Door Lock Circuit Segmentation to Reduce Voltage Interference

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Solution Overview

Problem

Existing door locks for electrical appliances suffer from unreliability due to the linkage between a sensing device connected to a low-voltage power source and an operating circuit connected to a high-voltage power source, leading to potential malfunctions.

Innovation Solution

A door lock design featuring a main slider, operating circuit, sensing circuit, and switches, where the operating circuit is powered by a high-voltage source and the sensing circuit by a low-voltage source, with the main slider reciprocating to control the connection and disconnection of these circuits through a sensing switch driving member, ensuring separation of high and low-voltage components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the sensing device is connected to the operating circuit, then the door state can be detected, but high-voltage and low-voltage components become mixed leading to potential malfunctions

Engineering Contradiction:
Improvedoor state detectionVSAvoidvoltage interference
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the electrical system into distinct voltage domains: the sensing circuit operates in the low-voltage domain (connected to terminal 106) and the operating circuit operates in the high-voltage domain (connected to terminal 104). This spatial and electrical segmentation prevents voltage interference while maintaining complete door state detection capability through the independent sensing circuit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different voltage characteristics to different parts of the system: the sensing circuit and its components (sensing switch, sensing switch driving member) are designed for low-voltage operation, while the operating circuit and its components (operating switch, main slider) are designed for high-voltage operation. This localized voltage assignment eliminates cross-voltage interference while preserving detection functionality.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4624704A1Door lock and electrical appliance including same
Publication Date: 2025.10.01 ILLINOIS TOOL WORKS INC
  • EP4624704A1 patent drawingFigure 1A
  • EP4624704A1 patent drawingFigure 1B
  • EP4624704A1 patent drawingFigure 1C

AI summary

The present application provides a door lock and an electrical appliance including same. The door lock includes a main slider, an operating circuit and an operating switch, a sensing circuit and a sensing switch, and a switch box. The operating circuit and the operating switch are arranged inside the switch box, and the sensing circuit and the sensing switch are arranged outside the switch box. The door lock of the present application includes the sensing circuit and the sensing switch to allow the electrical appliance to independently indicate the states of the door and the door hook of the electrical appliance, meeting more operational requirements of the electrical appliance and providing more possibilities for intelligent designs. And, the sensing circuit and sensing switch of the door lock of the present application are arranged outside the switch box and are separated from the operating circuit, which avoids the arrangements of both high-voltage and low-voltage power sources inside the switch box, thereby improving the reliability of the sensing circuit and the operating circuit.