Needle Cover Undercut Design for Reduced Removal Force

Solution Overview

Problem

Existing needle covers for medical injection devices require a high pull-out force for removal, which can be challenging for users with reduced strength and may lead to accidental injury or needle bending during removal.

Innovation Solution

A needle cover design featuring an inner shield with a sealing connection and an outer shield with asymmetric undercuts and latching tabs, allowing for a reduced pull-out force while maintaining a tight seal and preventing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner needle shield is pressed tightly onto the tip to ensure sealing, then the sealing performance is improved, but the pull out force required for removal increases

Engineering Contradiction:

Improvesealing performanceVSAvoidpull out force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The needle cover is divided into two separate shields: an inner needle shield (30) responsible for sealing and an outer needle shield (101) responsible for protection. The inner shield maintains tight sealing contact with the tip, while the outer shield provides additional protection and includes undercuts to facilitate easier removal. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The outer needle shield incorporates undercuts (120, 122) that extend radially inward from the sidewall, creating a dimensional feature that engages with the inner shield. These undercuts provide mechanical interlocking in the radial direction while allowing longitudinal separation during removal, effectively reducing the pull out force through a dimensional design approach.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the inner needle shield is pressed tightly onto the tip to ensure sealing, then the sealing performance is improved, but the ease of operation for removal deteriorates

Engineering Contradiction:

Improvesealing performanceVSAvoidease of removal

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The needle cover is divided into two separate shields: an inner needle shield (30) responsible for sealing and an outer needle shield (101) responsible for protection. The inner shield maintains tight sealing contact with the tip, while the outer shield provides additional protection and includes undercuts to facilitate easier removal. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The undercuts (120, 122) in the outer needle shield are positioned asymmetrically at different locations around the circumference. This asymmetric arrangement creates multiple engagement points with the inner shield, providing balanced mechanical interlocking that facilitates uniform force distribution during removal, thereby improving ease of operation.

Inventive Principle:

Principle #4Asymmetry

3Ease of operation

If high pull out force is applied to remove the needle cover, then the needle cover can be removed, but the needle may bend or the user may be injured

Engineering Contradiction:

Improveremoval capabilityVSAvoidneedle bending and user injury risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The outer needle shield is pre-equipped with undercuts (120, 122) that are designed to engage with the inner shield at specific locations. This preliminary structural arrangement ensures that when removal force is applied, it is distributed through multiple engagement points rather than concentrated on a single point, preventing sudden jerks that could cause needle bending or user injury.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The outer needle shield incorporates undercuts (120, 122) that extend radially inward from the sidewall, creating a dimensional feature that engages with the inner shield. These undercuts provide mechanical interlocking in the radial direction while allowing longitudinal separation during removal, effectively reducing the pull out force through a dimensional design approach.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12324905B2Needle cover with undercut

Publication Date: 2025.06.10 BECTON DICKINSON FRANCE SAS

AI summary

A needle cover for protecting a needle mounted on a tip of a barrel of a medical injection device, may include an inner shield, and an outer shield surrounding at least partially the inner shield, and fixed to said inner shield, wherein the needle cover may include an outer shield including a body including a first open end, a second end, and a sidewall extending between the first end and the second end, the body defining a cavity to receive an inner shield therein, a first undercut defined adjacent the first open end of the body.