Coffee grinder, coffee machine and method for grinding coffee in a coffee grinder

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Solution Overview

Problem

Existing coffee grinders face issues such as large size, high power consumption, inefficiency, and operational delays due to clogged coffee grounds, particularly when using AC or conventional DC motors, and require significant adaptation when motor specifications change.

Innovation Solution

A coffee grinder with a two-part housing and a brushless DC motor positioned within the lower part, allowing for a compact design, adjustable grind size, and controlled speed, along with a reversible connection for flexible outlet positioning, and a control unit for managing blockages and grind settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If AC motors are used to power coffee grinders, then the motors can be directly powered by mains without strain on power supply, but the motors require significantly larger size and generate high heat and thermal expansion

Engineering Contradiction:
Improvepower supply compatibilityVSAvoidmotor size
Core Design Contradiction:
Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The patent replaces the AC motor with a DC motor, substituting one electrical system for another. The DC motor is driven by a power supply circuit that converts mains power to appropriate DC voltage, eliminating the need for a large AC motor while maintaining direct mains power compatibility. This substitution resolves the contradiction by achieving power supply compatibility through a different electrical approach that allows for compact motor dimensions.

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

2Use of energy by moving object

If AC motors are used in coffee grinders, then direct mains power connection is enabled, but the motors generate high degree of heat and thermal expansion

Engineering Contradiction:
Improvepower supply connectionVSAvoidheat generation
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent substitutes the AC motor with a DC motor system that includes a power supply circuit. This substitution eliminates the high heat generation problem inherent in AC motors while maintaining the ability to connect directly to mains power. The DC motor's efficiency and lower heat output resolve the contradiction between power supply compatibility and heat generation.

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

3Force

If conventional DC motors are used, then high starting torque is achieved, but the power supply must be correspondingly large to deliver high starting currents

Engineering Contradiction:
Improvestarting torqueVSAvoidpower supply size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent employs parameter changes by implementing a power supply circuit that dynamically adjusts voltage and current parameters. The circuit includes a microcontroller that monitors motor current and adjusts power delivery accordingly, enabling high starting torque when needed while reducing power supply size through intelligent parameter control rather than requiring a constantly oversized power supply.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by using a microcontroller-based power supply circuit that dynamically adjusts its output parameters based on real-time motor requirements. The system transitions between different power delivery states, providing high current during startup for high torque, then reducing current during normal operation, thereby eliminating the need for a continuously large power supply while maintaining high starting torque capability.

Inventive Principle:
Principle #15Dynamics

4Force

If conventional DC motors operate with very high starting currents under overload, then high torque is maintained, but the lifespan of the motors is reduced

Engineering Contradiction:
Improvetorque under overloadVSAvoidmotor lifespan
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent implements feedback through a microcontroller that continuously monitors motor current, temperature, and operational parameters. When overload conditions are detected, the control system adjusts power delivery to maintain necessary torque while preventing excessive current that would reduce motor lifespan. This closed-loop feedback resolves the contradiction by intelligently balancing torque requirements with motor protection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies beforehand cushioning by incorporating protective control logic that anticipates overload conditions and takes preventive action. The microcontroller monitors trends in current and temperature, and before damage occurs, it adjusts power delivery or triggers protective measures, thereby cushioning the motor against conditions that would reduce lifespan while still allowing necessary overload operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

5Force

If conventional DC motors are used, then high starting torque is achieved, but speed stability is poor and speed is load-dependent

Engineering Contradiction:
Improvestarting torqueVSAvoidspeed stability
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The patent implements feedback through a microcontroller that continuously monitors motor speed and adjusts power delivery to maintain constant speed despite load variations. The control system measures actual speed and compensates for load-dependent speed changes by adjusting voltage or current, thereby achieving both high starting torque and excellent speed stability that conventional DC motors lack.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by using a microcontroller-based control system that dynamically adjusts motor parameters in real-time. The system adapts power delivery based on instantaneous load conditions, maintaining optimal speed while preserving high starting torque capability. This dynamic control resolves the contradiction between torque and speed stability inherent in conventional DC motors.

Inventive Principle:
Principle #15Dynamics

6Ease of manufacture

If third-party motors are sourced for coffee grinders, then manufacturing flexibility is reduced, but the grinder housing must be adapted when motor specifications change

Engineering Contradiction:
Improvesourcing flexibilityVSAvoidhousing adaptation requirements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a standardized motor mounting interface and housing structure that can accommodate different motor specifications without requiring housing modifications. The power supply circuit is designed with universal compatibility, allowing the same housing to work with various DC motor types and sizes. This universal design resolves the contradiction by enabling manufacturing flexibility while eliminating the need for housing adaptations when motor specifications change.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 durable, high-quality ground coffee with minimal power consumption, reduced noise, and consistent dispensing capacity, while minimizing operational delays and installation space, and enhances flexibility for manufacturers.

Implementation Method 1

a second, lower, rotating grinding disc (6) connected to an output shaft of the housingless DC motor, wherein the housingless DC motor comprises a stator (8) and a rotor (9), the rotor (9) being connected to the second grinding disc (6)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4376684B1Coffee grinder, coffee machine and method for grinding coffee in a coffee grinder
Publication Date: 2026.01.28 WMF GROUP GMBH
  • EP4376684B1 patent drawingFigure 1
  • EP4376684B1 patent drawingFigure 2
  • EP4376684B1 patent drawingFigure 3

AI summary

The invention relates to a coffee grinder, a coffee machine and a method for grinding coffee in a coffee grinder. The coffee grinder is characterised in that it has a two-part housing and thus ensures maximum stability of the coffee grinder while requiring minimal installation space. The coffee grinder also has a DC motor. This motor enables the coffee grinder to provide ground coffee over a maximum life and without lengthy operational delays (e.g. caused by clogged coffee grounds) in the smallest possible installation space. The coffee grinder can be used in a coffee machine. In addition, the coffee grinder or coffee machine can be used in a method for grinding coffee, the coffee machine and the method providing the same advantages.