Safety Needle Shield Locking for Automatic Tip Protection

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Solution Overview

Problem

Existing safety needle assemblies do not effectively prevent accidental needle stick injuries and require complex mechanisms for safe disposal.

Innovation Solution

A needle protection assembly comprising a base, a needle shield, a locking sleeve, a locking ring with engaging elements, and a biasing element that transitions between operative orientations through pressure application and release, ensuring the needle is safely protected after use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring is used to urge the shield away from the needle hub, then the shield automatically moves to cover the needle after injection, but the mechanism becomes more complex and requires additional components

Engineering Contradiction:
Improveautomatic needle coverageVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The biasing element automatically urges the shield to cover the needle after injection without requiring manual intervention or complex control mechanisms. The shield self-activates to protect the needle through the stored energy in the biasing element.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing element is pre-loaded during assembly to store potential energy, which is then released automatically after injection to drive the shield into the protective position, eliminating the need for additional actuation mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a locking mechanism is added to irreversibly lock the shield in place, then needle protection reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveneedle protection reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking function is separated into distinct locking elements that engage with specific locking positions on the needle hub, allowing independent optimization of each locking interface and simplifying the overall design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking elements are integrated with the shield structure, combining the protective function and locking function into a single unified component rather than separate mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the shield is made telescopically movable relative to the housing, then the needle can be exposed during injection and covered afterward, but the mechanism requires more components and complexity

Engineering Contradiction:
Improveneedle exposure and protectionVSAvoidshield movement mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shield is designed to be dynamically movable during injection to allow needle exposure, then automatically transitions to a static locked position after injection to provide protection, adapting its state based on operational phase.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shield is nested within the housing structure, allowing it to move telescopically in and out while maintaining a compact overall form factor, and can be locked at different positions along its travel path.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 assembly provides irreversible protection of the needle tip within the shield, enhancing safety by preventing accidental needle sticks and simplifying the disposal process.

Implementation Method 1

a biasing element (530) adapted for urging the shield (560) from the retracted position to the extended position

Methodology Applied
Scientific EffectSpring mechanism: Spring

Implementation Method 2

at least two locking elements (546, 554) extending radially outwardly from the guiding and locking ring (540)... adapted for engagement with at least two different locking positions on the needle hub (526)

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Data Source

PatentEP3370808B1Safety needles and methods of use thereof
Publication Date: 2026.01.07 DALI MEDICAL DEVICES
  • EP3370808B1 patent drawingFigure 1A~1D
  • EP3370808B1 patent drawingFigure 1E~1G
  • EP3370808B1 patent drawingFigure 2A~2D

AI summary

A needle protection assembly, adapted to protect a tip of a hypodermic needle, comprising a shield adapted, in a protected operative orientation of the needle protection assembly, to shield the tip of the hypodermic needle, a locking element including at least one slot, the slot including at least three surfaces corresponding to three operative orientations of the shield, at least one slot engaging element, functionally associated with the shield, the slot engaging element being disposed within the slot of the locking element and movable relative thereto, between the surfaces, so as to transition the shield between the three operative orientations, and at least one biasing element, adapted for axial biasing of the shield, wherein the three operative orientations include a storage operative orientation, an injection operative orientation, and a needle protection operative orientation.