Spring-Loaded Needle Guard Locking Mechanism

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Solution Overview

Problem

Existing injection devices do not adequately prevent needle injuries after use, as users may forget to rotate the needle guard back into a safe position, leading to potential risks.

Innovation Solution

An injection device with a non-rotatable needle guard that automatically moves into a proximal end position upon activation, featuring a spring-loaded locking mechanism that blocks the needle guard from being pushed back, ensuring it remains in a safe position without user intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the needle guard is made rotatable to allow user repositioning, then ease of operation is improved, but reliability deteriorates because users may forget to rotate it back into a safe position

Engineering Contradiction:
Improveneedle guard repositioningVSAvoidneedle injury prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The needle guard automatically returns to its safe initial position after use through a spring mechanism, eliminating the need for user intervention. The system serves itself by automatically resetting to a protective state, ensuring needle coverage without relying on user memory or action.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring mechanism is pre-loaded during the injection process, storing energy that automatically propels the needle guard back to its protective position after use. This preliminary energy storage ensures the safety action occurs automatically without requiring subsequent user intervention.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the needle guard is automatically pushed back into the housing, then needle injury risk is reduced, but the device complexity increases due to additional locking mechanisms

Engineering Contradiction:
Improveneedle injury riskVSAvoidlocking mechanism structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into two independent locking elements (first and second locking elements) that operate at different stages of the needle guard movement. This segmentation allows each locking element to perform a specific function: the first prevents backward movement during injection, and the second prevents forward movement after use, simplifying the overall control logic while maintaining safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring acts as an intermediary element that mediates between the needle guard and the housing, providing the force necessary to automatically return the needle guard to its safe position while the locking elements control the movement boundaries. This intermediary mechanism achieves automatic positioning without complex control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the needle guard is blocked from moving back during injection, then injection accuracy is improved, but ease of operation worsens due to restricted movement

Engineering Contradiction:
Improveinjection accuracyVSAvoidneedle guard movement
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The needle guard transitions between different movement states dynamically: it is blocked during the injection phase to ensure accuracy, then automatically returns to its protective position after use. The locking elements are engaged/disengaged at appropriate times to provide temporary constraints only when needed for injection precision.

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

The device significantly reduces the risk of needle injuries by automatically securing the needle guard in a safe position after use, eliminating the need for user action to rotate it back, thus preventing accidental pricking.

Implementation Method 1

at least one resilient locking means (50b) by means of which the needle guard (9) can be blocked in a position guarding the needle

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2624882B1Locking and retaining mechanism for the needle guard sleeve of an injection device
Publication Date: 2021.04.28 YPSOMED AG
  • EP2624882B1 patent drawingFigure 1a~2b
  • EP2624882B1 patent drawingFigure 1c~2c
  • EP2624882B1 patent drawingFigure 2d

AI summary

Injection device having a mechanism for automatically discharging a product, further comprising a housing (1), a needle guard (9) at the distal end of the injection device, which needle guard (9) can be moved from its initial position into a proximal end position into the housing (1) and optionally from the proximal end position into a needle-guarding position, an activation mechanism (13) which can be moved from a non-activated position into an activated position, and when the needle guard (9) is in the non-activated position it is blocked in its ability to be moved into the proximal end position and when it is in the activated position can be moved into the proximal end position, wherein a resiliency arranged locking means (50, 50b) and a transmission means (51) which tenses and deflects the locking means (50; 50b) from a first position into a second position and is during the movement of the activation mechanism (13) into the activated position.