Rotary Door Latch Locking Against Release and Yielding Motion
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Solution Overview
Problem
Existing door latches for domestic appliances, such as washing machines and ovens, face challenges in ensuring the door remains closed during operation due to the possibility of translational yielding movements, which can compromise the locking mechanism's effectiveness in preventing door opening.
Innovation Solution
A door latch with a rotary gripper that transitions from a release to a gripping position, incorporating an electrically controllable locking mechanism with a blocking element to prevent rotation and yielding movements, ensuring the door remains locked by blocking the rotary gripper's movement from both release and gripping positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotary gripper is allowed to have a yielding movement via translation in the rotational plane (as enabled by the elongate hole and pin arrangement), then the door can be closed properly, but the locking mechanism cannot ensure complete certainty against door opening during operation
Solution Approach 1:
The locking mechanism is segmented into two independent blocking functions: a first blocking element that prevents rotation from gripping position to release position, and a second blocking element that prevents translation from gripping position to yielding position. This segmentation allows each blocking element to address a specific movement mode, ensuring complete locking certainty while maintaining the yielding movement capability for proper door closing.
Solution Approach 2:
The rotary gripper is designed with dynamic characteristics, allowing it to perform both rotational movement (for latching) and translational yielding movement (for self-adjustment during door closing). The elongate hole and pin arrangement enable this dynamic behavior, while the blocking elements are designed to constrain only the gripping-to-release rotation and gripping-to-yielding translation, not the yielding movement itself.
2Reliability
If a blocking mechanism is introduced to prevent rotation of the rotary gripper, then the door can be locked during operation, but the translational yielding movement capability is compromised
Solution Approach 1:
The blocking elements are designed with local quality - each blocking element has a specific geometric configuration that targets a particular movement mode. The first blocking element's blocking surface is oriented to prevent rotation, while the second blocking element's blocking surface is oriented to prevent translation. This local specialization allows the locking mechanism to prevent unwanted movements while preserving the yielding movement capability needed for proper door closing.
Solution Approach 2:
The rotary gripper maintains its dynamic characteristics by allowing the pin to move within the elongate hole during yielding movement. The blocking elements are designed to constrain specific dynamic movements (rotation from gripping position, translation from gripping position) while permitting the necessary yielding movement for door closing, thus preserving adaptability while ensuring reliability.
Data Source
AI summary
A door latch for a domestic electrical appliance wherein the door latch comprises a rotary gripper which, on closing of a door, can be transferred from a release position into a gripping position by rotation in a rotational plane, and an electrically controllable locking mechanism having a movably arranged blocking element which, in the gripping position of the rotary gripper, can be fixed in a blocking position in which the blocking element cooperates with the rotary gripper to block the movement of the rotary gripper both from the gripping position into the release position and from the gripping position into a yielding position. The rotary gripper forms a gripping mouth which in the gripping position is oriented to hold captive a closing shackle which, on closing of the door, moves relatively closer to the rotary gripper along a closing path and arranged for a yielding movement into the yielding position.