Rotating Needle-Cover Mechanism for Medicament Injection Completion

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Solution Overview

Problem

Existing medicament delivery devices require multiple actions and lack confirmation of injection completion, increasing the risk of human error and complexity in self-administration.

Innovation Solution

A drive mechanism with a rotator and needle cover that rotates to release a plunger rod, providing audible, tactile, and visual confirmation of injection completion through a guide rod mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotator and needle cover mechanism is used to release the plunger rod, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of operationVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The drive mechanism is segmented into distinct functional components: a rotator for initiating rotation, a needle cover that rotates to release the plunger rod, and a plunger rod spring positioned within a cavity. This segmentation allows each component to perform a specific function independently, simplifying the overall operation while managing complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The plunger rod spring is pre-positioned within the cavity defined by the rotator, and the needle cover is pre-configured to engage the rotator's outer surface. This preliminary arrangement ensures that when the user rotates the needle cover, the plunger rod is automatically released without requiring additional actions, thereby improving ease of operation

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple actions are required for injection, then the reliability of dose delivery is improved, but the ease of operation deteriorates

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

Solution Approach 1:

The invention merges the rotation action and plunger rod release action into a single integrated mechanism. By combining the needle cover rotation with the plunger rod release function, the device reduces multiple separate actions into one unified operation, improving ease of operation while maintaining reliable dose delivery through the engineered engagement between components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The needle cover serves multiple functions: it protects the needle, engages with the rotator to initiate rotation, and simultaneously controls the plunger rod release. This multi-functionality reduces the number of separate actions required while ensuring reliable dose delivery through the coordinated action of its various functions

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

3Reliability

If confirmation of injection completion is provided, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveconfirmation of injection completionVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drive mechanism incorporates an end of injection indication mechanism that provides feedback to the user when injection is complete. This feedback system uses the existing mechanical components (rotator, needle cover, plunger rod spring) to generate audible, tactile, or visual signals without adding complex separate indication systems, thereby improving reliability while minimizing increases in device complexity

Inventive Principle:
Principle #23Feedback

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

Simplifies the injection process, reduces human error, and ensures intuitive use with clear confirmation of dose delivery.

Implementation Method 1

a plunger rod spring positioned within a cavity defined by the rotator

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3452148B1Medicament delivery device with end of injection indication mechanism
Publication Date: 2025.10.15 SHL MEDICAL AG
  • EP3452148B1 patent drawingFigure 1
  • EP3452148B1 patent drawingFigure 2
  • EP3452148B1 patent drawingFigure 3A

AI summary

A drive mechanism for a delivery device comprising, a rotator comprising an outer surface and an inner surface, the rotator configured to rotate from a first position to a second position; a needle cover comprising an inner surface that engages the outer surface of the rotation. An end of injection device is positioned at least partially within a plunger rod spring, the end of the injection indication device providing a signal to a user of the drive mechanism that an injection has been completed.