Safety Needle Sleeve Locking for Automatic Post-Use Shielding

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Solution Overview

Problem

Existing safety needle devices require user intervention to activate safety features, posing risks of needlestick injuries and repeated use.

Innovation Solution

A safety needle device with a rotary sleeve and longitudinal resilient means that automatically activates upon needle withdrawal, preventing reuse through an irreversible blocking mechanism without additional user actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a safety needle device requires user intervention to activate safety features, then the device structure can be simpler, but the risk of needlestick injuries and repeated use increases

Engineering Contradiction:

Improvesafety against needlestick injuriesVSAvoiduser intervention required

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The safety needle device automatically activates its safety features through the patient's own body movements. When the patient moves their arm after injection, the relative motion between the needle hub and the housing triggers the automatic blocking mechanism, eliminating the need for user intervention to activate safety features

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The device is pre-configured with a blocking mechanism that is initially disengaged to allow needle movement during injection. The mechanism is designed to automatically engage after injection, preventing any further needle movement or reuse before the user can take additional actions

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a safety needle device uses an automatic blocking mechanism, then the risk of repeated use is reduced, but the device complexity increases

Engineering Contradiction:

Improveprevention of repeated useVSAvoidautomatic blocking mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The blocking mechanism is divided into separate functional components: a blocking element that can move between engaged and disengaged positions, and a triggering mechanism that detects needle movement. This segmentation allows each component to perform its specific function with simple geometry, reducing overall complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The safety blocking function is integrated into the existing needle hub and housing structure. The blocking element is positioned within the housing and works in conjunction with the needle hub's movement, combining multiple functions (support, blocking, and triggering) into a unified structure rather than adding separate independent components

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the slider is made longer to completely cover the needle when extended, then needle visibility is reduced for safety, but the device length increases

Engineering Contradiction:

Improveneedle coverage for safetyVSAvoidslider length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The slider is designed with dynamic positioning capability, allowing it to move between a retracted position during injection (where the needle tip remains visible for accurate positioning) and an extended position after injection (where it completely covers the needle for safety). This dynamic adjustment eliminates the need for an excessively long slider that would be required if it remained extended throughout the entire process

Inventive Principle:

Principle #15Dynamics

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

Ensures safe, automatic needle protection with minimal user effort, reducing the risk of needlestick injuries and ensuring single-use functionality while maintaining operational precision and comfort.

Implementation Method 1

a longitudinal resilient means, e.g. a spring, placed inside the housing, with its first end backed against the slider and its second end backed against the hub. The spring is at its lowest level of tension when the slider is maximally extended with its first end from the housing and the spring tension increases as the needle is inserted deeper

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentEP3749398B1Safety needle device

Publication Date: 2026.01.28 HTL STREFA SPOLKA Z O O

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AI summary

The device comprises an elongated needle (1) embedded in a hub (4) equipped with means for connecting the needle (1) with a vessel containing an injectable substance or a vessel for receiving tissue, a housing (9) mounted on the hub (4), a hollow slider (10) with its first end (15) directed towards the outside of the housing (9) and the second end (16) moving inside the housing (9) and means preventing slider rotation (13, 14, 39, 40) in relation to the housing (9). The device also includes a longitudinal resilient means (18) supported with its first end against the slider (10) and with its second end against the hub (4), blocking means (17, 23) stopping the slider's (10) movement in a position most extended from the housing (9) after removal of the needle (1) from the patient's body. The housing (9) features a cylindrical channel (20) in which there is a rotating sleeve (11) and the longitudinal resilient means (18). The side wall of the sleeve (11) features a linear notch (21) with a start bay (22) and a blocking bay (23). In the vicinity of the second end (16) of the slider (10) there is at least one pin (17) located transversely in relation to the needle's (1) axis and coupled mechanically to the linear notch (21) in the side wall of the rotating sleeve (11).