Motorized Appliance Latch for Low-Force Door Closure
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Solution Overview
Problem
Existing latching mechanisms for household appliances require significant force to open and close doors, especially as door gaskets age and become less compliant, leading to increased friction and closure forces.
Innovation Solution
A motorized latch mechanism with a spring-biased strike grip and low-profile design, utilizing a DC motor and gear train to apply high compressive forces with minimal user effort, allowing for easy door operation and accommodation of gasket compliance changes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a latch mechanism uses a spring mechanism to store energy during door opening, then the door can be pulled fully closed automatically, but a significant amount of force is required to open the door to compress the spring
Solution Approach 1:
The patent replaces the traditional mechanical spring-based over-center latch mechanism with a motorized actuator system. The motorized latch uses an electric motor to provide the closing force, eliminating the need for users to compress high-force springs during door opening. This substitution of mechanical spring energy storage with electrical motor actuation directly resolves the contradiction by maintaining automatic door closure while dramatically reducing the force required to open the door.
Solution Approach 2:
The patent introduces a motorized actuator as an intermediary between the user's opening action and the latch mechanism. Instead of directly compressing springs or overcoming mechanical resistance, the user's input is transmitted to a motor controller that manages the motor's operation. This intermediary system allows the door to be opened with minimal force while the motor provides the necessary force for secure latching and gasket compression.
2Reliability
If a latch mechanism uses high spring compression forces to ensure secure door closure, then the door can be held firmly closed, but substantial closing force is required to actuate the mechanism against friction
Solution Approach 1:
The patent replaces the mechanical spring compression system with a motorized actuator that provides controlled closing force. The motor can generate high forces when needed to compress the gasket and secure the door, while using minimal force during normal operation. This eliminates the need for users to apply substantial closing force against friction, as the motor handles all force requirements for secure door holding.
Solution Approach 2:
The patent employs a dynamic motorized system that can adjust its output force based on operational requirements. During door closure, the motor provides high force to overcome friction and compress the gasket. During door holding, the motor maintains only the necessary force to keep the door secured. This dynamic force adjustment resolves the contradiction by providing high reliability when needed while minimizing the force required during normal operation.
3Force
If a latch mechanism uses a lever operated by the user to engage a catch and draw the catch inward, then the gasket can be compressed with lever advantage, but the mechanism becomes more complex and requires more user effort
Solution Approach 1:
The patent replaces the manual lever-operated catch mechanism with a motorized actuator system. The motor directly drives the latching and gasket compression actions through a simplified mechanical linkage, eliminating the need for user-operated levers and complex catch mechanisms. This substitution maintains the ability to generate high gasket compression forces while dramatically reducing device complexity and user effort requirements.
4Ease of manufacture
If a latch mechanism is designed with low profile and injection molded thermoplastic construction, then the device becomes more compact and easier to manufacture, but the materials and size constraints may limit the force generation capability
Solution Approach 1:
The patent uses a motorized actuator to generate high compressive forces within a compact, low-profile housing constructed from injection molded thermoplastic. The motor provides the necessary force multiplication, allowing the use of lighter, easier-to-manufacture thermoplastic materials instead of heavy metals. This resolves the contradiction by enabling high force generation capability within a compact, easily manufactured design using modern materials and electrical actuation.
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
Enables door opening and closing with very low force, ensuring the door is securely held closed with reduced friction and stress on the latch components, accommodating gasket aging and compliance variations.
Implementation Method 1
a latch spring is compressed (energized) when the door is opened and this energy is released when the door is closed, assisting the user in compressing the door gasket
Implementation Method 2
a motorized latch mechanism with a spring-biased strike grip and low-profile design, utilizing a DC motor and gear train to apply high compressive forces
Implementation Method 3
utilizing a DC motor and gear train to apply high compressive forces with minimal user effort
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A motorized appliance latch provides for a spring-biased strike grip that can be engaged and disengaged from the strike with low force but then locked in a close position during closing of the door to allow the strike to be retained against countervailing gasket compression forces. In this way, an arbitrarily low force may be required by the consumer to close or open the door when the door is unsealed by the motor.