Elastic Deformation Pipette Piston Locking Mechanism

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Solution Overview

Problem

Existing graduated measuring pipettes face issues with accuracy and reliability, particularly in low visibility conditions, as they require good visibility of graduations for precise dosing and often suffer from friction-based locking mechanisms that wear out or are insecure, leading to leaks and incorrect dosages.

Innovation Solution

A measuring pipette with an elastically deformable main body and a piston featuring a limiting member on its outer surface that applies a controlled compression force to prevent wall deformation, allowing precise stopping at desired graduations and enhancing visibility of the dosage level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a friction-based pad is used to lock the piston at the desired graduation, then the piston can be held in position, but the pad wears out over time leading to reduced friction force, leaks, and inaccurate dosing

Engineering Contradiction:
Improvepiston positioning reliabilityVSAvoidpad service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces the friction-based mechanical locking system with an elastic deformation-based locking system. The piston head creates a localized bulge in the main body wall through elastic deformation, which provides a mechanical interlock that does not rely on friction. This eliminates wear issues while maintaining reliable piston positioning at the desired graduation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent separates the locking function from the friction interface. Instead of relying on continuous friction between the pad and main body, the design creates a discrete elastic deformation zone that acts as a mechanical stop. This segmentation allows the locking function to be performed through geometric deformation rather than surface friction.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the main body is made of elastically deformable plastic material with a bead on the piston, then the wall can temporarily retain the piston through friction and deformation, but the system is not secure and the piston moves at the slightest pressure causing unexpected dosage changes

Engineering Contradiction:
Improvepiston positioning easeVSAvoiddosage accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the physical state and mechanical properties of the main body material to optimize elastic deformation characteristics. By selecting materials with specific elastic modulus and deformation properties, the system achieves a balance between ease of piston insertion and secure locking. The controlled elastic deformation creates a reliable mechanical interlock that prevents unintended piston movement while maintaining operational ease.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the insecure friction-based retention system with a controlled elastic deformation system. The localized bulge created by the piston head in the elastic wall provides a deterministic mechanical stop rather than relying on variable friction forces. This substitution ensures secure piston positioning that resists unintended movement under pressure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If existing pipettes require good visibility of graduations for precise dosing, then accurate measurement can be achieved in well-lit conditions, but dosing accuracy deteriorates in low visibility conditions such as at night

Engineering Contradiction:
Improvedosage measurement accuracyVSAvoidenvironmental lighting condition
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent incorporates visual enhancement features including colored bands or markings on the main body that provide high-contrast visual cues for graduation levels. These color-coded indicators remain visible and distinguishable under various lighting conditions, including low visibility environments. The use of contrasting colors and reflective or fluorescent materials ensures that the piston position and dosage level can be accurately determined regardless of ambient light intensity.

Inventive Principle:
Principle #32Color changes

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

Ensures reliable and precise dosing in all circumstances by allowing the user to set the piston stop position in advance, preventing overdosing or incorrect measurements, and improving readability of the dosage level without obstructing the view of the graduations.

Implementation Method 1

the wall of the main body elastically deforms locally at the bead of the piston, which temporarily retains the piston in the main body at the desired graduation by friction and deformation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a limiting member positioned on the outer surface of the wall of the main body and exerting a determined compression force to prevent the wall of the main body from deforming and thus stopping the stroke of the piston

Methodology Applied
Scientific EffectCompression force: Compression

Implementation Method 3

the wall of the main body elastically deforms locally at the bead of the piston, which temporarily retains the piston in the main body at the desired graduation by friction and deformation

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3453456B1Measuring pipette
Publication Date: 2020.04.08 ERCE MEDICAL
  • EP3453456B1 patent drawingFigure 1~2
  • EP3453456B1 patent drawingFigure 3~4
  • EP3453456B1 patent drawingFigure 5~9

AI summary

The invention relates to a measuring pipette (1) for the sampling and administration of a substance comprising at least: - a main body (2) including a first open end (2a), the main body (2) having an elastically deformable wall, - a piston (3) shaped to be inserted into the main body (2) by the first open end (2a) of said main body (2), the piston (3) including a first end (3a) configured to create a local elastic deformation (6) on the wall of the main body (2), characterized in that the measuring pipette (1) further includes a limiting member (4) arranged on the main body (2) and in that said limiting member (4) is configured to stop the stroke of the piston (3) in the main body (2) at a determined level.