Door-Opening Actuator Pulse Control for Reduced Mechanical Stress
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Solution Overview
Problem
Existing door opening devices in household appliances face limitations in safety and convenience due to restricted adjustable time characteristics of the opening force, leading to potential injury from violent door opening and inability to fine-adjust for voltage fluctuations, especially with AC drives which require rapid energy delivery and result in vibration and mechanical stress.
Innovation Solution
A method and device utilizing an electromechanical actuator with a magnetic coil and a movable magnetizable actuator element, generating a pressing force with a rising envelope time profile through a pulsed coupling signal, and incorporating a variable resistance element like a thermistor to manage energy delivery and reduce vibration, allowing for safer and more controlled door opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AC voltage is used to power the electromechanical actuator, then the door opening device can operate with standard power supply, but the opening force cannot be fine-adjusted and causes violent door opening
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to deliver energy to the actuator in controlled pulses rather than continuous AC power. The control unit generates periodic control signals that switch the actuator on and off at specific duty cycles, enabling precise control of the opening force while maintaining compatibility with AC power supplies. This resolves the contradiction by allowing standard voltage input while achieving fine-adjustable door opening control.
2Productivity
If rapid energy delivery is used to overcome frictional connection, then the door can be opened quickly, but mechanical stress and vibration increase
Solution Approach 1:
The patent applies dynamics by transitioning from static friction overcoming to dynamic controlled motion. The control unit dynamically adjusts the duty cycle of PWM signals based on the door's position and resistance, delivering rapid energy bursts when needed while reducing power during smoother phases of opening. This enables quick door opening while minimizing mechanical stress and vibration through adaptive energy delivery.
3Reliability
If high force is applied to overcome locking device, then the door opens reliably, but user safety is compromised
Solution Approach 1:
The patent applies preliminary action by using the actuator to gradually build momentum and overcome the locking device's frictional connection before the door fully opens. The control unit monitors the door's movement and adjusts energy delivery in advance to ensure smooth transitions, preventing sudden releases that could injure users. This maintains reliable door opening while enhancing user safety through controlled, progressive force application.
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
The solution enhances safety and convenience by preventing violent door opening and enabling precise control of the opening force, reducing mechanical stress and noise, and ensuring consistent operation across varying voltage levels, thus improving user safety and appliance durability.
Implementation Method 1
an electromechanical actuator (11), in particular with a magnetic coil and a movable actuator element made of a magnetic or magnetizable material, which can be controlled in such a way that a magnetic force can be exerted on the movable actuator element
Implementation Method 2
incorporating a variable resistance element like a thermistor to manage energy delivery
Data Source
Figure 1
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Figure 4
AI summary
The invention relates to a method for controlling a door-opening device (10) of a domestic appliance (1) comprising a door (2) during an opening operation, said door-opening device comprising an electromechanical actuator (11), wherein the actuator (11) comprises two actuator connections (14, 15) for electrical control, by: providing a supply voltage (18) between an electrical supply connection (16) and an electrical reference connection (17) of the door-opening device (10), which supply voltage has a voltage form that is defined in a proper operating state of the domestic appliance (1), providing an electrical coupling device (13) for coupling a first of the two actuator connections (14, 15) to the supply connection (16) and/or a second of the two actuator connections (14, 15) to the reference connection (17) as needed, coupling the supply voltage (18) and the two actuator connections (14, 15) by means of the coupling device (13) in accordance with a pulsed coupling signal (19) for the electrical control of the actuator (11), producing a push-open force for action on the door (2) in accordance with the electrical control of the actuator (11), and producing the pulsed coupling signal (19) in accordance with the defined voltage form and/or in accordance with the provided coupling device (13) in order to achieve a time curve of the push-open force that has a rising envelope.