French Door Linkage Coupling to Eliminate Backlash Lag
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Solution Overview
Problem
French door systems with interconnected doors suffer from backlash and space inefficiency due to complex gear or chain transmissions, leading to unsatisfactory operation and ergonomic issues.
Innovation Solution
A door coupling mechanism using ternary links pivotally or slidably mounted to a frame, allowing simultaneous operation of both doors through rotatable couplings, enhancing the feel and reducing lag during opening and closing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gear or chain transmissions are used to interconnect doors, then door operation is synchronized, but backlash occurs leading to unsatisfactory operation feel
Solution Approach 1:
The patent replaces traditional gear or chain transmission mechanisms with a parallel linkage system consisting of two independent door links connected to a common pivot point on the frame. This mechanical substitution eliminates backlash while maintaining synchronization through geometric constraints rather than toothed engagement, providing both smooth operation feel and reliable door coordination.
2Device complexity
If gear or chain transmissions are used to interconnect doors, then door operation is synchronized, but the transmission includes a significant number of parts and is space inefficient
Solution Approach 1:
The patent divides the door coupling function into two separate door links, each independently connected to its respective door and to a common pivot point. This segmentation allows each link to be a simple, minimal-component structure rather than a complex transmission assembly, reducing the total number of parts while maintaining synchronization through the shared pivot constraint.
Solution Approach 2:
The patent extracts and eliminates the intermediate transmission components (gears, chains, sprockets) that traditionally mediate between doors. By directly connecting each door to the common pivot through simple links, the design removes unnecessary parts while preserving the essential synchronization function through geometric relationship.
3Ease of operation
If two hands are used to open both doors simultaneously, then door operation is achieved, but ergonomics are compromised
Solution Approach 1:
The patent enables one-door-to-open-the-other-door functionality through the parallel linkage mechanism. When one door is pulled open, the mechanical connection through the door links and common pivot automatically drives the second door open as well, allowing a single user action to perform what would traditionally require two separate hand operations, thereby improving ergonomics while maintaining operational efficiency.
Data Source
AI summary
An apparatus including a frame forming an internal cavity, the frame having an opening for accessing the internal cavity, a first door and a second door mounted to the frame and a door coupling mechanism for effecting a substantially simultaneous movement of the first door and second door relative to the frame, the door coupling mechanism including a first door link, a second door link and at least one ternary link, the first door link being rotatably coupled to the first door and the at least one ternary link, the second door being rotatably coupled to the second door and the at least one ternary link.