Female Syringe Barrel Protrusions Prevent Over-Tightening

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Solution Overview

Problem

Existing syringe kits face issues with damage and deformation of syringe barrels due to excessive torque during connection, leading to deterioration in liquid tightness between the nozzle and cylindrical portion.

Innovation Solution

A female syringe barrel design featuring protrusions on its outer circumference that engage with a lock adapter's screw, preventing excessive tightening by advancing over the screw thread, and an abutment portion to suppress axis inclination, made from cyclic polyolefin for enhanced rigidity and toughness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If both screwing portions are screw-shaped to enable screwing connection, then the connection is achieved, but excessive screwing is possible causing damage and deformation

Engineering Contradiction:

Improvescrewing connectionVSAvoiddamage and deformation of syringe barrel

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The invention applies asymmetry by making one screwing portion (male) have a screw shape while the other (female) has a smooth cylindrical surface without screw threads. This asymmetric design allows the male portion to drive the connection through its screw threads while the smooth female portion resists excessive rotation, preventing over-tightening and damage to the syringe barrel.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If tapered surfaces are provided for connection, then liquid tightness is achieved, but excessive fitting causes deterioration in liquid tightness

Engineering Contradiction:

Improveliquid tightnessVSAvoiddeterioration in liquid tightness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The smooth cylindrical female screwing portion acts as a preliminary protective structure that resists excessive rotation before the tapered surfaces can be damaged. By providing this anti-rotation barrier in advance, the invention prevents the tapered sealing surfaces from being over-compressed or damaged, thereby maintaining liquid tightness.

Inventive Principle:

Principle #9Preliminary anti-action

3Strength

If the syringe barrel is made from rigid material for structural integrity, then strength is improved, but susceptibility to damage from excessive torque increases

Engineering Contradiction:

Improvestructural integrityVSAvoiddamage from excessive torque

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The smooth cylindrical female screwing portion serves as an intermediary protective element between the external torque and the main syringe barrel body. This intermediate structure absorbs and limits the transmission of excessive rotational force, protecting the barrel from torque-induced damage while maintaining overall structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11998722B2Female syringe barrel, syringe kit, and syringe connection method

Publication Date: 2024.06.04 TERUMO KK

AI summary

A female syringe barrel is disclosed, which includes two protrusions provided on a cylindrical portion. A length (Lp) of each protrusion of the two protrusions along a direction, perpendicular to an axis of the cylindrical portion and perpendicular to a direction in which each protrusion of the two protrusions protrudes from the cylindrical portion, is 2.0 mm to 4.5 mm. A width of each protrusion of the two protrusions along an axial direction of the cylindrical portion is 1.0 mm to 2.1 mm. Each protrusion of the two protrusions has an inclined surface, which opposes a trailing flank of a screw when the two protrusions are engaged into the screw of a lock adapter, in an end portion close to a barrel body.