Medicine Injection Tip Locking Mechanism for Reliable Needle Retraction

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Solution Overview

Problem

Existing medicine injection tips face difficulties in smoothly inserting and retracting needles into and from the skin due to reduced elastic force over time, leading to delayed or impaired functionality.

Innovation Solution

A medicine injection tip with a locking unit that includes a shaft, a needle unit, and a locking arm, which uses a hook recess and hook mechanism to securely lock and unlock the needle for smooth insertion and withdrawal, combined with a guide for controlled movement and a medicine supply unit for efficient medication delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring is used to provide elastic force for moving the needle, then the needle can be automatically retracted from the skin, but the elastic force decreases over time causing delayed or failed retraction

Engineering Contradiction:

Improveneedle retraction reliabilityVSAvoidspring life span

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent employs a disposable needle assembly where the needle and its associated elastic component are designed as a single-use unit. After one insertion and retraction cycle, the entire needle assembly is discarded, eliminating the problem of deteriorating elastic force from repeated use. This ensures reliable retraction performance for each new needle while avoiding the lifespan limitations of reusable springs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The injection device is divided into separate reusable and disposable components. The main body housing containing the motor and control systems is reusable, while the needle assembly with its elastic retraction mechanism is disposable. This segmentation allows the critical elastic force generation to occur in a fresh, unused component for each procedure, maintaining reliability without requiring long-lasting elastic components in the reusable portion.

Inventive Principle:

Principle #1Segmentation

2Strength

If a locking mechanism is added to secure the needle during movement, then the needle can be firmly held during insertion, but the device structure becomes more complex

Engineering Contradiction:

Improveneedle holding strengthVSAvoidlocking unit structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The locking mechanism is designed to engage and disengage automatically based on the positional relationship between the needle and the housing during insertion and retraction. The elastic component naturally drives the needle into the locked position during insertion, and the same elastic force automatically releases the lock during retraction. This self-service locking eliminates the need for additional actuators, sensors, or control systems, maintaining structural simplicity while providing firm needle holding strength when needed.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The locking mechanism transitions between locked and unlocked states dynamically based on the needle's movement phase. During insertion, the mechanism is locked to provide firm holding strength. During retraction, the elastic force automatically unlocks it. This dynamic behavior is achieved through the mechanical interaction of simple components rather than complex control systems, resolving the contradiction between holding strength and structural complexity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20220370731A1Medicine injection tip, hand piece, and skin treatment device

Publication Date: 2022.11.24 JEISYS MEDICAL INC

AI summary

Disclosed are a medicine injection tip that may smoothly insert and discharge a needle into and from skin, a hand piece, and a skin treatment device.