Needle Cover Locking Mechanism to Prevent Syringe Re-Exposure

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Solution Overview

Problem

Existing syringes with safety mechanisms face issues where the needle cover can inadvertently slide from a protection position to an exposed use position, causing potential pricks, especially during transport or before use, and are difficult to remove the needle cap due to interference from the displaced needle cover.

Innovation Solution

A syringe design featuring a holder with a locking mechanism that locks the needle cover in place at both the use and protection positions, utilizing protruding and restriction portions to prevent axial displacement, and a guide groove for controlled rotation during position change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the needle cover is made displaceable from use position to protection position, then safety against inadvertent prick is improved, but the needle cover may inadvertently displace back to use position causing harm

Engineering Contradiction:

Improvesafety against inadvertent prickVSAvoidinadvertent needle exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The needle cover is designed with dynamic positioning capability, allowing it to move between use position and protection position based on operational needs. The locking mechanism provides dynamic control to maintain the cover in the protection position after use, preventing inadvertent displacement back to the use position and ensuring continuous safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A locking mechanism acts as an intermediary element between the needle cover and the syringe body. This locking mechanism engages with the needle cover to maintain it in the protection position, preventing unintended displacement while allowing intentional movement when needed. The locking mechanism serves as a mediator that ensures safety without restricting necessary operational flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the needle cover is displaced to protection position before use, then safety is improved, but removal of needle cap becomes difficult

Engineering Contradiction:

Improvesafety mechanism activationVSAvoidneedle cap removal

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to engage automatically when the needle cover is displaced to the protection position, providing preliminary safety activation. However, the mechanism includes features that allow easy disengagement when needed, such as manual release features or automatic release when the needle cap is reattached, ensuring that safety is activated without permanently complicating the removal operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The locking mechanism is designed to be temporarily active during transport and storage, then automatically deactivated or reset when the needle cap is reattached. This allows the system to discard the locked state during handling and recover the ease of operation needed for needle cap removal, maintaining both safety and usability at different operational stages.

Inventive Principle:

Principle #34Discarding and recovering

3Stability of the object's composition

If locking mechanism is added to hold needle cover, then stability at positions is improved, but device complexity increases

Engineering Contradiction:

Improveneedle cover position stabilityVSAvoidholder structure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The locking mechanism is segmented into discrete functional elements that can be independently designed and assembled. The holder includes separate locking portions that engage with the needle cover at specific positions, allowing the stability function to be achieved through modular components rather than a monolithic complex structure. This segmentation reduces overall design complexity while maintaining position stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking mechanism is designed to perform multiple functions: it locks the needle cover at the protection position to prevent inadvertent displacement, and it also facilitates the removal operation by engaging and disengaging appropriately. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in device complexity while achieving stable positioning.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12485230B2Syringe with safety mechanism

Publication Date: 2025.12.02 NIPRO CORP

AI summary

A safety mechanism syringe includes a syringe, a needle, a holder, and a needle cover displaceable relatively with respect to the syringe along an axial direction of the syringe from a use position toward a protection position. The holder includes a locking portion. At least one member of the holder and the needle cover includes a protruding portion that protrudes toward the other member, and the other member includes a restriction portion that abuts on the protruding portion to restrict relative displacement of the needle cover with respect to the syringe along the axial direction of the syringe from the protection position toward the use position.