Coffee Machine Shutoff Circuit Using Single-Phase Commutation

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Solution Overview

Problem

Existing coffee machines lack an efficient and economic control circuit for automatic shutoff, particularly due to the high voltage requirements for reacting to both phases of the power line, leading to functional and structural complications.

Innovation Solution

A control circuit that reacts to only one phase of the power line, utilizing a commutator with positions for different machine functions and a low-voltage electronic card, enabling automatic shutoff by shifting a single phase and incorporating a timer for elapsed waiting time detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the controller reacts to both phases of the power line to implement automatic shutoff, then the automatic shutoff function is achieved, but the circuit complexity and structural complications increase due to high voltage requirements

Engineering Contradiction:
Improveautomatic shutoff functionVSAvoidcircuit complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent segments the control function by separating the high-voltage power switching from the low-voltage control logic. The commutator handles phase switching at high voltage, while the electronic card operates independently at low voltage (5V) to detect elapsed time and trigger shutoff. This segmentation allows the controller to react to power line phases without requiring the entire control circuit to operate at high voltage, thereby reducing circuit complexity while maintaining automatic shutoff functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary approach by using the commutator as a mediator between the power line and the electronic card. The commutator shifts a single phase to supply the electronic card during ready-to-use periods, enabling the low-voltage controller to detect time elapsed without directly handling both high-voltage phases. This intermediary mechanism resolves the contradiction by allowing automatic shutoff control while keeping the electronic card's operating voltage low and circuit complexity reduced.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If the controller operates at high voltage to react to both phases of the power line, then the automatic shutoff function is implemented, but the electronic card complexity and cost increase

Engineering Contradiction:
Improveautomatic shutoff functionVSAvoidelectronic card simplicity and cost
Core Design Contradiction:
Extent of automationVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by fundamentally altering the operating voltage parameter of the electronic card from high voltage (230V) to low voltage (5V). This parameter change is enabled by the commutator's phase-shifting function, which provides isolated low-voltage supply to the electronic card. As a result, a simple and inexpensive 5V electronic card can be used instead of a complex high-voltage controller, significantly reducing manufacturing cost and complexity while maintaining the automatic shutoff function through elapsed time detection.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a simple low-voltage electronic card is used for automatic shutoff, then the circuit is simplified and cost is reduced, but the ability to react to power line phases is lost

Engineering Contradiction:
Improvecircuit simplicityVSAvoidautomatic shutoff function
Core Design Contradiction:
Device complexityVSExtent of automation

Solution Approach 1:

The commutator serves as an intermediary that bridges the gap between the simple low-voltage electronic card and the high-voltage power line. It shifts a single phase to provide power to the electronic card during ready-to-use periods, enabling the card to detect elapsed time and trigger shutoff without directly interfacing with both high-voltage phases. This intermediary mechanism allows the simple electronic card to perform automatic shutoff functionality that would otherwise require complex high-voltage circuitry.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces what would traditionally be a mechanical or high-voltage electronic control system with a low-voltage electronic card controlled by phase-shifting commutator. Instead of using a complex high-voltage controller to directly monitor both phases and execute shutoff, the system substitutes a simple 5V electronic card that only needs to detect elapsed time, while the commutator handles the phase-shifting and power management functions.

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

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 solution simplifies and reliable implementation of automatic shutoff, reducing complexity and cost by allowing the electronic card to operate at a low voltage, effectively managing power line phases for efficient machine operation.

Implementation Method 1

a commutator (2) for shifting a single phase chosen between L1 and L2, particularly the second phase L2

Methodology Applied
Scientific EffectPhase shifting:

Implementation Method 2

The by-pass circuit of the commutator 2 comprises in cascade a boiler (5), a first control thermostat (6) of the boiler (5) set with a first temperature T1, and a second control thermostat (7) of the boiler (5) set with a second temperature T2 lower than the first temperature T1

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a first control thermostat (6) of the boiler (5) set with a first temperature T1, and a second control thermostat (7) of the boiler (5) set with a second temperature T2 lower than the first temperature T1

Methodology Applied
Scientific EffectThermal detection:

Data Source

PatentEP2255704B1A circuit and control method for the self shutoff particularly of a coffee machine
Publication Date: 2011.11.09 DE LONGHI APPLIANCES SRL
  • EP2255704B1 patent drawingFigure 1

AI summary

The control circuit for the self shutoff particularly of a coffee machine, comprises a power line having a first phase (L1) and at least a second phase (L2), and a general power switch (1), a commutator (2) for shifting a single phase (L2), the commutator (2) having a first position in which a controller (3) of the general power switch (1) is powered for the automatic shutoff of the machine at reaching of a predetermined condition of the machine, and at least a second position (2b), in which a first actuating circuit of a first function of the machine is powered.