Two-Wire Door Lock Circuit for Closing and Lock Detection
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Solution Overview
Problem
Existing door locking devices for household appliances require a minimum of three to six connecting contacts to check the closing and locking conditions, leading to complex designs, increased production costs, and bulkiness, which are not cost-effective and efficient.
Innovation Solution
A simplified door locking device using a circuit with only two connecting contacts to the machine electronics, comprising a door closing switch, an actuator, and a door locking switch arranged in series, with a resistance in parallel to the locking switch, allowing detection of both door closing and locking conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a door locking device uses three to six connecting contacts to detect door closing and locking conditions, then the detection function is reliable, but the device complexity and production costs increase
Solution Approach 1:
The patent combines the door closing detection function and door locking detection function into a single two-wire circuit. The first wire carries signals for both door closing detection (via first switch) and locking detection (via second switch), while the second wire serves as common reference. This merging of functions into a unified circuit eliminates the need for separate detection circuits, reducing wire count from 3-6 to just 2 wires while maintaining full detection capability.
Solution Approach 2:
The two-wire circuit design makes each wire serve multiple functions. The first wire simultaneously serves as: (1) signal line for door closing detection, (2) signal line for locking detection, and (3) power/reference line. The second wire serves as common reference for both detection functions. This multi-functionality reduces the overall wire count while maintaining all necessary detection capabilities.
2Measurement precision
If a door locking device uses three to six connecting contacts, then the detection accuracy is sufficient, but the production costs and wiring costs increase
Solution Approach 1:
The patent merges multiple detection functions into a single two-wire circuit, eliminating the need for multiple separate connections. By using switches that can be actuated by the same wire pair, the circuit achieves accurate detection of both door closing and locking states without requiring additional wires, thereby reducing material costs and assembly complexity.
Solution Approach 2:
The two-wire circuit design makes each wire serve multiple functions - carrying both power and signal information for different detection purposes. This reduces the bill of materials (fewer wires/connectors), simplifies assembly procedures, and lowers production costs while maintaining detection accuracy through proper switch actuation mechanisms.
3Reliability
If a door locking device uses three to six connecting contacts, then the detection capability is complete, but the device size and assembly complexity increase
Solution Approach 1:
The patent combines door closing detection and locking detection into a single integrated two-wire circuit. The first switch detects door closing by actuating between the first and second wires, while the second switch detects locking by actuating between the same wires. This unified approach reduces the number of connection points from 3-6 to just 2, simplifying assembly and reducing the physical size of the connection interface.
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 configuration reduces production and wiring costs, results in a more compact design, and effectively detects the door's closing and locking conditions, meeting safety standards while being cost-effective and easier to assemble.
Implementation Method 1
The actuator 24 may be actuated by supplying energy, in form of pulse actuation, through the first and the second connecting contacts 20 and 34
Implementation Method 2
In order to obtain the locking of the door with electromagnetic actuator or thermomagnetic actuator
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The present invention relates to a door locking device (1) for household appliances. The device according to the present invention allows to detect a door closing or opening condition, to actuate, only with the door closed, an electromagnetic actuator (40) that triggers door locking means and a respective switch (50), and finally to detect the door locking condition. The operation of the door lock required by current safety standards is obtained here by means of an architecture of the door lock which allows to simplify the architecture of the door lock itself, in particular by reducing the connecting contacts (10, 20) with the household appliance to only two.