Bearing System for Laboratory Mixer

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Solution Overview

Problem

Existing laboratory mixers face issues with unwanted twisting and tilting of the receiving device during mixing movements, leading to potential spills and contamination, due to the limitations of current bearing systems which can result in uncontrolled mixing movements and increased axial loads on the drive.

Innovation Solution

A mixing device with a bearing system featuring at least two supports, each with pivot bearings that have no translational degrees of freedom and two rotational degrees of freedom, and a guide device that synchronizes the movement of the receiving device relative to the chassis, ensuring a stable and controlled circular or elliptical path with minimal vertical deviations, thus preventing unwanted rotation and maintaining the receiving device's horizontal plane alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If linear roller bearings or linear plain bearings are used to mount the receiving device, then the mixing motion can be achieved, but the structure becomes complex and requires precise adjustment making it prone to failure

Engineering Contradiction:
Improvereliability of mixing deviceVSAvoidcomplexity of bearing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the problematic complex bearing structures (linear roller bearings, linear plain bearings) from the mounting system and replaces them with a simplified support structure consisting of supports with articulated bearings at both ends. This removes the harmful complexity while maintaining the essential mixing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the bearing configuration from single-point mounting to two-point articulated bearing mounting on each support. This parameter change in the bearing arrangement provides both rotational freedom and stability, resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If film hinge bearings are used to mount the receiving device, then the structure becomes simple and inexpensive, but fatigue failure occurs

Engineering Contradiction:
Improvesimplicity of bearing structureVSAvoidreliability of bearing
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses a composite bearing arrangement combining articulated bearings (providing rotational freedom) with supports and guide devices (providing stability and guidance). This composite structure maintains simplicity while eliminating the fatigue failure problem of pure film hinge bearings through the added stability of the support system.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If a vibrating frame is used to mount the receiving device, then the structure is simple, but increased axial load on the drive and risk of damaging the frame occurs

Engineering Contradiction:
Improvesimplicity of mounting structureVSAvoidaxial load on drive
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent segments the mounting function into separate components: supports for carrying the receiving device, articulated bearings for rotational freedom, and guide devices for guiding motion. This segmentation distributes forces appropriately, reducing axial load on the drive while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If articulated bearing supports are used without guide device, then the receiving device can move freely, but unintended rotation and tilting occurs leading to spills

Engineering Contradiction:
Improvefreedom of movementVSAvoidspillage and contamination
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a guide device as an intermediary element between the articulated bearings and the receiving device. This guide device mediates the motion, allowing necessary freedom of movement while preventing harmful unintended rotation and tilting that would cause spills.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Productivity

If the receiving device is allowed to rotate and tilt during mixing motion, then the mixing coverage is improved, but the main plane moves out of horizontal plane causing spills

Engineering Contradiction:
Improvemixing effectivenessVSAvoidspillage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a dynamic balance through the combination of articulated bearings (allowing dynamic adjustment) and guide devices (constraining dynamic motion to desired paths). This enables the receiving device to adapt dynamically during mixing while maintaining horizontal plane alignment to prevent spills.

Inventive Principle:
Principle #15Dynamics

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

The solution significantly reduces the risk of spills and contamination by maintaining the receiving device's horizontal plane alignment, reducing dynamic up and down movements, and minimizing the load on the drive, allowing for reliable mixing across a wide range of vessel sizes and volumes while extending the mixer's operational lifespan.

Implementation Method 1

The bearing has at least two supports, each with two spaced-apart articulated bearings, each having no translational and at least two rotational degrees of freedom

Methodology Applied
Scientific EffectArticulated bearing mechanism: Hinge

Implementation Method 2

The bearing has a guide device that guides the rotation of the receiving device relative to the chassis during the mixing movement

Methodology Applied
Scientific EffectGuidance mechanism:

Data Source

PatentEP2669000B1Mixing device with a bearing for a holder device, related mixing method and use of the mixing device
Publication Date: 2019.05.01 EPPENDORF AG
  • EP2669000B1 patent drawingFigure 1
  • EP2669000B1 patent drawingFigure 2
  • EP2669000B1 patent drawingFigure 3a

AI summary

The device (2) i.e. free-standing mixing device, has two supports (8) including bearing areas with two rotational degrees of freedom, without substantial translatory effect. A joint bearing mounts the supports to the chassis (4) and another joint bearing mounts a receiving device (6) to the supports. The bearings include a guidance device (28) for guiding the rotation of the receiving device relative to the chassis during the mixing movement. The bearings are spaced apart from each other with a rotational degree of freedom. The joint bearings are selected from any of a universal joint and a ball joint. An independent claim is also included for a method for mixing contents of laboratory vessels.