Syringe Seal Cap Non-Stick Projection Design

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Solution Overview

Problem

Existing seal caps for syringes are prone to unexpected removal during manufacturing and transportation, and tend to stick to the barrel during storage and sterilization processes due to direct contact with the barrel's surface, leading to potential contamination and handling issues.

Innovation Solution

A seal cap design featuring a non-stick surface and a projection portion that engages with an annular recessed portion on the barrel, preventing sticking and facilitating secure mounting while allowing for easy removal, even under sterilization conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the seal cap is designed with a smooth inner surface for easy assembly, then the assembly process is simplified, but the seal cap may stick to the barrel during storage and sterilization

Engineering Contradiction:
Improveassembly processVSAvoidsticking prevention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The inner surface of the seal cap is divided into two regions with different properties: a smooth assembly region for easy mounting and a non-stick region (treated with release agent or having different roughness) that prevents sticking during storage and sterilization. This local differentiation resolves the contradiction between easy assembly and sticking prevention.

Inventive Principle:
Principle #3Local quality

2Strength

If the seal cap has large contact area with the barrel for secure mounting, then the seal cap is firmly fixed, but it becomes difficult to remove the seal cap

Engineering Contradiction:
Improvemounting securityVSAvoidremoval ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The contact surface between seal cap and barrel is segmented into multiple discrete contact points rather than a continuous large area. This segmentation maintains sufficient mounting security while creating gaps that reduce overall adhesion and facilitate removal, resolving the contradiction between firm fixation and easy removal.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the seal cap is designed to be readily removable for user convenience, then the seal cap can be easily taken off, but it may be accidentally removed during manufacturing and transportation

Engineering Contradiction:
Improveremoval convenienceVSAvoidaccidental removal prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The seal cap incorporates a friction-based retention mechanism that provides dynamic resistance to removal. The cap can be easily removed when intentional force is applied by a user, but during normal handling and transportation, friction and the engagement structure prevent accidental removal. This dynamic behavior resolves the contradiction between ease of removal and prevention of accidental removal.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2974761B1Syringe assembly, syringe assembly packaging, seal cap for outer cylinder, and pre-filled syringe
Publication Date: 2020.08.12 TERUMO KK
  • EP2974761B1 patent drawingFigure 1
  • EP2974761B1 patent drawingFigure 2
  • EP2974761B1 patent drawingFigure 3

AI summary

A syringe assembly 10 according to an embodiment of the present invention includes a barrel 2, and a seal cap 3 mounted to the barrel 2. The seal cap 3 includes a closed distal end portion 31, an open proximal end portion 32, a hollow portion 30 including a barrel end storage portion 35 configured to store a barrel end portion 22, and a puncture needle storage portion 34 extending from the barrel end storage portion 35, an insertion allowing portion 33 configured to receive the insertion of a puncture needle tip 61 of a puncture needle 6 guided to the distal end of the puncture needle storage portion 34, and a projection portion 36 formed on an inner surface of the barrel end storage portion 35. The projection portion 36 has a top portion 36a disposed distal of the open proximal end portion 32, a distal inclined portion 36b extending distally from the top portion 36a, and a short proximal inclined portion 36c extending from the top portion 36a toward the open proximal end portion 32. A non-stick surface 9 for inhibiting sticking to a barrel end portion 22 of the barrel 2 is formed on an inner surface of the projection portion 36.