Washing Machine Door Lock Using DC Electromagnet Release
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Solution Overview
Problem
Existing safety locks for household appliance doors, such as washing machines, do not allow immediate door opening after the washing process is completed, and are prone to functional disruptions due to defects in electric or electronic elements, which can cause delays and increase production costs.
Innovation Solution
A safety lock utilizing a DC electromagnet with permanent magnets, where the programme selection switch controls the polarisation of the electromagnet core, ensuring immediate door opening after the washing process and maintaining functionality even with power interruptions, by using a sliding contact mechanism that allows the door to open when the switch is open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bimetal switch is used to control the door lock, then the door can be locked during operation, but the door cannot be opened immediately after operation completes due to slow cooling of the bimetal
Solution Approach 1:
The patent replaces the bimetallic strip (thermal-mechanical system) with a DC electromagnet controlled by a programme selection switch (electrical control system). The electromagnet can be de-energized instantly when the washing cycle completes, allowing the door lock to release immediately without the cooling delay inherent in bimetallic strips. This substitution of control mechanism eliminates the time loss while maintaining reliable locking during operation.
2Extent of automation
If electric or electronic elements are used in the lock, then the door can be controlled automatically, but defects in these elements can cause functional disruptions
Solution Approach 1:
The patent incorporates a mechanical assembly with a slider and spring that provides passive mechanical support for the door locking function. This mechanical backup ensures that even if the DC electromagnet or programme selection switch fails, the door can still be locked mechanically. The mechanical assembly acts as a cushion against total system failure, maintaining basic functionality despite electrical component defects.
3Reliability
If a mechanical assembly with slider is used, then the door lock can be mechanically secured, but the complexity of the device increases
Solution Approach 1:
The patent merges the electrical control system (DC electromagnet, programme selection switch) with the mechanical locking assembly (slider, spring, hook) into a single integrated door lock mechanism. The electrical components control the position of the electromagnet core, which directly actuates the slider to engage or disengage the mechanical lock. This integration allows the system to achieve reliable mechanical security without requiring separate independent mechanisms, thereby limiting the increase in complexity.
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 immediate door opening after the washing process without waiting for the bimetal to cool, ensuring the safety lock's functionality is preserved even with defects, reducing production costs and enhancing user convenience.
Implementation Method 1
a switch controlled by a DC electromagnet, the core of which engages with permanent magnets
Implementation Method 2
the core of which engages with permanent magnets
Data Source
AI summary
A safety lock for a door of a household appliance, preferably of a washing machine, includes a housing on one end of which there is a mechanical assembly of the door lock, on the other end there is an assembly of the electric switch used to reach closed or interrupted electric circuit, into which also a part of a programme selection switch is included, whereby the assembly of the door lock and the assembly of the electric switch are mutually linked by a slider, which is designed in a way that its lug engages with the hook of the appliance door, when the hook is in the guide, so that upon manual closing of the appliance door the hook pushes the slider towards the assembly when entering the guide.