Syringe Protective Cap Elastic Lip Non-Return Mechanism

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Solution Overview

Problem

Existing syringe devices with non-return units fail to prevent the refitting of protective caps after the needle has been released, allowing potential reuse or contamination detection issues.

Innovation Solution

Incorporating an elastic lip forming a closed ring that is elastically constrained when the cap is in its protection position, making refitting virtually impossible due to its continuous configuration and diametral dimensions that are difficult to modify manually.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an elastic lip forming a closed ring is used to prevent refitting of the cap, then the reliability of preventing reuse is improved, but the device complexity increases

Engineering Contradiction:

Improveprevention of cap refittingVSAvoidstructure of non-return unit

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The elastic lip forms a flexible closed ring that can be elastically deformed during cap removal but returns to its original configuration to prevent refitting. This flexible structure provides reliable prevention without requiring complex mechanical components

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The elastic lip changes its diametral dimensions through elastic deformation when the cap is removed. The lip transitions from a constrained state during assembly to an expanded state that opposes refitting, utilizing parameter change to achieve the non-return function

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the elastic lip is joined to the cap or sheath, then the ease of manufacture is improved, but the ease of operation worsens due to difficulty in modifying diametral dimensions

Engineering Contradiction:

Improveattachment of elastic lipVSAvoidmanual refitting attempt

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The elastic lip is designed as a disposable component that is permanently fixed to either the cap or sheath. Once the cap is removed for needle access, the lip prevents refitting, ensuring the device cannot be reused. This aligns with the single-use nature of medical syringes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The elastic lip is a separate component that can be manufactured independently and then joined to the cap or sheath through overmolding or gluing. This segmentation allows for easier manufacturing while the lip's continuous closed-ring structure provides effective prevention against refitting

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If the cap is retained relative to the syringe body in protection position, then the protection of the needle is improved, but the ability to detect prior use worsens if refitting is possible

Engineering Contradiction:

Improveneedle contaminationVSAvoiddetection of prior use

Core Design Contradiction:

Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The elastic lip provides visual and tactile feedback to the user about whether the cap has been removed. Once the cap is removed for needle access, the lip's expanded configuration makes it obvious that the cap cannot be refitted, providing clear feedback that the device has been used

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The elastic lip is pre-configured in a constrained state during manufacturing that allows cap retention. Upon cap removal, the lip automatically transitions to its expanded state, preliminarily preventing any attempt at refitting and clearly indicating prior use before the user even attempts to refit the cap

Inventive Principle:

Principle #10Preliminary action

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 the cap cannot be easily refitted once removed, allowing users to verify if the syringe has been used or if the needle is soiled, enhancing safety and usability by preventing accidental or malicious reuse.

Implementation Method 1

an elastic lip which is joined to one of the elements formed by the sheath and the cap and which forms a closed ring, said lip being elastically constrained when the cap is in its protection position and adopting, in the free state, when the cap is separated from the body, a configuration able to oppose the refitting of the cap in the protection position

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8771235B2Syringe device with protective cap

Publication Date: 2014.07.08 TECH GRP EURO LTD

AI summary

The invention comprises a syringe body (10) having a distal end (10B) fitted with an injection needle (14), at least one sheath (16, 18) inside which the body is positioned, and a protective cap (40) able to be retained relative to the syringe body (10) to cover the needle (14) and be separate from this body to release the needle. The device comprises a non-return unit (50) able to oppose a refitting of the cap (40) in its protection position once the needle has been released. This non-return unit, for example, comprises an elastic lip (50) joined to the sheath or the cap.