Laundry Dryer Door Locking Mechanism for Program-Controlled Opening
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Solution Overview
Problem
Current door locking devices in tumble dryers are mechanically actuated and cannot be opened under program control, requiring manual handles for door opening, which is undesirable for design and user-friendliness.
Innovation Solution
A door locking device comprising a rocker unit, lever unit, and actuator unit, where the rocker unit is rotated by a pawl and locking mandrel, and an electrically actuable actuator unit converts force into torque to open the door, allowing program-controlled unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a mechanical door locking device with rocker assembly is used, then the door can be kept closed during the drying program, but the door cannot be opened under program control
Solution Approach 1:
The patent replaces the purely mechanical door locking system with an electromechanical system. An actuator unit with electric motor is introduced to rotate the rocker unit, enabling program-controlled door opening without requiring manual handles. The control unit activates the actuator to rotate the rocker, which moves the locking mandrel to release the door.
Solution Approach 2:
The door locking device enables the door to open automatically without user intervention. The control unit autonomously activates the actuator unit at appropriate moments (e.g., at the end of the drying program), and the rockerspring provides automatic door closing assistance, making the system self-servicing.
2Extent of automation
If an actuator unit with electric motor is added to enable program-controlled opening, then automatic door opening is achieved, but the device complexity increases
Solution Approach 1:
The rocker unit serves multiple functions: it transmits torque from the actuator to control door opening, and simultaneously works with the rockerspring to enable automatic door closing. The locking mandrel also serves dual purposes by engaging with both the pawl for locking and being actuated by the rocker for unlocking.
Solution Approach 2:
The patent combines the actuating mechanism and the locking mechanism into a single integrated rocker unit. The actuator unit with electric motor is merged with the existing rocker assembly, allowing one component to handle both the opening and closing operations through its rotational movement.
3Device complexity
If the actuator unit applies force directly to the rocker, then the structure is simpler, but the actuator cannot overcome static friction in the lever unit
Solution Approach 1:
The lever unit is designed to provide a low-load initial travel path for the actuator. The lever arm pivots freely at first, allowing the actuator to overcome static friction in the lever unit's pivot joint before the locking mandrel begins to move. This preliminary movement prepares the system for the subsequent high-force phase.
Solution Approach 2:
The lever unit transitions from a static friction-dominated state to a dynamic movement state. As the actuator rotates the lever arm, the system dynamically shifts from overcoming static friction to moving the locking mandrel against the door spring force, optimizing the actuator's effectiveness throughout the operation.
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 automatic door opening after the drying program ends without the need for recessed grips or handles, enhancing design and user experience by allowing controlled operation.
Implementation Method 1
The door locking device preferably comprises a coil and a magnetizable armature (electric lifting magnet). Electrical activation of the door locking device or unlocking of the door is thus possible.
Implementation Method 2
A rocker spring exerts a torque M 2 on the rocker.
Data Source
Figure 1~3
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Figure 7~9
AI summary
The invention relates to a door locking device (1) that can be unlocked under program control and has a rocker unit (10) which comprises a rocker (11), a compression spring (12), a rotatable pawl (13) and a rocker stop (14). A locking pin (99) as a counterpart can engage in a groove (16) on the pawl (13) and, after a certain position has been exceeded, is pulled against the door locking device (1) by the compression spring (12) and held there in a position (P2). . The pawl (13) rotates. A lever unit (20) and an actuator unit (30), which exert a torque against the compression spring (12) on the rocker (11), are used for program-controlled unlocking. When a certain position is exceeded, the pawl (13) rotates back and releases the closing pin (99).