Aircraft Stick Jack Reducing Pivot Bearing Seizing
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Solution Overview
Problem
Traditional piloting devices for vehicles, such as aircraft, are bulky, prone to seizing due to excessive pivot bearings, and have increased inertia and bulkiness from return elements, leading to reduced maneuverability and reliability.
Innovation Solution
A piloting device with a cradle and stick mounted on orthogonal pivot axes, featuring a stick jack arranged between the stick and frame, utilizing a spherical joint and tubular fluid dampers to minimize coupling and friction, and reduce the number of pivot bearings, with return means that exert forces based on displacement speed rather than position, allowing for compact, reliable, and flexible operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional piloting devices use multiple pivot bearings for mounting the piloting member, then the device achieves stable pivoting movement, but the number of pivot bearings increases leading to higher risk of seizing and increased device complexity
Solution Approach 1:
The patent extracts and eliminates unnecessary pivot bearings from the traditional configuration. By mounting the piloting member directly to the frame at the intersection point of orthogonal axes, the invention removes intermediate pivot joints and idler arms, reducing the number of pivot bearings from eight to a minimum necessary set, thereby reducing seizing risk while maintaining stable pivoting movement
Solution Approach 2:
The patent segments the return functions for the piloting member into separate return means that act independently on each axis. This segmentation allows each return mechanism to operate on a single pivot axis without interfering with the other, reducing coupling effects and simplifying the overall structure while maintaining reliable return functionality
2Ease of operation
If return elements are installed on the intermediate framework to return the piloting member to neutral position, then the piloting member can be returned to predetermined position, but the intermediate framework becomes bulkier and has increased inertia
Solution Approach 1:
The patent extracts the return elements from the intermediate framework and mounts them directly to the frame. This eliminates the need for an intermediate framework to support return mechanisms, allowing the framework to be simplified or eliminated entirely. The return elements now act directly on the piloting member mounted to the frame, reducing the framework's bulkiness and inertia while maintaining the return-to-neutral function
Solution Approach 2:
Instead of mounting return elements on the intermediate framework and having them act through it, the patent inverts the arrangement by mounting return elements directly to the frame and having them act directly on the piloting member. This inversion eliminates the intermediate framework's role as a support structure for return mechanisms, reducing its necessary mass and complexity
3Weight of moving object
If the piloting device uses a compact design with reduced pivot bearings, then the device becomes lighter and more maneuverable, but friction and clearances may increase leading to potential seizing
Solution Approach 1:
The patent applies local quality by concentrating the necessary pivot bearings at critical locations where they are most effective, rather than distributing them throughout intermediate structures. By mounting the piloting member directly to the frame at the axis intersection, the invention places pivot bearings only where absolutely necessary for the two-axis pivoting function, minimizing total number while ensuring proper lubrication and clearance management at each location
Solution Approach 2:
The patent implements self-service through the spherical joint design that automatically maintains proper clearance and lubrication distribution. The spherical joint's geometry allows for self-adjusting contact points that distribute loads evenly and maintain optimal clearance without requiring external adjustment mechanisms, reducing friction while maintaining reliability in the compact design
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 solution results in a lighter, more compact, and reliable piloting device with reduced friction and risk of seizing, improved maneuverability, and simplified maintenance, while maintaining precise control over pitch and roll movements.
Implementation Method 1
tubular fluid dampers to minimize coupling and friction
Implementation Method 2
spherical joint and tubular fluid dampers to minimize coupling and friction
Data Source
AI summary
A piloting device (1) for piloting a vehicle, in particular an aircraft, has a frame (10), a cradle (20) pivoting with respect to the frame on a first pivot axis (R), a piloting member, called a stick (30), pivoting with respect to the cradle (20) on a second axis (T) orthogonal to and intersecting the first axis, first return elements (11,11′,12) for returning the cradle to a predetermined position with respect to the frame, called the neutral position of the cradle, second return elements (21,21′,22) for returning the stick to a predetermined position with respect to the cradle, called the neutral position of the stick, wherein at least one of the second return elements, called a stick jack (22), is arranged between the stick and the frame.