Door-locking device with safety system
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Solution Overview
Problem
Existing door-locking devices for household appliances are not entirely safe due to complexity and potential incorrect signal generation from multiple positions of the blocking element, leading to risks of activating appliances with the door open during sensor malfunctions.
Innovation Solution
A door-locking device with a simplified mechanism featuring an actuator, blocking member, switch, and detecting member, where the blocking member can assume a rest and engagement position, and the detecting member's position relative to the blocking member determines whether the switch is enabled or disabled, using a rocker arm and pushing spring to ensure accurate door state detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single blocking member with three different positions is used to detect door state, then the door-locking device can provide multiple signals, but the system becomes complex and prone to incorrect signal generation due to managing activation tolerances of three different positions
Solution Approach 1:
The blocking member is divided into two separate components: a blocking element with two positions (engaged/disengaged) and a detecting element with two positions (first position/second position). This segmentation simplifies the system by eliminating the need to manage three different positions and their associated activation tolerances, while still providing the necessary door state detection capability.
Solution Approach 2:
A detecting member acts as an intermediary between the blocking member and the switch. The detecting member translates the physical state of the door (open/closed) into a reliable electrical signal by mechanically interfering with or not interfering with the switch, thereby eliminating the need for complex tolerance management in the original sensor system.
2Loss of information
If a single blocking member with three different positions is used, then multiple signals can be generated, but the risk of incorrect signals increases due to activation tolerance management difficulties
Solution Approach 1:
The detection function is extracted from the blocking member itself and assigned to a separate detecting member. This extraction allows the blocking member to focus solely on its mechanical function (holding the door closed) while the detecting member independently provides reliable door state information, eliminating the risk of incorrect signals from tolerance management issues.
Solution Approach 2:
The detecting member provides direct mechanical feedback to the switch through interference or non-interference, creating a fail-safe system where the door state is reliably communicated. This feedback mechanism ensures that the control system receives accurate information about door status without being subject to tolerance accumulation errors.
3Measurement precision
If a complex system with three positions is used, then door state detection is possible, but the tolerance chain becomes complicated and difficult to manage
Solution Approach 1:
The system is segmented into distinct functional elements with clearly defined two-position states each. The blocking member handles mechanical engagement while the detecting member handles signal generation, with each element having simple binary states that eliminate complex tolerance chains while maintaining precise door state detection.
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 provides a reliable and safer method for detecting the door's open or closed state, preventing appliance activation when the door is open, even in case of sensor malfunction, by simplifying the tolerance chain and ensuring accurate signal management.
Implementation Method 1
a pushing spring, arranged so that when said blocking member is in said rest position, said pushing spring is compressed; while, when said blocking member is in said engagement position, said pushing spring exerts a force on said second end of said rocker arm
Data Source
AI summary
The present invention relates to a Door-locking device (1) for a household appliance, said household appliance being of the type comprising a door (5), said door-locking device (1) comprising an actuator (2), a blocking member (4), driven by said actuator (2), said blocking member (4) being capable of assuming a rest position and an engagement position, in which, when said door (5) is closed, said blocking member (4) engages with said door (5) holding it closed, and a switch (7), capable of assuming a first state, in which it enables the power supply to said household appliance, and a second state, in which it disables the power supply of said household appliance, characterized in that it comprises an activating assembly (3), coupled with said blocking member (4), and in that it comprises a detecting member (6) for detecting the position said door (5), movable of a relative motion with respect to said blocking member (4) of the door (5), so as to assume with respect to said blocking member (4) a first position, wherein, when said blocking member (4) is in said engagement position, said activating assembly (3) interferes with said switch (7), which assumes said first state; and a second position, wherein, when said blocking member (4) is in said engagement position and said door (5) of said household appliance is open, said activating member (31) does not interfere with said switch (7) that assumes said second state.