Door Closure Mechanism with Opposed-Thread Actuator for Flush Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft air conditioning system exhaust doors with flush mounting require precise adjustment due to high manufacturing tolerances of materials like glass or carbon fibre, and are prone to failure if foreign objects obstruct the pivot arm, leading to complex closure mechanisms and incomplete sealing.
Innovation Solution
A door closure mechanism using opposed threaded portions with a universal joint and flexible stabilisers, allowing a single motor to efficiently raise and lower the door with minimal moving parts, accommodating misalignment and foreign objects through a ball-and-socket joint and flexible elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a door is mounted on a pivot arm with a rotary actuator to achieve flush mounting, then the door can be mounted substantially flush with the surrounding surface, but the mechanism becomes complicated due to high manufacturing tolerances requiring careful adjustment and shimming
Solution Approach 1:
The door closure mechanism is divided into separate functional segments: a linear actuator for primary door movement, a universal joint for alignment accommodation, and a seal mechanism for engagement. This segmentation allows each component to perform its specific function independently, eliminating the need for complex pivot arm assemblies and shimming procedures while maintaining flush mounting capability.
2Ease of operation
If a pivot arm mechanism is used for door closure, then the door can be actuated, but foreign objects lodged on the seat adjacent the pivot prevent the door from closing fully
Solution Approach 1:
A flexible seal element acts as an intermediary between the door and the seat, allowing the door to close completely even when foreign objects are present on the seat. The seal element deforms to accommodate obstacles while maintaining the sealing function, preventing foreign objects from blocking door closure.
3Strength
If materials like glass or carbon fibre are used for the surrounding structure, then aesthetic and structural requirements are met, but manufacturing tolerances are high requiring complicated adjustment procedures
Solution Approach 1:
The universal joint introduces dynamic adaptability to the door mounting system, allowing real-time adjustment of door alignment as it closes. This dynamic compensation mechanism accommodates the high manufacturing tolerances inherent in glass and carbon fibre structures without requiring precise pre-adjustment or shimming, while maintaining proper engagement with the seat.
4Device complexity
If a single motor with opposed threaded portions is used to raise and lower the door, then device complexity is reduced, but the mechanism must accommodate misalignment and foreign objects
Solution Approach 1:
The universal joint merges multiple functions into a single component: it accommodates misalignment between the actuator and door, allows rotation to navigate obstacles, and maintains connection throughout the motion range. This consolidation enables a simple single-motor opposed-threaded-portion actuator to achieve both complexity reduction and adaptability to manufacturing tolerances and foreign objects.
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
The mechanism simplifies door operation, maintains flush sealing, and accommodates manufacturing tolerances and foreign object interference, ensuring reliable and efficient closure with reduced complexity and cost.
Implementation Method 1
The universal joint may comprise a ball and socket. The ball may be coupled to the first and second drive linkages and the socket may be coupled to the door.
Implementation Method 2
The stabiliser may comprise at least one flexible element mounted between the universal joint and the door.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
There is provided a door mechanism comprising a door (20) and a door closure mechanism (22) for moving the door (20) between a first, open, position and second, closed position. The door closure mechanism (22) comprises a drive motor (32) coupled to a drive screw (34), the drive screw (34) having a first, right handed thread portion (56) and a second, left handed thread portion (58), a first drive nut (60) threadedly engaged with the first thread portion (56), a second drive nut (62) threadedly engaged with the second thread portion (58), a first drive linkage (70) pivotally coupled to the first drive nut (60) at one end (72) and to the door (20) at a second, opposed end (80), and a second drive linkage (76) pivotally coupled to the second drive nut (62) at one end (78) and to the door at a second, opposed end (80). Rotation of the drive motor (32) causes the first and second drive nuts (60, 62) in opposite directions along the drive screw (34) so as to raise or lower the door (20) relative to the drive screw (34).