Autoinjector Anti-activation Cap and Shroud Lock

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Solution Overview

Problem

Autoinjectors can accidentally fire when subjected to sudden impacts, such as being dropped, even when a removable cap is in place, due to lack of a dedicated mechanism to prevent inward movement of the shroud, which can lead to unintended activation and drug delivery.

Innovation Solution

The autoinjector design incorporates inflexible formations on the cap and shroud that mechanically engage to prevent inward movement of the shroud when the cap is attached, using snap-fit engagement and angled surfaces to ensure secure locking and prevent accidental firing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a removable cap is provided to shield the shroud, then user contact with the shroud is prevented, but accidental firing can still occur due to sudden impacts causing inward movement of the shroud

Engineering Contradiction:

Improveuser contact with shroudVSAvoidaccidental firing prevention

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The inflexible formations on the cap and shroud are designed to preemptively prevent inward movement of the shroud before accidental firing can occur. The mechanical engagement creates a preliminary barrier that counteracts the harmful effect of impact forces before they can trigger the drive mechanism.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The inflexible formations act as a preliminary protective structure that absorbs and distributes impact forces before they can reach the shroud and trigger accidental firing. This prior protective measure ensures that even when the cap is attached, the shroud cannot move inward due to external impacts.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the cap is made removable for easy access, then ease of operation is improved, but the risk of accidental activation increases without additional locking features

Engineering Contradiction:

Improvecap removal and attachmentVSAvoidaccidental activation risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The inflexible formations create a preliminary mechanical barrier that prevents accidental activation while maintaining the removable nature of the cap. The formations engage before any accidental movement can occur, providing active protection rather than passive shielding.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS20250090765A1Autoinjector with Anti-activation feature

Publication Date: 2025.03.20 OWEN MUMFORD

AI summary

An autoinjector comprises a main housing for receiving a syringe or cartridge, a drive mechanism located within the main housing, and a shroud, coupled to a front end of the main housing and movable relative to the housing between an extended position in which a needle tip is substantially shrouded and a retracted position in which the needle tip can extend through an opening in the shroud. The shroud is coupled to the drive mechanism so that movement of the shroud causes a release of the drive mechanism, and the shroud is biased towards the extended position. A device cap and the shroud comprise respective substantially inflexible formations which are directly mechanically engageable with one another to prevent or restrict inward movement of the shroud relative to the housing when the cap is attached to the housing.