Needle-Free Injector Reset and Cassette Ejection Mechanism

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Solution Overview

Problem

Existing needle-free drug delivery devices face challenges with re-setting mechanism failures and manual handling of used cassettes, leading to reliability issues and contamination risks.

Innovation Solution

A needle-free device with a re-setting mechanism featuring a spindle retaining element and automatic cassette ejection mechanism, ensuring reliable re-use and minimizing contact with used cassettes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a re-setting mechanism is used to enable device re-use, then device versatility and productivity are improved, but reliability deteriorates due to mechanism failures

Engineering Contradiction:

Improvedevice re-use capabilityVSAvoidre-setting mechanism reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The spindle retaining element is extracted as a separate functional component from the piston assembly. It is positioned at the front end of the housing, independent of the piston, to exclusively retain the spindle in the axially offset position. This separation isolates the retention function from the actuation mechanism, reducing interference and improving reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The spindle retaining element acts as an intermediary component between the spindle and the housing. It provides a dedicated interface for retaining the spindle in the offset position without requiring direct engagement between the piston and spindle, thereby reducing mechanical complexity and failure points in the re-setting mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If manual handling of used cassettes is required, then device complexity is reduced, but safety deteriorates due to contamination risks

Engineering Contradiction:

Improvecassette handling mechanism complexityVSAvoidcontamination risk

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system performs self-service by automatically ejecting the used cassette from the housing. The reset spring, upon being compressed during actuation, automatically propels the cassette forward and outward, removing it from the device without requiring user intervention. This eliminates the harmful factor of manual handling and contamination risk.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The automatic ejection mechanism performs the cassette disposal action preliminarily, as part of the actuation sequence. The reset spring is compressed during the actuation process, storing energy that is then released to automatically eject the cassette immediately after use, before the user can handle it manually.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a spindle retaining element is added to prevent re-setting failures, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvere-setting mechanism reliabilityVSAvoiddevice structural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The spindle retaining element provides localized retention functionality at the front end of the housing where the spindle needs to be retained. Rather than redesigning the entire device structure, the retention function is applied locally at the specific location where it is needed, minimizing overall structural complexity.

Inventive Principle:

Principle #3Local quality

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 provides reliable and safe re-use by preventing re-setting failures and enabling hands-free cassette disposal, enhancing user safety and efficiency.

Implementation Method 1

a reset spring, positioned between spring seat and the front piston

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

a rear-end including a force generator and rear piston

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentEP4076587B1Improvements in needle-free delivery

Publication Date: 2026.04.15 AVAXMED LTD

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AI summary

The invention concerns improvements in needle-free devices for delivery of therapeutic and/or prophylactic agents, such as solid dose drugs, including vaccines. The needle-free device disclosed herein comprises novel structural arrangements and modes of actuation and operation, resulting in enhanced functionality and benefits to the user and/or patient.