Needle Guard Rotator Locking for Safe Medicament Delivery

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Solution Overview

Problem

Existing medicament delivery devices lack robust safety mechanisms to prevent accidental activation or contamination of the medicament delivery member before, during, and after use.

Innovation Solution

A safety device with a housing, a medicament delivery member guard, a biasing element, and a rotator that locks the guard in a final position using a protrusion and stop member mechanism to prevent accidental distal movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a safety device is added to prevent accidental activation or contamination, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety device is nested within the existing medicament delivery device structure. The guard member is received within the housing, and the rotator mechanism is integrated into the housing structure. This nesting approach provides safety functionality while minimizing the increase in overall device complexity and size.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The rotator acts as an intermediary mechanism between the guard member and the housing. It provides a controlled interface for locking and unlocking the guard member through interaction with the stop member and guide track, simplifying the overall safety mechanism while ensuring reliable operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a locking mechanism is implemented to prevent accidental movement, then reliability is improved, but ease of operation may worsen

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

Solution Approach 1:

The locking mechanism transitions from a static locked state to a dynamic unlocked state through user action. The rotator can be rotated to engage or disengage the stop member from the guide track, providing controlled accessibility. This dynamic behavior ensures the guard remains locked during storage and transport but can be easily unlocked when needed for medicament delivery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The biasing element automatically pushes the guard member to its default locked position within the housing without requiring user intervention. The system self-regulates the locking state through the interaction of the biasing element, rotator, and guide track, reducing the operational burden on the user while maintaining safety.

Inventive Principle:
Principle #25Self-service

3Reliability

If the guard member is made axially movable to protect the delivery member, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety function is segmented into distinct components: the guard member for physical protection, the rotator for locking control, the stop member for positioning, and the biasing element for automatic positioning. This segmentation allows each component to perform its specific function efficiently while keeping the overall mechanism relatively simple and maintainable.

Inventive Principle:
Principle #1Segmentation

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 effectively locks the medicament delivery member guard in place after use, preventing injury or contamination, and ensuring safe handling of the device.

Implementation Method 1

a biasing element arranged between a distally directed support surface of the medicament delivery member guard and a proximally directed support surface of the housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4161612B1Safety device for a medicament delivery device
Publication Date: 2025.12.03 SHL MEDICAL AG
  • EP4161612B1 patent drawingFigure 1
  • EP4161612B1 patent drawingFigure 2A~2C
  • EP4161612B1 patent drawingFigure 3A~3C

AI summary

A safety device for a medicament delivery device, the safety device comprising: a housing extending in a longitudinal direction from a proximal end to a distal end relative to a longitudinal axis and in a circumferential direction relative to the longitudinal axis; a medicament delivery member guard arranged within the housing and being rotationally fixed and axially movable in relation to the housing along the longitudinal axis between a proximal position and a distal position; a biasing element arranged between a distally directed support surface of the medicament delivery member guard and a proximally directed support surface of the housing; and a rotator arranged within the housing and being rotatable in relation to the housing between an initial unlocked position and a final locked position; wherein the medicament delivery member guard comprises a guide track and a stop member, the guide track comprising an inclined section extending in the circumferential and longitudinal directions for rotating the rotator relative to the medicament delivery member guard during use, and the stop member comprising a surface facing the distal end of the housing; wherein the rotator comprises a protrusion, the protrusion radially extending relative to the longitudinal axis, and the protrusion comprises a stop surface facing the proximal end of the housing; wherein in the initial unlocked position the protrusion is arranged in the guide track; wherein in the final locked position the rotator is rotated relative to the initial unlocked position, with respect to the position of the medicament delivery member guard; and wherein in the final locked position the surface of the stop member of the medicament delivery member guard abuts the stop surface of the protrusion so as to lock the medicament delivery member guard against being moved distally in relation to the housing.