Dual-Stroke Safety Switch for Washing Machine Eccentricity Control

Solution Overview

Problem

Traditional washing machine safety switches fail to effectively control the dewatering process and prevent severe vibration and noise due to uneven laundry distribution, leading to abrupt changes in rotation speed and increased water, power, and time consumption.

Innovation Solution

A dual-stroke safety switch with two motion strokes for the washing machine, featuring a control rod and two micro switches with different activation thresholds, allowing for precise control of the dewatering process and eccentricity correction by determining the degree of tub eccentricity and adjusting the rotation speed or suspending the process accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional single micro switch safety switch is used, then the structure is simple, but it cannot timely and effectively control the dewatering operation, leading to abrupt changes in rotation speed and increased water, power, and time consumption

Engineering Contradiction:

Improvesafety switch structureVSAvoiddewatering operation efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The single micro switch is segmented into two micro switches (first and second) with different motion stroke requirements. The control rod is divided into multiple segments that can independently actuate different switches at different displacement thresholds, enabling staged control responses without requiring a completely complex safety switch structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the motion stroke parameter of the control rod to selectively activate different micro switches. By adjusting the motion stroke distance, the system can differentiate between mild and severe eccentricity conditions, triggering appropriate control actions (deceleration vs. suspension) to maintain dewatering efficiency while preventing damage

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the dewatering process is suspended to correct load distribution, then the load distribution can be adjusted, but the rotation speed changes abruptly causing water, power, and time consumption issues

Engineering Contradiction:

Improveload distribution balanceVSAvoidpower and water consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system performs preliminary action by detecting eccentricity conditions in advance through the control rod's displacement and activating the first micro switch before severe imbalance occurs. This early detection allows for gradual deceleration and load redistribution rather than abrupt suspension, reducing energy waste and maintaining process continuity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dual micro switch system provides feedback about the degree of eccentricity to the control system. Based on which switch is activated (first, second, or both), the controller implements differentiated feedback control strategies - mild eccentricity triggers deceleration while severe eccentricity triggers suspension, optimizing the balance between load distribution correction and energy consumption

Inventive Principle:

Principle #23Feedback

3Reliability

If the dewatering process is suspended for eccentricity correction, then the load distribution can be adjusted, but the rotation speed changes abruptly causing severe vibration and big noise

Engineering Contradiction:

Improveload distribution balanceVSAvoidvibration and noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by detecting eccentricity conditions in advance through the control rod's displacement and activating the first micro switch before severe imbalance occurs. This early detection allows for gradual deceleration and load redistribution rather than abrupt suspension, reducing energy waste and maintaining process continuity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dual micro switch system provides feedback about the degree of eccentricity to the control system. Based on which switch is activated (first, second, or both), the controller implements differentiated feedback control strategies - mild eccentricity triggers deceleration while severe eccentricity triggers suspension, optimizing the balance between load distribution correction and energy consumption

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10450689B2Dual-stroke safety switch of washing machine and eccentricity control method

Publication Date: 2019.10.22 QINGDAO HAIER WASHING MASCH CO LTD

AI summary

A dual-stroke safety switch of a washing machine has a control switch mounted in a base, and a control rod movably connected to the base. The control switch comprises a first control switch and a second switch. The control rod has two motion strokes respectively for controlling the switch-off of the first control switch and the second switch, and the motion stroke for the switch-off of the first control switch is less than the motion stroke for the switch-off of the second control switch. The different strokes of the control rod substantially reflect different degrees of eccentricity of a water tub. The switch-off of the first control switch indicates that small eccentricity of the water tub takes place, and the switch-off of the second control switch indicates that there is serious eccentricity.