Curved Arm Tank Car Lifter for Safe Single-Crane Recovery
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Solution Overview
Problem
Current methods for lifting railroad tank cars are inefficient and often damage the cars due to the need for heavy rigging and unstable lifting conditions, requiring multiple cranes and posing safety risks, especially when the cars are derailed or at an angle.
Innovation Solution
A tank car lifting apparatus that includes a beam attached to a crane, synchronized arms that extend around the tank car to lift it from below its center of gravity, and a storage system for efficient transport and storage, allowing for single-crane operation and minimizing contact with the tank car's jacket.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional rigging methods are used to lift tank cars, then the tank car can be lifted, but the rigging presses onto the tank car jacket and often damages it
Solution Approach 1:
The patent introduces an intermediary device (the lifting apparatus with curved arms) that mediates between the crane and the tank car. The curved arms extend around the tank car jacket to contact the lifting lugs, distributing the lifting force over a larger area and avoiding concentrated pressure points that would damage the jacket.
Solution Approach 2:
The lifting apparatus employs curved arms that follow the cylindrical contour of the tank car. This curvature allows the arms to wrap around the tank car jacket smoothly, maintaining contact with the jacket only where necessary for structural support while reaching the lifting lugs, thereby preventing damage to the jacket surface.
2Object-affected harmful factors
If a beam and heavy rigging are used to lift the tank car without contacting the jacket, then the jacket is protected, but the rigging becomes very heavy and reduces crane lifting efficiency
Solution Approach 1:
The lifting apparatus uses thin-walled curved arms that are structurally efficient yet lightweight. These arms are designed to be just thick enough to handle the lifting loads while remaining thin enough to minimize overall weight, achieving a optimal balance between strength and weight that conventional rigid beams cannot match.
Solution Approach 2:
The curved geometry of the arms provides structural efficiency by distributing stresses along the curved path, allowing the use of lighter materials and thinner walls compared to straight rigid beams. The curved shape naturally resists bending moments and distributes loads more effectively, reducing the overall weight of the rigging system.
3Object-affected harmful factors
If steep angle rigging is used to avoid contacting the jacket, then the jacket is protected, but high lateral forces are imposed on the tank car bolster
Solution Approach 1:
The curved arms follow the natural contour of the tank car, allowing the rigging to attach at angles that are gentler with respect to the bolster. The curvature enables the arms to approach the lifting lugs from a direction that minimizes lateral force components, reducing the risk of bolster damage while still protecting the jacket.
Solution Approach 2:
The curved arms introduce a third dimensional aspect to the rigging configuration, wrapping around the tank car in an arc rather than using straight-line connections. This dimensional change allows the lifting forces to be applied more tangentially to the tank car surface, reducing lateral force components that would otherwise be imposed on the bolster.
4Ease of operation
If the lifting location is below the tank car's center of gravity, then the lifting lugs are accessible, but the crane loading condition becomes unstable
Solution Approach 1:
The curved arms extend upward along the tank car contour, effectively raising the attachment point of the lifting apparatus closer to the tank car's center of gravity. This vertical dimension adjustment, achieved through the curved geometry, improves the stability of the crane loading condition while still maintaining access to the lifting lugs located on the bolster.
Data Source
AI summary
A lifting apparatus for lifting a tank car is provided. The lifting apparatus can include a first arm to surround and not contact a tank car jacket and a second arm to surround and not contact the tank car jacket.