Hook Detection Door Lock to Prevent False Closed Signals
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Solution Overview
Problem
Existing door-lock systems for household appliances continue to send electrical pulses to the electromagnetic actuator and provide incorrect closed door signals in abnormal conditions, leading to noise and heating issues, even when the appliance door is compromised or improperly assembled.
Innovation Solution
The door-lock system incorporates a safety feature with a bistable spring mechanism and a safety portion on the hook sensing slider that prevents the door sensing slider from moving to the closed position in abnormal conditions, ensuring the door detection switch remains open and no electrical pulses are sent to the actuator, thereby preventing unauthorized operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the locking slider is allowed to move freely to detect door position, then the door detection circuit can provide accurate open/closed door signals, but in abnormal conditions the locking slider may move to incorrect positions causing false closed door signals and continuous actuator pulsing
Solution Approach 1:
A safety portion is introduced as an intermediary element between the locking slider and the electromagnetic actuator. This safety portion acts as a mediator that physically blocks the locking slider from reaching positions that would cause false door closed signals or continuous actuator pulsing in abnormal conditions, while allowing normal operation when the door is properly assembled.
Solution Approach 2:
The safety portion is designed to automatically prevent incorrect operation without requiring external intervention. When the casing is dismantled or compromised, the safety portion passively blocks the locking slider's movement, causing the door detection circuit to naturally provide an open door signal and preventing continuous actuator pulsing, thereby making the system self-protecting.
2Reliability
If the locking pin is continuously actuated by electrical pulses, then the locking mechanism remains engaged, but in abnormal conditions this causes noise and heating of the actuator
Solution Approach 1:
The safety portion serves as a mechanical intermediary that interrupts the transmission of electrical pulses to the electromagnetic actuator in abnormal conditions. By physically blocking the locking slider from reaching positions that would complete the electrical circuit to the actuator, the safety portion prevents continuous actuation and its associated noise and heating problems.
Solution Approach 2:
The safety portion converts the potential harm of continuous actuator pulsing into a beneficial state by using the physical blockage to naturally open the door detection circuit. This transforms what would be a harmful continuous operation into a protective idle state, where the actuator remains inactive and the system generates no noise or excessive heat.
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 solution effectively prevents unauthorized operation and reduces noise and heating issues by maintaining the door detection switch in an open state during abnormal conditions, ensuring the appliance door remains securely open and preventing electrical actuation in compromised states.
Implementation Method 1
The door-lock system incorporates a safety feature with a bistable spring mechanism and a safety portion on the hook sensing slider
Implementation Method 2
an electromagnetic actuator comprising a locking pin to lock said locking slider in the lock position
Data Source
AI summary
A door-lock for household appliances, comprising a casing (12) having an opening (14) for the insertion of a hook (15) carried by a door of a household appliance, a cam (16) rotatable between a retaining position and a release position, a locking slider (20) cooperating with said cam (16) and movable between an unlocking position and a locking position, wherein in the locking position the locking slider (20) locks the cam (16) in the retaining position, an electro-magnetic device comprising a housing (70) and a locking pin (28) for locking the locking slider (20) in the locking position, a door sensing slider (32) movable between an open door position and a closed door position, and a hook sensing slider (74) movable between an extracted position and a retracted position, wherein the hook sensing slider (74) has a projection (82) that prevents the movement of the door sensing slider (32) from the open door position towards the closed door position when the hook sensing slider (74) is in the extracted position, wherein the hook sensing slider (74) has a safety portion (86) that, in an abnormal condition in which the integrity of the cam support (11) is compromised, comes into contact with a side (94) of the housing (70) and prevents movement of the hook sensing slider (74) from the extracted position towards the retracted position.