Motorized Cam Door Opening for Low-Force Appliance Latching
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Solution Overview
Problem
Conventional domestic appliances with mechanical door opening mechanisms require significant user effort, are unsuitable for disabled or frail individuals, and lack automatic or remote-controlled door opening capabilities, especially after cooking is finished, leading to issues with food moisture retention and cosmetic design.
Innovation Solution
A controllable door opening mechanism using a rotary motor, cam system, and resilient members to open the door with minimal user effort, enabling automatic or remote operation, and allowing for a handle-free design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical latch or door lock is used in conventional appliances, then the door can be securely closed and locked, but the user must apply considerable force to release the latch or door lock, making it problematic for disabled and frail users
Solution Approach 1:
The patent replaces the conventional mechanical latch release mechanism with an electromechanical actuator that can be controlled by a microprocessor. The actuator uses electrical power to automatically release the door latch, eliminating the need for users to apply considerable manual force to mechanical levers or buttons. This substitution directly addresses the contradiction by maintaining secure door closure while enabling easy, low-force opening through automated electronic control.
Solution Approach 2:
The system enables the door opening function to serve itself through automated control. The microprocessor monitors cooking completion and automatically triggers the actuator to release the latch at predetermined times, making the door opening process self-initiated without requiring user physical effort. This resolves the contradiction by making the door opening service automatic rather than manually effort-intensive.
2Ease of operation
If a handle or large mechanical push button is used for door opening, then the door can be opened mechanically, but it is considered unsightly from a cosmetic point of view
Solution Approach 1:
The patent replaces visible mechanical door opening components (handles, large push buttons) with an electromechanical actuator system controlled by a microprocessor. The actuator can be integrated into the appliance structure with minimal visible elements, such as a small button or touch-sensitive area on the control panel. This substitution maintains full door opening capability while dramatically improving cosmetic appearance by eliminating bulky mechanical components.
3Productivity
If the door remains closed after cooking is finished, then the appliance maintains a closed position, but hot steaming food remains trapped causing moisture buildup and potential safety issues
Solution Approach 1:
The system uses feedback from the microprocessor to monitor cooking completion status and automatically control the door opening timing. After cooking finishes, the microprocessor waits for a predetermined time delay to allow food to settle, then automatically triggers the actuator to open the door. This feedback-controlled timing resolves the contradiction by maintaining door closure during cooking for efficiency while automatically opening afterward to prevent moisture buildup and safety issues.
Solution Approach 2:
The system performs preliminary action by pre-programming the door opening sequence. The microprocessor is configured with predetermined time delays that automatically initiate door opening at the optimal moment after cooking completion. This preliminary programming ensures that the door opens at the precise moment needed to prevent moisture buildup, resolving the contradiction between maintaining closure for cooking efficiency and opening to prevent harmful moisture accumulation.
4Extent of automation
If automatic door opening is implemented, then the door can open without user presence, but the mechanism requires additional components such as motors and control systems
Solution Approach 1:
The patent integrates the door opening actuator into the existing appliance control system, allowing the same microprocessor and control infrastructure to serve multiple functions: monitoring cooking, controlling heating elements, and managing door opening. The actuator itself is a compact electromechanical component that can be integrated into the existing latch mechanism. This multi-functionality approach resolves the contradiction by achieving automatic door opening without proportionally increasing overall system complexity, as the control architecture serves multiple purposes.
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
Facilitates easy door opening with reduced manual force, automatic operation after cooking, and a sleek design, improving usability for all users and reducing moisture buildup in appliances.
Implementation Method 1
a resilient member, for urging the door open
Implementation Method 2
a cam, the cam having a plurality of cam surfaces, each cam surface being adapted to move the retention mechanism out of said first configuration through camming action
Data Source
Figure 1(a)~2
Figure 3(a)
Figure 3(b)
AI summary
A door opening mechanism for a domestic appliance (for example, a microwave oven), the domestic appliance including a housing, a front door, and a resilient member (e.g. spring bias), for urging the door open, wherein the door opening mechanism is adapted to be located within the housing; the door opening mechanism comprising: a retention mechanism, engageable with the door and movable between a first configuration, in which the door is retained in a closed position, and a second configuration, in which the door is non-engaged; a cam, the cam having a plurality of cam surfaces, each being adapted to move the retention mechanism out of said first configuration through camming action; and a rotary motor, for driving the cam in response to control signals. The cam suitably comprises a plurality of equally angularly spaced projections, the outer surfaces of the cam between successive projections comprising a cam surface. Suitably, each cam surface comprises of two slopes, one for clockwise cam motion and the other for anticlockwise cam motion, both cooperating with the retention mechanism as it moves from the first configuration to the second configuration, thus opening the door. This allows for a directional or multi-directional camming action. Each cam surface may comprise a first part, for cooperating with the retention mechanism as it moves into the first configuration, and a second part, for cooperating with the retention mechanism as it moves from the first configuration to the second configuration. In use, the cam moves a rotatable member into a position such that the spring biasing element acts on the door such that the door rotates to the partially open position. The rotatable member has a guide surface, the guide surface including a transition point and being disposed such that, in use, a key member attached to the door is capable of sliding contact with the rotatable member along the guide surface; wherein, after the key member has slid beyond the transition point, forces due to gravity and to the spring biasing element operate on the door such that the door rotates to the partially open position. Also disclosed is a domestic appliance, comprising: a housing, a front door, the door opening mechanism, a resilient member (e.g. spring bias), for urging the door open, and controller, coupled to the motor, the controller being operable in response to one or more signals to activate the motor, and thereby cause the door to move open.