Automatic Injection Training Device Plunger Resistance

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Solution Overview

Problem

Existing automatic injection training devices lack accurate simulation of resistance during injection and proper needle cover locking, which are crucial for realistic user training.

Innovation Solution

An automatic injection training device with a reloadable plunger assembly, biased needle cover assembly, and actuation mechanism that provides audible feedback signals, simulating the injection process by coordinating ejection and retraction with uniform acceleration and resistance, and allowing for easy reload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing training devices are used, then basic injection training is possible, but accurate simulation of resistance during injection and needle cover locking is not achieved

Engineering Contradiction:
Improvesimulation accuracyVSAvoiddevice structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The device is divided into distinct functional modules: a needle cover assembly with locking mechanism, a plunger assembly with energy storage member, and a housing with guide channels. Each module independently performs its specific function (locking, propelling, guiding), allowing complex simulation capabilities while maintaining manageable structural complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A locking mechanism acts as an intermediary between the needle cover assembly and the plunger assembly. The locking mechanism engages with both components to simulate the actual injection device's safety features, providing accurate resistance simulation during the locking phase without requiring the entire device to be overly complex

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If a simple training device structure is used, then ease of manufacture is improved, but realistic user training experience is compromised

Engineering Contradiction:
Improvedevice fabricationVSAvoidtraining realism
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Complex features such as the locking mechanism and energy storage member are concentrated in specific localized areas of the device rather than being distributed throughout. The housing and guide channels provide simple structural support, while the specialized functional components are confined to specific assemblies, enabling realistic training experience in critical areas while maintaining overall manufacturing simplicity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The energy storage member is pre-loaded into the plunger assembly during manufacturing, and the locking mechanism is pre-configured in the needle cover assembly. This preliminary preparation of critical components allows the device to deliver realistic training experience upon activation without requiring complex assembly procedures or specialized manufacturing processes for the final product

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the needle cover assembly allows free movement, then ease of operation is improved, but accurate simulation of locking mechanism is not achieved

Engineering Contradiction:
Improvehandling convenienceVSAvoidlocking simulation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The needle cover assembly transitions between different dynamic states: a locked state where the locking mechanism engages to simulate the actual device's safety feature, and an unlocked state where the needle cover can move freely for reloading. This dynamic behavior provides accurate locking simulation during training while maintaining ease of operation for device preparation and reloading

Inventive Principle:
Principle #15Dynamics

4Device complexity

If the plunger is held in position without energy storage, then device complexity is reduced, but uniform acceleration and resistance simulation is not achieved

Engineering Contradiction:
Improvemechanical componentsVSAvoidinjection simulation accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The energy storage member (spring) is self-contained within the plunger assembly and automatically provides the necessary propelling force and resistance simulation during the injection phase. The spring's elastic properties inherently generate uniform acceleration and realistic resistance without requiring external control mechanisms, achieving accurate injection simulation while adding minimal mechanical complexity to the device

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

Enhances the realism of the injection simulation, providing users with a reliable and effective training experience through accurate simulation of resistance and needle cover locking, ensuring proper operation and safety during training.

Implementation Method 1

a first energy accumulating member configured to move the plunger from the first to the second position

Methodology Applied
Scientific EffectElastic potential energy: Spring

Implementation Method 2

a third energy accumulating member in the form of a compression spring, for urging the needle cover member towards the proximal end of the elongated housing

Methodology Applied
Scientific EffectElastic potential energy: Spring

Implementation Method 3

a second energy accumulating member arranged between the actuator sleeve and the actuator member

Methodology Applied
Scientific EffectElastic potential energy: Spring

Implementation Method 4

a friction element configured to interact with the tubular wall of the demo container such that when the plunger is released from the first position, a frictional resistive force between the friction element and the tubular wall of the demo container causes the plunger to be moved with a uniform speed and resistance

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3420549B1Automatic injection training device
Publication Date: 2022.11.02 SHL MEDICAL AG
  • EP3420549B1 patent drawingFigure 1
  • EP3420549B1 patent drawingFigure 2
  • EP3420549B1 patent drawingFigure 3

AI summary

The present invention relates to automatic injection training device (1) comprising: an elongated housing (2) having a distal (3) and an opposite proximal end (4) and extending along a longitudinally axis (L); a tubular demo container (19) axially and rotationally fixed relative to the elongated housing (2) and having a tubular wall (195) extending along the longitudinally axis (L); a reloadable plunger assembly (9) comprising a plunger (10) which is movable in the demo container (19) between a first and a second position and a first energy accumulating member (11) configured to move the plunger (10) from the first to the second position; an actuation assembly (15) configured to hold the plunger (10) in the first position; a biased needle cover assembly (60) comprising a needle cover member (6) which is movable in relation to the housing (2) from an extended position to a retracted position and from the retracted position to the extended position, wherein the needle cover member (6) is configured to interact with the actuation assembly (15) for releasing the plunger (10) when the needle cover member (6) is moved from the extended position to the retracted position and for preventing the needle cover member (6) to be moved when it is moved from the retracted position to the extended position.