Hybrid Needle Guard Structure for Passive Needle Stick Prevention

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Solution Overview

Problem

Existing needle guards for IV catheters require additional activation steps or are not effective in preventing accidental needle sticks, and there is a need for a cost-efficient manufacturing method.

Innovation Solution

A needle guard made of a combination of plastic and metal materials, with resilient arms and an adaptor, that automatically activates to cover the needle tip after withdrawal, using a hybrid structure to enhance resiliency and shelf life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a passive needle guard is used, then no additional activation steps are required, but the needle guard may not effectively prevent accidental needle sticks

Engineering Contradiction:
Improveactivation stepsVSAvoidneedle stick prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The needle guard is designed to automatically cover the needle tip through the resilient arms' inherent elasticity after needle withdrawal, without requiring any additional activation steps from the user. The resilient arms naturally return to their original position, providing self-activating protection.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The needle guard transitions from a static structure to a dynamic one by incorporating resilient arms that can deflect and return. This dynamic behavior allows the guard to automatically respond to needle withdrawal and actively cover the needle tip, combining ease of operation with reliable protection.

Inventive Principle:
Principle #15Dynamics

2Duration of action of stationary object

If a fully metal needle guard is used, then resiliency and shelf life are enhanced, but manufacturing cost increases

Engineering Contradiction:
Improveshelf lifeVSAvoidmanufacturing cost
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The needle guard combines plastic and metal materials to create a hybrid structure. The resilient arms are made of plastic for cost-efficient manufacturing, while metal reinforcement elements are strategically integrated to enhance resiliency and shelf life, achieving a balance between cost and performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Instead of making the entire needle guard from expensive metal, metal reinforcement is applied only to specific critical areas where enhanced resiliency is most needed. This localized approach maintains cost-effectiveness while providing sufficient durability and shelf life.

Inventive Principle:
Principle #3Local quality

3Strength

If a hybrid structure with metal reinforcement is used, then resiliency is enhanced, but device complexity increases

Engineering Contradiction:
ImproveresiliencyVSAvoidstructure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The needle guard is divided into distinct functional segments: plastic resilient arms for the primary guarding function and metal reinforcement elements for enhanced strength. This segmentation allows each material to be optimized for its specific role while simplifying the overall manufacturing process through modular assembly.

Inventive Principle:
Principle #1Segmentation

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

The hybrid needle guard effectively prevents accidental needle sticks and reduces manufacturing costs by utilizing a combination of materials that maintain resiliency over time.

Implementation Method 1

the first resilient arm, the second resilient arm, or both first and second resilient arms made from a metal material. In an example, the first resilient arm, the second resilient arm, or both first and second resilient arms have metal biasing plates placed in contact with exterior surfaces thereof or have metal inserts co-molded or insert molded with the first and second arms

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3996790B1Hybrid safety spring clip for sharp medical devices and related methods
Publication Date: 2026.02.18 B BRAUN MELSUNGEN AG
  • EP3996790B1 patent drawingFigure 1~2
  • EP3996790B1 patent drawingFigure 3~4
  • EP3996790B1 patent drawingFigure 5~6

AI summary

Needle guards (132) that can be made from a combination of plastic and metal can be used with sharp medical devices. The needle guard (132) can have a proximal wall (280) defining a distal surface (287), a proximal surface (286), and a through opening (284), the proximal wall (280) being made of a first material. The needle guard (132) can have a first resilient arm (288) extending distally from the distal surface of the proximal wall (280), the first resilient arm comprising an arm section and a distal wall (300). The needle guard (132) can have a second resilient arm (290) extending distally from the distal surface of the proximal wall (280), the second resilient arm (290) comprising an arm section and a distal wall (302). One of the first resilient arm and the second resilient arm can be made of a second material different from the first material of the proximal wall.