Aircraft Hatch Locking Sleeve for Self-Centering Under Tensile Load
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Solution Overview
Problem
Pivot-and-slide or rotary pivot doors in aircraft face challenges with high tensile forces and load differences, leading to deformations and misalignment of hatch locking elements, which impair the sealing and locking mechanisms.
Innovation Solution
A hatch locking device featuring an eccentric bush, conical pressing and clamping sleeves, and linear actuators that actively dissipate tensile forces into the hatch frame, ensuring self-centering and reliable locking with hydraulic actuation, and coatings to reduce friction for self-locking action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locking mechanisms are used in aircraft hatches, then the structure is simple, but high tensile forces cause deformations and misalignment of locking elements
Solution Approach 1:
The locking mechanism transitions from a static system to a dynamic one where the clamping sleeve can actively adjust its position along the bolt axis. The conical pressing sleeve enables dynamic clamping force application, allowing the system to compensate for deformations caused by high tensile forces during flight, thereby maintaining reliable locking despite structural changes.
Solution Approach 2:
The system changes the clamping parameter dynamically by moving the clamping sleeve along the bolt axis. This parameter change allows the locking mechanism to adapt to varying tensile forces and maintain proper alignment precision throughout operation, resolving the contradiction between reliability under load and manufacturing precision.
2Strength
If larger locking components are used to handle high tensile forces, then the locking strength increases, but the installation space requirement increases
Solution Approach 1:
The clamping sleeve is nested within the bolt receptacle, and the conical pressing sleeve is nested within the clamping sleeve. This nested arrangement allows the locking mechanism to achieve high locking strength through active clamping while occupying minimal installation space within the hatch structure, effectively resolving the contradiction between strength and volume.
Solution Approach 2:
The solution moves from a two-dimensional locking interface to a three-dimensional active clamping system. The clamping sleeve can move along the bolt axis (adding a dimensional degree of freedom), enabling high locking strength through axial clamping force while maintaining compact radial dimensions for space efficiency.
3Productivity
If manual locking procedures are used, then the device complexity is low, but the operation time and labor requirements increase
Solution Approach 1:
The system uses a conical pressing sleeve that can be actuated by hydraulic or pneumatic pressure to generate the clamping force. This allows automated actuation of the locking mechanism, significantly increasing locking speed and productivity while the hydraulic/pneumatic system provides a manageable level of complexity through well-established technology.
Solution Approach 2:
The conical geometry of the pressing sleeve creates a self-amplifying mechanism where applied pressure automatically generates the necessary clamping force without requiring complex control systems. The system serves itself by converting pressure into mechanical clamping action, improving productivity while keeping device complexity moderate.
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
Effectively transmits forces and torques, compensates for manufacturing tolerances, and enhances the reliability of the locking mechanism by dissipating high tensile loads into the bulkhead structure, ensuring secure and self-centering closure.
Implementation Method 1
coatings to reduce friction for self-locking action
Implementation Method 2
linear actuators which are mounted on in each case two opposite sides of the conical pressing sleeve in the inner lining and are designed to displace the conical pressing sleeve along the bolt receptacle axis
Data Source
AI summary
A hatch locking device for an aircraft hatch includes an eccentric bush which can be connected to a hatch bulkhead of the aircraft hatch panel, an inner lining which is introduced into the eccentric bush and has a bolt receptacle which is oriented centrally along a bolt receptacle axis for receiving a locking bolt, a conical pressing sleeve in the inner lining, a conical clamping sleeve, the outer conical shell face of which is in displaceable engagement with an inner conical shell face of the conical pressing sleeve, and the inner cylindrical shell face of which is flush with the outer wall of the bolt receptacle, and linear actuators which are mounted on in each case two opposite sides of the conical pressing sleeve in the inner lining and are designed to displace the conical pressing sleeve along the bolt receptacle axis with respect to the conical clamping sleeve.