Door Lock Hook Sensing Mechanism for Fail-Safe Appliance Operation
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Solution Overview
Problem
Existing door-lock systems for household appliances can operate with the door open if the electronic circuit malfunctions, posing a safety risk as they fail to ensure proper engagement of the door hook, potentially leading to unsafe operation.
Innovation Solution
A door-lock system with a hook sensing mechanism that includes a shaft with radial arms and a hook sensing pin, which ensures the main switch remains open unless the door hook is correctly engaged, independent of the electronic circuit's functionality, using a mechanism that directly interacts with the main switch to prevent appliance startup when the door is open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electronic circuit controls the door sensing switch to prevent appliance operation when the door is open, then the appliance can be controlled to operate only when properly locked, but the system fails to ensure safety when the electronic circuit malfunctions
Solution Approach 1:
The patent replaces the electronic control system with a direct mechanical linkage system. The cam mechanism is mechanically coupled to the main switch through a linkage that directly opens the switch when the cam rotates to the unlocked position. This mechanical substitution eliminates dependency on electronic circuits, providing fail-safe operation where the appliance cannot start unless the door is properly locked, regardless of electronic circuit functionality.
2Ease of operation
If the main switch is controlled through an electronic circuit that reads the door sensing switch, then the appliance operation can be controlled, but the system allows operation with door open when electronic circuit malfunctions
Solution Approach 1:
The patent segments the control function into two independent parts: the door locking status detection (cam position) and the main switch control. The mechanical linkage directly connects these segments, creating an independent safety pathway that does not rely on the electronic circuit. This segmentation ensures that even if the electronic control portion fails, the mechanical segment continues to prevent operation when the door is open.
3Reliability
If a hook sensing mechanism detects door hook engagement, then the appliance can prevent startup when door is open, but the system still relies on electronic circuit functionality for safety
Solution Approach 1:
The patent merges the door engagement detection function and the main switch control function into a single integrated mechanical system. The cam mechanism that detects door hook engagement is directly linked through mechanical components to the main switch, combining detection and control in one unified mechanical pathway. This eliminates the need for separate electronic sensing and control circuits, providing inherent safety through the mechanical design itself.
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
Ensures the appliance can only start when the door is securely locked, providing enhanced safety by preventing operation with an open door even in case of electronic circuit failures, thereby addressing the safety concerns of malfunctioning systems.
Implementation Method 1
The door-lock comprises an electromagnet which controls a locking pin
Data Source
AI summary
A door-lock for household appliances, comprising:a casing having an opening through which it is intended to be inserted a hook connected to the door of the appliance,a cam articulated to the casing and rotatable between an open door position and a closed door position, wherein the insertion of the hook in the casing rotates the cam from the open door position to the closed door position,a locking mechanism including a locking pin movable between an unlocking position and a locking position,a main switch switchable between an open position and a closed position, wherein said locking pin in the unlocking position prevents the closure of the main switch, anda hook sensing mechanism including a hook sensing pin movable between a disengaged hook position and an inserted hook position, wherein said hook sensing pin cooperates directly with said main switch and prevents the closure of the main switch in the disengaged hook position.