Syringe Finger Hooking Portion for Stable High-Force Administration

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Solution Overview

Problem

Existing syringes destabilize during high plunger pushing forces, leading to incomplete drug administration due to finger slippage and incorrect gripping, which can result in failure to administer the full specified dose.

Innovation Solution

A syringe design featuring a brim-shaped finger hooking portion and a sleeve-shaped gripping portion that allows stable holding with multiple fingers, preventing slippage and ensuring proper plunger activation, even with high pushing forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a syringe barrel flange is provided as a separate part, then the syringe can be assembled with standard components, but the syringe cannot be held stationary during high plunger pushing force administration

Engineering Contradiction:
Improveassembly with standard componentsVSAvoidstability during administration
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention merges the syringe barrel flange with the outer tube by providing a projection from the outer tube that functions as the flange. This integrated structure eliminates the need for separate assembly while providing a stable holding surface that prevents syringe movement during high-force plunger pushing, thereby resolving the contradiction between ease of manufacture and administrative stability.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the syringe is held with four fingers on the outer tube, then the syringe can be stabilized during high plunger pushing force, but the index finger may be caught between the proximal opening and pressing portion

Engineering Contradiction:
Improvestability during high plunger pushing forceVSAvoidfinger catching hazard
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention adds a radial dimension to the holding structure by providing a projection from the outer tube that extends outward. This creates a new dimensional space for finger placement that is radially offset from the axial path between the proximal opening and pressing portion, allowing stable four-finger holding while eliminating the risk of index finger catching hazards.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the syringe barrel flange protrudes in two directions, then the syringe can be held with index and middle fingers, but high plunger pushing force causes finger slippage toward the proximal end

Engineering Contradiction:
Improveinitial gripping capabilityVSAvoidfinger position stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention employs asymmetric design by providing a single projection from the outer tube that extends in one radial direction, rather than symmetric two-directional flanges. This asymmetric structure creates an asymmetric finger distribution pattern that balances the holding force and prevents slippage toward the proximal end during high plunger pushing force administration.

Inventive Principle:
Principle #4Asymmetry

4Reliability

If the gripping portion is made longer, then the syringe can be held more stably with multiple fingers, but the overall syringe length increases

Engineering Contradiction:
Improvestability during administrationVSAvoidgripping portion length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The invention applies local quality enhancement by concentrating the gripping function in a specific localized region through the projection from the outer tube. This projection provides enhanced friction and finger placement surface exactly where needed for stable holding, without requiring an increase in the overall length of the gripping portion or the syringe.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3127570B1syringe
Publication Date: 2020.05.06 TERUMO KK
  • EP3127570B1 patent drawingFigure 1
  • EP3127570B1 patent drawingFigure 2
  • EP3127570B1 patent drawingFigure 3(a)~3(b)

AI summary

A syringe that can firmly be held in a stable manner to administrate a liquid-drug into a subject person even when a high plunger pushing force is required and can be recognized by a user that the syringe is held by a grabbing manner to be used. The syringe includes: an syringe barrel 10 including an syringe barrel body 40 having a body portion 44 provided between a liquid-drug discharge portion 41 to which a cap 21 is attached and an insertion opening 46 opened at a proximal end, and an outer tube 30 that has an opening in a tube distal portion 31 at the distal end and an opening 39 at the proximal end, supports the syringe barrel body 40 by unmovably holding an syringe barrel flange 45, and includes a finger hooking portion 37a extending in one direction from the outer circumferential surface and a gripping portion 33 that can be held with fingers; and a plunger 50 having a shaft 51 inserted in the syringe barrel 10 through the opening 39 and a pressing portion 53 provided at the proximal end of the shaft 51. The syringe is preferably used as a prefilled syringe 1 storing a liquid-drug 100 in the body portion 44 in a liquid tight manner by a gasket 43 disposed in the body portion.