Coffee Grinder Impeller Design for Compact Bean Descent Without Noise

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Solution Overview

Problem

Existing grinders for automatic coffee machines face issues with user safety, noise, and compactness due to vibration-based bean descent mechanisms, which either result in material wastage or increased height, or require complex solutions to manage bean flow effectively.

Innovation Solution

A grinder design featuring a hopper with a reduced vertical dimension, equipped with a finger guard impeller that rotates via friction coupling with the internal grinder's shaft, limiting its angle of rotation to ensure complete bean unloading without discharge during reintegration, thus ensuring safety and silence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a vibration generator is added to the hopper to enable coffee beans to descend by gravity in a compact design, then the height dimension is reduced, but noise emissions are amplified and the machine operation is adversely affected

Engineering Contradiction:
Improvehopper heightVSAvoidnoise emissions
Core Design Contradiction:
Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies mechanical vibration through a cam mechanism that converts rotational motion of the grinder shaft into periodic vertical movements of the hopper bottom. This vibration agitates the coffee beans to facilitate their descent through the grinding gap without requiring an additional vibration generator, thereby avoiding noise amplification and adverse effects on machine operation while maintaining compact dimensions.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent merges the function of the grinder shaft with the vibration generation function by using the existing rotating shaft to drive a cam mechanism that vibrates the hopper bottom. This eliminates the need for a separate vibration generator, reducing noise emissions and simplifying the overall structure while achieving compact hopper design.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a fixed finger guard device is used to protect users in compact hoppers, then user safety is improved, but coffee beans cannot descend effectively without a vibration generator

Engineering Contradiction:
Improveuser safetyVSAvoidbean descent efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The cam mechanism generates vibrations that agitate coffee beans against the fixed finger guard device, enabling effective bean descent and feeding into the grinding gap while maintaining the protective function of the fixed guard structure.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The cam mechanism produces periodic vibrations at specific frequencies that enhance bean flow dynamics, allowing beans to overcome the barrier of the fixed finger guard and descend efficiently into the grinding area.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the hopper walls are made very inclined to enable bean descent by gravity, then bean flow is improved, but the height dimension increases limiting field of use

Engineering Contradiction:
Improvebean flowVSAvoidhopper height
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The vibration generated by the cam mechanism compensates for less inclined hopper walls, enabling effective bean descent and flow without requiring excessive height. The vibration agitates the beans to overcome gravity limitations in compact geometries.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the physical state and movement characteristics of coffee beans through vibration, transforming them from a static gravity-dependent flow to a dynamically agitated flow that can effectively descend in compact, less inclined hopper configurations.

Inventive Principle:
Principle #35Parameter changes

4Length of stationary object

If a rotatable finger guard device with coffee bean movement organs is used, then bean descent is achieved in compact hoppers, but coffee beans can be thrown out of the hopper creating material waste and safety risks

Engineering Contradiction:
Improvehopper heightVSAvoidcoffee bean waste
Core Design Contradiction:
Length of stationary objectVSLoss of substance

Solution Approach 1:

The patent extracts the bean movement function from the finger guard device itself and transfers it to the hopper bottom through the cam mechanism. The finger guard remains a fixed protective barrier while the vibration at its base agitates beans downward, preventing them from being thrown out while maintaining compact dimensions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The vibration generated by the cam mechanism acts as an intermediary force that agitates coffee beans at the base of the fixed finger guard, directing them downward into the grinding gap without requiring the guard itself to rotate or move, thereby preventing bean ejection while achieving compact design.

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

The solution provides a safe, silent, and compact grinder that effectively manages bean descent within a reduced vertical space, preventing material loss and noise, while simplifying construction by integrating the impeller's rotation with the internal grinder's shaft.

Implementation Method 1

the impeller is activated in rotation by the rotation shaft of the internal grinder through a friction coupling

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Hoppers of the known type have very inclined walls that allow the coffee beans to descend by gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3073878B1Grinder for automatic coffee machine
Publication Date: 2018.01.31 DE LONGHI APPLIANCES SRL
  • EP3073878B1 patent drawingFigure 1
  • EP3073878B1 patent drawingFigure 2
  • EP3073878B1 patent drawingFigure 3

AI summary

The grinder (1) for an automatic coffee machine, comprising an internal grinder (2) and an external grinder (4) separated by a gap (5), a hopper (13) equipped with an opening (14) for unloading the coffee beans in the gap (5) in order to perform the grinding, a finger guard impeller (15) positioned at said unloading opening (14) and having organs (16) for moving the coffee beans, and interception means of the impeller (15) configured and arranged to limit its angle of rotation.