Pipette Tip Ribs for Reduced Ejection Force

Solution Overview

Problem

Conventional pipette tips require high forces for plugging and ejecting due to steep spring characteristics and static friction, leading to user burden and increased energy consumption, especially when dimensional tolerances between the tip and attachment piece are not met.

Innovation Solution

The pipette tip features axially extending ribs that undergo partial plastic deformation upon plugging, storing part of the plugging force and providing lateral support, while elastic deformation in the seat area reduces the ejection force needed, minimizing the impact of dimensional tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pipette tip uses a conventional conical attachment design with elastic expansion, then sealing is achieved, but high plugging forces and high static friction result in high ejection forces and high energy consumption

Engineering Contradiction:

ImprovesealingVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The attachment piece is segmented into a conical portion and a cylindrical portion with different functions. The conical portion provides sealing through elastic expansion, while the cylindrical portion provides lateral support through plastic deformation of ribs, separating the sealing function from the support function to reduce overall ejection force and energy consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the deformation parameter of the attachment piece by introducing ribs that undergo plastic deformation instead of purely elastic deformation. This parameter change allows the attachment piece to maintain sealing while reducing the force required for ejection, thereby reducing energy consumption.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the pipette tip uses a conventional conical attachment design with elastic expansion, then sealing is achieved, but high plugging forces and high static friction result in high ejection forces requiring powerful motor drives

Engineering Contradiction:

ImprovesealingVSAvoidmotor power

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The attachment piece is segmented into a conical portion and a cylindrical portion with different functions. The conical portion provides sealing through elastic expansion, while the cylindrical portion provides lateral support through plastic deformation of ribs, separating the sealing function from the support function to reduce overall ejection force and energy consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the deformation parameter of the attachment piece by introducing ribs that undergo plastic deformation instead of purely elastic deformation. This parameter change allows the attachment piece to maintain sealing while reducing the force required for ejection, thereby reducing energy consumption.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If dimensional tolerances between pipette tip and attachment piece are not met, then assembly variability increases, but conventional designs lack compensation mechanisms leading to inconsistent sealing and ejection forces

Engineering Contradiction:

Improvedimensional toleranceVSAvoidsealing consistency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention changes the deformation parameter of the attachment piece by introducing ribs that undergo plastic deformation instead of purely elastic deformation. This parameter change allows the attachment piece to maintain sealing while reducing the force required for ejection, thereby reducing energy consumption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cylindrical portion with ribs acts as a compensation mechanism that beforehand cushions against dimensional tolerance variations. The plastic deformation of the ribs provides a compliance mechanism that accommodates variations in dimensional tolerances, ensuring consistent sealing and ejection forces despite manufacturing variations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

This design allows for reduced ejection forces, unburdening users and reducing energy consumption, especially for motor-driven ejectors, by utilizing stored elastic deformation instead of overcoming plastic deformation during ejection.

Implementation Method 1

the ribs (12) are partly plastically deformed

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

elastic deformation occurs in the seat area (30) outside of the ribs (12)

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 3

An air column is displaced by means of the gas displacer element, in order to aspirate liquid for the pipette tip sitting on the attachment piece, or to eject it from the same

Methodology Applied

Scientific EffectGas displacement: Pressure Gradient

Implementation Method 4

a correspondingly high static friction acts between the attachment piece and the pipette tip

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS9156030B2Pipette tip

Publication Date: 2015.10.13 EPPENDORF AG

AI summary

A pipette tip having the shape of an elongate small tube with a lower opening at the lower end for the passage of liquid, and an upper opening at the upper end, wherein a seat area exists on the inner circumference contiguous to the upper opening, which serves for plugging it onto a standardized conical attachment piece of a pipetting device, wherein the seat area has a retaining area with axially extending ribs projecting radially towards the inside, and below the retaining area a sealing area and is configured such that when the pipette tip is plugged onto the attachment piece with its seat area by a plugging force which ensures retaining and sealing of the pipette tip on the attachment piece, the ribs are partly plastically deformed, and elastic deformation occurs in the seat area outside of the ribs.