Coffee preparation device and method for determining a pressing force and a brewing pressure with such a coffee preparation device

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Solution Overview

Problem

Existing coffee preparation devices lack precise measurement of tamping force and brewing pressure, making it difficult to produce coffee drinks of consistently high quality.

Innovation Solution

A coffee preparation device with a force measuring device and evaluation/control unit to directly detect and calculate compression force and brewing pressure, using a plunger and holder to create a uniformly compacted coffee bed, and adjust brewing parameters for consistent quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual tamping is used, then operation simplicity is maintained, but measurement precision of compression force is lost

Engineering Contradiction:
Improvemanual tamping operationVSAvoidcompression force measurement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces manual mechanical tamping with an automated plunger mechanism driven by a motor, which applies compression force through a force measuring device (load cell or strain gauge). This substitution enables precise measurement of compression force while maintaining ease of operation through automation.

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

Solution Approach 2:

The patent introduces a force measuring device (load cell or strain gauge) as an intermediary between the plunger and the coffee grounds. This intermediary component enables precise measurement of compression force during the tamping process without interfering with the compression function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If brewing pressure is displayed via manometer, then measurement capability is provided, but measurement precision and automation are limited

Engineering Contradiction:
Improvebrewing pressure measurementVSAvoidbrewing pressure measurement automation
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The patent replaces the mechanical manometer with an electronic force measuring device (load cell or strain gauge) that directly measures brewing pressure as a force signal. This substitution enables more precise measurement and automated control of brewing pressure, as the electronic sensor can be integrated with the control system.

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

3Manufacturing precision

If no measurement of compression force is provided, then device complexity is reduced, but manufacturing precision of coffee quality is lost

Engineering Contradiction:
Improvecoffee quality consistencyVSAvoidmeasurement system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a force measuring device (load cell or strain gauge) as an intermediary component that measures compression force during tamping. This single measurement point provides sufficient data for the control system to adjust brewing parameters, enabling consistent coffee quality without requiring multiple complex measurement systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback control system where the measured compression force is used to automatically adjust brewing parameters (such as brewing pressure, water flow rate, or grind size) to maintain consistent coffee quality. The control system receives the force measurement signal and adjusts process parameters accordingly.

Inventive Principle:
Principle #23Feedback

4Adaptability or versatility

If multiple parameters are made adjustable, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvebrewing parameter adjustabilityVSAvoidparameter control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses the measured compression force as feedback to automatically adjust multiple brewing parameters (brewing pressure, water flow rate, grind size) through the control system. This feedback mechanism enables adaptability across multiple parameters while keeping the user interface simple, as the system automatically optimizes parameters based on the force measurement.

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

Enables precise measurement of compression force and brewing pressure, allowing easy production of high-quality coffee by adjusting brewing parameters such as brewing speed, grind size, and water supply.

Implementation Method 1

The force measuring device is designed to detect a compression force F1 that occurs when the plunger is moved in the predefined direction into the portafilter and acts on the coffee powder in the brewing chamber

Methodology Applied
Scientific EffectForce measurement: Force

Implementation Method 2

detecting an increased total force F2 on the holder, triggered by a brewing pressure occurring in a brewing chamber, also via the force measuring device

Methodology Applied
Scientific EffectForce measurement: Force

Implementation Method 3

The evaluation/control device is designed to calculate or determine a brewing pressure p = (F2-F1)/A in the brewing chamber by measuring the difference F2 - F1 between the forces F2 and F1 measured by the force measuring device and a surface A of the plunger facing the brewing chamber

Methodology Applied
Scientific EffectPressure calculation from force difference: Pressure Increase

Data Source

PatentEP4388945B1Coffee preparation device and method for determining a pressing force and a brewing pressure with such a coffee preparation device
Publication Date: 2025.11.12 BSH HAUSGERATE GMBH
  • EP4388945B1 patent drawingFigure 1~2

AI summary

The invention relates to a coffee preparation device (1), comprising a component (2) and a holder (6) for a portafilter (15) arranged thereon via a force measuring device (3), comprising a plunger (5) adjustable into the portafilter (15), which together with the portafilter (15) defines a brewing chamber (7), wherein the plunger (5) has a water inlet (9) leading into the brewing chamber (7), wherein the force measuring device (3) is designed to detect a compression force F1 acting on coffee powder (8) arranged in the brewing chamber (7) and a total force F2 acting on the portafilter (15) by the subsequent introduction of water into the brewing chamber (7), comprising an evaluation/control device (11) designed to determine the difference F2 - F1 between the forces F2, F1 measured by the force measuring device (3) and a surface facing the brewing chamber (7). (A) of the plunger (5) a brewing pressure p = (F2-F1)/A in the brewing chamber (7) is determined.