Aircraft Towbar Shock Assembly for Peak Force Damping
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Solution Overview
Problem
Existing towbars for aircraft lack effective damping mechanisms to manage the forces applied during towing, leading to high peak forces and potential damage to the aircraft and towing vehicles.
Innovation Solution
A towbar with a shock assembly that includes a first and second spring biasing mechanism and a fluid damper with a piston and orifices, which provides damping forces that resist movement and vary as a function of position and velocity, reducing peak forces and improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid towbar is used to connect the tow vehicle to the aircraft, then the structural strength is sufficient, but the peak forces during towing become excessively high causing potential damage
Solution Approach 1:
The patent incorporates a shock assembly with springs and dampers that provides beforehand cushioning by absorbing and dissipating impact forces before they can cause damage to the aircraft or tow vehicle. The springs compress to absorb energy during sudden force applications, while the dampers dissipate energy through fluid resistance, thereby reducing peak forces while maintaining structural integrity.
Solution Approach 2:
The shock assembly changes the mechanical parameters of the towbar system by introducing elastic (springs) and viscous (dampers) elements that modify the force transmission characteristics. These parameter changes allow the system to absorb and dissipate energy dynamically, transforming rigid force transmission into a more compliant system that reduces peak forces.
2Device complexity
If no damping mechanism is used in the towbar, then the device complexity is low, but the damping forces to resist movement are insufficient
Solution Approach 1:
The shock assembly acts as an intermediary mechanism between the tow vehicle and aircraft, introducing springs and dampers that mediate the force transmission. This intermediary layer absorbs and dissipates energy, providing necessary damping forces while adding only moderate complexity to the overall system.
Solution Approach 2:
The damper component utilizes hydraulic principles by employing fluid resistance through orifices to provide damping forces. The fluid viscosity and pressure differential created by piston movement generate resistive forces that dampen oscillations and reduce peak forces, leveraging pneumatic/hydraulic effects to achieve the desired damping performance.
3Device complexity
If the shock assembly provides constant damping force, then the control is simple, but the damping force does not vary with position and velocity reducing effectiveness
Solution Approach 1:
The shock assembly implements dynamics by providing damping forces that vary with position and velocity rather than remaining constant. The spring component provides position-dependent force (Hooke's law), while the damper provides velocity-dependent force through fluid resistance. This dynamic response allows the system to adapt to varying towing conditions, improving effectiveness across different operating states.
Solution Approach 2:
The damping characteristics are made parameter-changing by allowing the damping force to vary as a function of position (through spring compression) and velocity (through fluid resistance). This parameter change enables the shock assembly to provide appropriate damping levels for different towing scenarios, enhancing reliability and effectiveness.
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 shock assembly reduces peak forces by approximately half and provides a more controlled damping force, enhancing the safety and efficiency of the towing process.
Implementation Method 1
a first spring biasing the first and second structures away from each other
Implementation Method 2
a second spring biasing the first and second structures towards each other
Implementation Method 3
Movement of the piston in the first fluid chamber in a first direction causes fluid in the first portion of the first fluid chamber to be pressurized and flow out of the first portion of the first fluid chamber through at least one orifice and into the second fluid chamber
Implementation Method 4
a damper comprising a first fluid chamber and a second fluid chamber that is in fluid communication with a first fluid chamber through a plurality of spaced-apart orifices that restrict flow of fluid between the first fluid chamber and the second fluid chamber
Data Source
AI summary
A shock absorber for towbars provides damping forces that reduce forces when stopping and starting during towing operations of aircraft.