Chapter 1 Rigging The capacity rating of the weakest individual components in a rigging arrangement determines the lifting capacity of the whole arrangement.
Chapter 1 Rigging Stock material weight tables list the weights of common construction shapes per linear or area unit.
Chapter 1 Rigging The density of a material is used to calculate the weight of an object with a known volume.
Chapter 1 Rigging The complex shape of an object can often be broken down into multiple simple shapes. The areas or volumes of these individual shapes are then added together to determine the total area or volume of the complex shape.
Chapter 1 Rigging The weight of a steel sheet metal tank can be calculated by determining the total surface area of the tank and multiplying by the area unit weight of the material.
Chapter 1 Rigging A load must be lifted from directly over the center of gravity in order to maintain balance.
Chapter 1 Rigging The symmetry of a load is sometimes a visual clue to the location of the center of gravity.
Chapter 1 Rigging Balance can be checked by lifting a load slightly and checking to see if it is level.
Chapter 1 Rigging The vertical location of the lift points in relation to the center of gravity also affects the stability of a load.
Chapter 1 Rigging The relative distances of the lift points from the center of gravity determine their share of the load weight.
Chapter 1 Rigging Forged machinery or nut eyebolts are used in various rigging and lifting applications.
Chapter 1 Rigging Machinery eyebolts must be threaded into a load until the shoulder is tight up against the load surface.
Chapter 1 Rigging When used in rigging that applies angular forces, eyebolts must be turned until the loop is in line with the rigging.
Chapter 1 Rigging Regular-nut eyebolts use one to three nuts to secure the eyebolt against the load.
Chapter 1 Rigging Shoulder-nut eyebolts have a shoulder that can be placed tight up against the load surface but require a nut to secure the opposite end.
Chapter 1 Rigging Eyebolts have the greatest load capacity when used with vertical forces. The capacity at other angles is a percentage of the vertical working load limit.
Chapter 1 Rigging Working load limits at various angles are sometimes available from manufacturer tables.
Chapter 1 Rigging Sling types used in rigging and lifting applications include wire rope, fiber rope, webbing, round slings, and chain.
Chapter 1 Rigging Various rigging hardware is used with slings to attach slings to hoists, loads, and other slings.
Chapter 1 Rigging Slings are used in various arrangements depending on the size, shape, and weight of the load.
Chapter 1 Rigging When multiple slings are used, the sling angle affects the increased forces on the sling. Smaller sling angles result in greater sling forces.
Chapter 1 Rigging Sling angle load factors are used to calculate the affect of sling angle on the forces experienced by each sling.
Chapter 1 Rigging The angular force factor calculates the actual sling forces, which must be less than the sling capacity. The sling angle loss factor calculates a derated sling capacity due to sling angle, which must be greater than the portion of load weight supported by the sling. Either calculation accomplishes the same result.
Chapter 1 Rigging If angular forces cause a flexible load to buckle, a spreader bar can be added to the rigging to change the direction of the forces on the load.
Chapter 1 Rigging When calculating the distribution of load weight in sling arrangements with three or more legs, at least one of the legs is assumed to carry no load weight. As a result, the load is divided equally among the others legs.