Medical Injector Rotating Body Trigger Mechanism

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Solution Overview

Problem

Existing medical injectors face issues with premature or failed trigger activations during automated plunger advancement, which can lead to inconsistent or incomplete medication delivery.

Innovation Solution

A medical injector design featuring rotatably coupled body portions, a displaceable plunger advanced by a spring, and a releasable retainer mechanism with latches and channels that allows controlled plunger advancement upon predetermined rotation, minimizing premature activations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a trigger mechanism is used for automated plunger advancement, then automated injection can be achieved, but premature or failed trigger activation occurs

Engineering Contradiction:
Improveautomated plunger advancementVSAvoidtrigger activation reliability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The device is divided into rotatable first and second body portions with distinct functional elements. The releasable retainer is integrated into the second body portion, while the plunger is positioned within the first body portion. This segmentation allows the retainer to control plunger release independently, preventing premature activation while maintaining automated functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The releasable retainer is pre-positioned to engage with the plunger before injection is required. The retainer's engagement feature is designed to automatically disengage at a predetermined rotation angle, ensuring the plunger is ready for injection only when intended, thus preventing premature activation while maintaining automation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a releasable retainer mechanism is used to control plunger position, then premature activation is reduced, but device complexity increases

Engineering Contradiction:
Improveplunger activation controlVSAvoidretainer mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The releasable retainer mechanism is merged with the rotatable body portions structure. The retainer's engagement feature is integrated into the second body portion, and the plunger is positioned within the first body portion. This merging reduces the number of separate components while maintaining reliable plunger control, thus reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The releasable retainer serves multiple functions: it holds the plunger in position, controls plunger release at a predetermined rotation angle, and prevents premature activation. By making the retainer multi-functional, the device avoids adding extra components, thereby reducing complexity while maintaining reliable plunger control.

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

3Reliability

If the plunger is retained in a fixed position, then injection consistency is improved, but ease of operation decreases

Engineering Contradiction:
Improveinjection consistencyVSAvoidplunger activation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retainer transitions from a static fixed-position constraint to a dynamic system that automatically releases at a predetermined rotation angle. This dynamic behavior allows the plunger to remain stable during storage (improving injection consistency) while automatically becoming operable at the correct moment (maintaining ease of operation).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The releasable retainer automatically disengages at the predetermined rotation angle without requiring user intervention. The system self-regulates the transition from retained to released state, ensuring consistent injection while maintaining ease of operation through automatic rather than manual release.

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 solution ensures reliable and automated plunger drive activation, reducing the likelihood of premature or failed injections and ensuring consistent medication delivery by allowing the spring to advance the plunger only upon specific rotational alignment.

Implementation Method 1

a spring configured to advance the plunger

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2331176B1Medical injector with rotatable body portions
Publication Date: 2020.10.28 BECTON DICKINSON & CO
  • EP2331176B1 patent drawingFigure 1
  • EP2331176B1 patent drawingFigure 2
  • EP2331176B1 patent drawingFigure 3

AI summary

A medical injector is provided herein which includes first and second body portions rotatabiy coupled together; a displaceable plunger disposed in at least one of the first and second body portions: a spring disposed to advance the plunger; and, a releasable retainer for retaining the plunger in a first portion against force of the spring. The releasable retainer releases the plunger upon a predetermined extent of relative rotation between the first and second body portions, thus allowing the spring to advance the plunger. Advantageously, the subject invention provides a medical injector having an automated plunger drive which is triggered upon rotation of injector body portions, thereby minimizing premature or failed activations.