Syringe Gasket Pressing Mechanism for Interruptible Dose Control

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Solution Overview

Problem

Existing prefilled syringes do not allow for easy interruption of medicine administration or administration in batches, as the operation continues until the entire contents are discharged.

Innovation Solution

A gasket pressing tool that biases the gasket in a distal end direction, allowing for easy interruption and control of medicine discharge by releasing and re-engaging engagement protrusions using a mechanism with movement restriction members and an operation member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large number of gaskets are stacked together to form a gasket stack, then the gasket stack can serve multiple injection sites, but the gaskets tend to shift relative to one another causing misalignment

Engineering Contradiction:
Improvemulti-site injection capabilityVSAvoidgasket alignment
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The gasket stack is segmented into individual gaskets, each with registration features that divide and control the positioning of each component separately, preventing collective shifting while maintaining multi-site functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Registration features act as intermediary elements between the gasket stack and the anvil, providing a mediating mechanism that ensures precise alignment and prevents shifting during the molding process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If conventional molding techniques are used with stacked gaskets, then the process is simple, but the gaskets shift relative to one another causing misalignment

Engineering Contradiction:
Improvemolding process simplicityVSAvoidgasket alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The gasket stack performs self-alignment through integrated registration features that automatically position each gasket correctly without requiring complex external alignment mechanisms or procedures

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Registration features serve as intermediary elements that facilitate precise positioning between the gasket stack and molding apparatus, maintaining simplicity while achieving high alignment precision

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If gaskets are stacked to create a gasket stack for multiple injection sites, then versatility is improved, but alignment between gaskets becomes difficult to maintain

Engineering Contradiction:
Improvemulti-injection site capabilityVSAvoidalignment maintenance
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

Registration features act as intermediary positioning elements that automatically maintain alignment between multiple gaskets in the stack, eliminating the need for manual alignment maintenance while supporting multiple injection sites

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The registration features provide universal alignment functionality across all gaskets in the stack, enabling a single mechanism to maintain precise positioning for multiple injection sites simultaneously

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3760259B1Gasket pressing tool and liquid medicine administration tool using same
Publication Date: 2026.04.29 TERUMO KK
  • EP3760259B1 patent drawingFigure 1~3
  • EP3760259B1 patent drawingFigure 4~6
  • EP3760259B1 patent drawingFigure 7

AI summary

A gasket pressing tool 3 includes a syringe attachment member 4 attached to an outer tube 20, a gasket pressing member 8 that presses a gasket 22 of a syringe, a pressing member biasing body 11 accommodated in the gasket pressing member, a biasing body pressing tubular member 6 that accommodates a rear end portion of the pressing member biasing body and has side portions provided with opening portions 64 and 65, and movement restriction members 7a and 7b of the pressing member 8 held by the tubular member 6 and having engagement protrusions 72 that enter through the opening portions 64 and 65 of the tubular member 6. The pressing tool 3 has an engaged state maintaining function for the engagement protrusion 72 of the movement restriction member and the pressing member-side engagement portion 83 of the pressing member 8, and an operation function for the engagement protrusion 72 for releasing the engagement therebetween.