Needle Assembly Rotor Locking Mechanism for Intradermal Injection Safety

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Solution Overview

Problem

Conventional needle assemblies for intradermal drug injection face issues with inconsistent activation of the safety function due to skin resistance, leading to incomplete displacement of the needle protection member and discomfort for the recipient.

Innovation Solution

A needle assembly design featuring a rotor with a restriction portion that rotates to lock the needle protection member in place, preventing re-displacement and ensuring reliable activation of the safety function without rotating against the skin, thus enhancing user comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the needle protection member rotates in the circumferential direction of the tubular needle while being pressed against the skin, then the safety function can be activated, but the needle protection member may rotate due to skin resistance and fail to reach the correct use position, causing the safety function to not activate

Engineering Contradiction:

Improvesafety function activationVSAvoiddisplacement to use position

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Instead of rotating the needle protection member itself against the skin, the invention rotates the rotor (a separate component) while the needle protection member remains stationary or moves linearly. This inversion separates the rotation function from the protection member, eliminating skin resistance issues while maintaining the safety activation mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The rotor acts as an intermediary component that mediates between the needle protection member and the safety function activation. The rotor receives rotational input and transmits it through the restriction portion to activate the safety mechanism, without the needle protection member itself needing to rotate against the skin.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the needle protection member rotates while in contact with the skin, then the safety function may be activated, but the skin may be pulled in the rotation direction causing discomfort to the drug recipient

Engineering Contradiction:

Improvesafety function activationVSAvoiddiscomfort to recipient

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention inverts the rotation mechanism by rotating the rotor instead of the needle protection member. This eliminates direct rotational contact with the skin, removing the source of discomfort while preserving the safety activation function through the rotor's rotational movement.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the restriction portion is displaced from initial position to lock position by rotor body rotating, then the needle protection member is prevented from re-displacement, but the structure becomes more complex

Engineering Contradiction:

Improveprevention of re-displacementVSAvoidstructure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the locking function with the rotor's rotational movement. The restriction portion on the rotor body naturally engages with the needle hub structure during rotation, combining the safety activation and locking prevention functions into a single integrated mechanism rather than separate components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotor's rotation itself generates the locking action through the restriction portion. As the rotor rotates to activate the safety function, the restriction portion automatically engages with the needle hub to prevent re-displacement, making the system self-locking without requiring additional active components.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11511050B2Needle assembly

Publication Date: 2022.11.29 TERUMO KK

AI summary

A needle assembly is disclosed, which includes a needle protection member and a rotor. The rotor has a rotor body and a restriction portion. When the needle protection member in the initial state is displaced from the protection position to a use position and returns to a protection position, the restriction portion is displaced from the initial position to the lock position by the rotation of the rotor body with respect to the needle protection member. A needle hub has a displacement prevention portion that prevents the needle protection member from being displaced from the protection position to the use position again by contacting the restriction portion at the lock position.