Coffee Grinder Bearing Layout for Consistent Disc Spacing

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Solution Overview

Problem

Conventional grinding mechanisms experience bending loads and fluctuations in grinding disc distance due to central bearing arrangements, leading to uneven grinding and potential mechanical stress, while also facing issues with material blockages and overheating due to inefficient discharge channels.

Innovation Solution

The introduction of angular bearings positioned radially outside the grinding discs, supported by a ring-shaped angular ball bearing and a plain bearing with a spring washer, along with a sealing ring to prevent material ingress, and driver lugs for efficient material removal, ensures stable operation and consistent grinding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If central bearing arrangement is used to support the grinding disc holder, then the structure is simple and easy to manufacture, but bending loads cause fluctuations in grinding disc distance and uneven grinding

Engineering Contradiction:
Improvebearing arrangement simplicityVSAvoidgrinding disc distance consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent transitions from a central axial bearing arrangement to a radial bearing arrangement located at the periphery of the grinding disc holder. This dimensional change in bearing placement eliminates the long lever arm that caused bending moments, allowing the grinding discs to maintain consistent spacing without requiring complex compensation mechanisms.

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

2Strength

If high-strength materials are used for grinding discs to withstand bending loads, then mechanical strength is improved, but manufacturing cost increases and machining difficulty increases

Engineering Contradiction:
Improvegrinding disc mechanical strengthVSAvoidgrinding disc manufacturing cost and machining
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies bearings in advance at the radial periphery of the grinding disc holder to prevent bending loads from occurring during operation. By eliminating the source of bending moments through proper bearing placement, ordinary materials can be used instead of expensive high-strength materials, significantly reducing manufacturing costs and machining complexity.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If large volume regrind channel is designed to prevent blockages, then material flow reliability is improved, but the channel volume increases and ground material remains too long causing aroma loss and overheating

Engineering Contradiction:
Improvematerial discharge reliabilityVSAvoidregrind channel volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent changes the geometric parameters of the regrind channel by adding driver lugs that actively transport ground material along the channel. This allows for a smaller channel volume while maintaining reliable material flow, as the driven transport mechanism prevents blockages without requiring excessive channel capacity.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If conventional central bearing arrangement is used, then device complexity is low, but grinding disc holder experiences severe bending stress leading to potential disc breaking

Engineering Contradiction:
Improvebearing arrangement complexityVSAvoidgrinding disc holder durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces radial bearings as intermediary support elements at the periphery of the grinding disc holder. These bearings act as mediators that directly support the grinding disc assembly, eliminating the transmission of bending loads through the holder structure and preventing disc breaking without significantly increasing overall device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 minimizes bending loads, maintains a consistent grinding degree, extends the service life of the grinder, and allows for a smaller, lighter, and potentially cheaper construction while ensuring continuous material discharge and preventing overheating.

Implementation Method 1

a spring washer (16) is provided as a plain bearing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a felt sealing ring (12) is provided in the housing (2)

Methodology Applied
Scientific EffectPhysical barrier: Physical Containment

Implementation Method 3

The material to be ground, which is fed in from the middle, is crushed by the grinding discs

Methodology Applied
Scientific EffectMechanical crushing: Mechanical Force

Implementation Method 4

conveyed outwards into a surrounding grinding channel by centrifugal force

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2404534B1Grinder
Publication Date: 2014.08.13 SEVERIN ELEKTROGERATE
  • EP2404534B1 patent drawingFigure 1~2
  • EP2404534B1 patent drawingFigure 3~4
  • EP2404534B1 patent drawingFigure 5

AI summary

Grinder (1) for ground material, in particular coffee beans, with a housing (2), a grinding disk holder (4) which is rotatably mounted in the housing (2) and on which a first annular grinding disk (5) is fixed, and which is held non-rotatably in the housing (2). second annular grinding disk (6), an overhead housing opening (3) for filling in ground material, a discharge opening (19) formed on the side of the housing for ground flour, and an electric drive (9) for rotating the grinding disk holder (4). so that bending loads on the grinding disks are largely avoided and a constant degree of grinding of the material to be ground is achieved, it is proposed that an angular contact bearing (11) is arranged between the grinding disk holder (4) and a housing part (10), namely vertically or axially below the annular grinding disks ( 5.6).