. This self-service design maintains injection capability while removing the operation step that is problematic for patients with limited dexterity or coordination.

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 device ensures the needle remains separate from the medicament until injection, simplifying the process for users and maintaining sterility, thereby improving usability and safety for patients with dexterity issues.

Implementation Method 1

the cap comprises a first pre-stressed spring coupled to the needle holder, and at least one activation element and wherein the first pre-stressed spring is attached at a proximal end thereof to a plate, and wherein rotation of the cap from a first position in which the activation element is in blocking engagement with the plate to a second position in which the activation element is out of blocking engagement with the plate causes the plate and the first pre-stressed spring to be released, thereby causing the plate to push the needle holder towards a proximal end of the device

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The device further comprises a second pre-stressed spring arranged to be released in response to rotation of the cap subsequent to release of the first pre-stressed spring, thereby causing the cap to move axially away from the main body in a distal direction.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3380165B1Medicament injection device with spring-assisted protective needle cap
Publication Date: 2023.04.19 SANOFI AVENTIS DEUT GMBH
  • EP3380165B1 patent drawingFigure 1A~1B
  • EP3380165B1 patent drawingFigure 2A~3B
  • EP3380165B1 patent drawingFigure 4A~5B

AI summary

A medicament injection device comprising: a main body; a medicament cartridge holder fixed with respect to the main body, wherein themedicament cartridge holder is configured to hold a medicament cartridge; a needle carrier carrying a needle, wherein the needle carrier is axially movable with respect to the main body; and a rotatable cap at a distal end of the device, wherein the cap comprises a first pre-stressed spring coupled to the needle carrier, wherein the cap is arranged so that rotational movement thereof causes release of the first pre-stressed spring thereby causing the needle carrier to move axially towards a proximal end of the device.