Dual-Material Syringe Tip Cap Assembly for Clean Sealing and Removal

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Solution Overview

Problem

Conventional syringe tip caps face issues with sealing integrity, contamination risk, and difficulty in removal due to material sticking, leading to potential contamination and economic loss.

Innovation Solution

A tip cap assembly comprising a rigid outer cap and an elastomeric inner cap, with a sealing ring and ribs, designed to securely engage with the syringe tip, ensuring airtight sealing and easy removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid tip cap is used to seal the syringe tip, then sealing integrity is improved, but the cap becomes difficult to remove due to material sticking

Engineering Contradiction:
Improvesealing integrityVSAvoidremoval ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tip cap is divided into two separate components: an inner cap made of elastomeric material and an outer cap made of rigid material. The inner cap remains on the syringe tip to maintain sealing integrity, while the outer cap can be easily removed by the user. This segmentation resolves the contradiction by assigning different functions to different materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner cap made of elastomeric material acts as an intermediary between the rigid outer cap and the syringe tip. It provides the necessary sealing function while allowing the outer cap to be easily removed without direct adhesion to the glass tip, thus preventing sticking.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If force is applied to engage a rigid tip cap with the adaptor, then connection strength is improved, but cracks may form in the adaptor or tip cap

Engineering Contradiction:
Improveconnection strengthVSAvoidstructural integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By separating the tip cap into inner and outer caps with different material properties, the system can achieve strong connection through the rigid outer cap to the adaptor while the elastomeric inner cap absorbs stress and prevents crack formation in the glass syringe tip.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The use of elastomeric material for the inner cap changes the mechanical parameters of the tip cap assembly, allowing it to deform elastically under stress rather than fracturing, thus preventing crack formation while maintaining connection strength.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the tip cap is made of rigid material, then structural stability is improved, but contamination risk increases due to potential displacement

Engineering Contradiction:
Improvestructural stabilityVSAvoidcontamination risk
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The segmentation of the tip cap into inner and outer parts allows the elastomeric inner cap to remain in direct contact with the syringe tip, providing a flexible seal that is less prone to displacement. The rigid outer cap provides structural stability but can be easily removed if displacement occurs, minimizing contamination risk.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If a single-material tip cap is used, then device complexity is reduced, but sealing performance and ease of removal cannot be simultaneously optimized

Engineering Contradiction:
Improvestructure simplicityVSAvoidsealing performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The tip cap uses composite construction with an elastomeric inner cap and a rigid outer cap, combining the advantages of both materials. The elastomeric material provides excellent sealing performance and flexibility, while the rigid material provides structural stability and ease of removal, achieving optimal balance without excessive complexity.

Inventive Principle:
Principle #40Composite materials

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 enhanced sealing integrity, prevents contamination, and facilitates easy opening, reducing the risk of fluid waste and patient safety issues.

Implementation Method 1

The inner surface of the sealing ring configured to engage the tip when the tip cap assembly is assembled with the container, the inner surface of the sealing ring comprises a plurality of ribs, and a surface of the ribs is configured to engage an outer surface of the tip of the container

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

An inner cap made of an elastomeric material and an outer cap made of a rigid material. The outer cap has a proximal portion configured to surround the tip of the container when the tip cap assembly is assembled with the container

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4316550B1Tip cap assembly for an injection system
Publication Date: 2026.03.25 BECTON DICKINSON FRANCE SAS
  • EP4316550B1 patent drawingFigure 1~2
  • EP4316550B1 patent drawingFigure 3~4
  • EP4316550B1 patent drawingFigure 5

AI summary

A tip cap assembly comprises a rigid outer cap and an elastomeric inner cap. The rigid out cap has a distal portion and a proximal portion. An inner surface of the distal portion defines a cavity configured to retain the elastomeric inner cap therein. An inner surface of the proximal portion defines a cavity configured to surround the tip of the container when the tip cap assembly is assembled with the container. A sealing ring is bonded to the inner surface of the proximal portion of the rigid outer cap. An inner surface of the sealing ring configured to engage the tip when the tip cap assembly is assembled with the container. The elastomeric inner cap is disposed within the cavity of the distal portion of the rigid outer cap.