Coffee Grinder Load Cell Dosing to Reduce Weight Measurement Error

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Solution Overview

Problem

Current coffee grinders lack precision in measuring the weight of ground coffee due to indirect calculation methods, leading to heterogeneity in dosages and potential residue loss during the grinding process.

Innovation Solution

A coffee grinder with a load cell for direct weight measurement at the filter-holder, combined with a switching unit that alternates between weight-based and time-based dosing, using a reliability assessment and firmware for continuous calibration and self-learning adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If indirect calculation method based on grinding time is used, then device complexity is reduced, but measurement precision of coffee dosage weight deteriorates

Engineering Contradiction:
Improveweighing system complexityVSAvoiddosage weight precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the indirect mechanical timing system with a direct electronic weighing system using a load cell. The load cell directly measures the weight of ground coffee delivered to the filter holder, substituting the mechanical grinding-time-based dosage calculation with an electronic weight measurement system, thereby achieving both precision and simplified device architecture.

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

2Measurement precision

If direct weight measurement at filter-holder is implemented, then measurement precision of coffee dosage is improved, but device complexity increases

Engineering Contradiction:
Improvedosage weight precisionVSAvoidweighing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the weighing function into a separate, dedicated load cell component that is integrated into the existing filter holder support structure. By taking out the weighing function as an independent element and placing it where the filter holder is already supported, the system achieves direct weight measurement without adding significant structural complexity to the overall device.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If grinding process is optimized for precise dosing, then manufacturing precision of coffee dosage is improved, but productivity decreases due to extended calibration and measurement time

Engineering Contradiction:
Improvecoffee dosage uniformityVSAvoidgrinding speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the load cell continuously monitors the weight of ground coffee during the grinding process. The control unit receives real-time weight data and can adjust the grinding duration dynamically, providing feedback control that ensures precise dosing while optimizing grinding time to maintain high productivity without sacrificing dosage uniformity.

Inventive Principle:
Principle #23Feedback

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

Achieves high precision and constancy in coffee dosages, maintaining perfect calibration despite external conditions, with the ability to choose between weight-based and time-based dosing modes for optimal performance.

Implementation Method 1

a weighing system of the filter-holder with the ground coffee, said weighing system being operatively connected to said fork

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3873310B1Coffee grinder with weight control device of the dose of ground coffee
Publication Date: 2022.11.30 CMA MACCHINE PER CAFFE SRL
  • EP3873310B1 patent drawingFigure 1~2
  • EP3873310B1 patent drawingFigure 3~4
  • EP3873310B1 patent drawingFigure 5~6

AI summary

Coffee grinder with weight control device of the dose of ground coffee, of the type comprising an electric motor (3), a grinder group (4) driven by said electric motor (3) and housed inside a grinding chamber (5), a feed hopper (6) for feeding the coffee beans to be ground towards said grinding chamber (5), a delivery channel (7) for delivering the ground coffee towards a support fork (8) of a filter- holder to be loaded with ground coffee, a load cell (16) mechanically connected to said fork (8) and a microprocessor (17) which controls the operation of the motor (3) to determine a desired final dose (Pf) of ground coffee inside said filter-holder. Said microprocessor (17) contains control firmware which, when weighing a new dose of coffee is required by the user, activates a weighing program which provides the following operational steps in succession: a) activating the electric motor (3) to obtain the coffee grinding by the grinder group (4); b) continuously controlling, by said load cell (16), the detected weight (Pr) of ground coffee which, through said delivery channel (7), reaches the filter-holder leaning on said fork (8); c) determining the shutdown of the electric motor (3) when said detected weight (Pr) reaches the value Pr=Pf-A where Δ is a predetermined value corresponding to the weight of ground coffee which reaches the filter-holder during the shutdown transient of the electric motor (3).