Variable Resistance Brake Caster for Load-Adaptive Braking
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Solution Overview
Problem
Existing cargo handling systems face issues with braking mechanisms that are too powerful for lighter loads, causing skidding and wear on the friction material, which can lead to safety risks and damage during loading and unloading of unit load devices (ULDs).
Innovation Solution
A brake mechanism incorporating a piezoelectric disk that adjusts rotational resistance based on applied voltage, allowing for variable braking force adjustment according to the weight of the load, using a roller cylinder, brake shaft, and unidirectional roller bearings to ensure effective braking without excessive wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preset braking load is selected for maximum weight of loaded ULD, then braking effectiveness for heavy loads is improved, but the braking load becomes too powerful to allow rotating element to roll under light loads
Solution Approach 1:
The braking load is made dynamically adjustable through a variable resistance mechanism that changes the braking force based on operating conditions. The system transitions from a static preset braking load to a dynamic braking load that adapts to the weight of the ULD being transported, allowing light loads to roll freely while maintaining effective braking for heavy loads.
Solution Approach 2:
The braking parameter (braking load) is changed from a fixed value to a variable value that can be adjusted according to the weight of the ULD. This parameter change enables the system to optimize braking force for different loading conditions, preventing both excessive braking on light loads and insufficient braking on heavy loads.
2Reliability
If friction material surrounds the outer surface of cylindrical roller, then braking capability is improved, but skidding and wear occur when braking load is too powerful for the applied load
Solution Approach 1:
The braking force applied through the friction material is made dynamic rather than static. By adjusting the braking load to match the applied load, the system prevents skidding conditions that cause wear while maintaining adequate braking capability when needed.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor operating conditions and adjust the braking load accordingly. This feedback control prevents the braking force from exceeding the applied load, thereby eliminating skidding and associated wear of the friction material.
3Reliability
If maximum braking load is used for safety, then protection of loading personnel and aircraft is improved, but damage to friction material and creation of flat spots on roller occurs
Solution Approach 1:
The braking parameter is changed from a maximum fixed value to a variable value that adjusts based on actual operating conditions. This parameter adjustment maintains safety by ensuring adequate braking force is available when needed while preventing excessive braking force that would cause premature wear and flat spots on the roller.
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 provides a customizable braking force that adapts to varying load weights, preventing skidding and wear, thereby enhancing safety and reducing damage to aircraft cargo compartments during cargo handling operations.
Implementation Method 1
the piezoelectric disk is configured to expand an axial distance with respect to the brake shaft upon a voltage difference being applied across a first conductor and a second conductor, the first conductor and the second conductor being electrically coupled to the piezoelectric disk
Data Source
AI summary
A brake mechanism for a brake caster is disclosed. In various embodiments, the brake mechanism includes a roller cylinder having a hollow interior and an inner cylindrical surface; a brake shaft disposed within the hollow interior of the roller cylinder and having an outer cylindrical surface; a piezoelectric disk disposed within the hollow interior of the roller cylinder; and a rotor disk disposed adjacent the piezoelectric disk.