In hoisting with slings, spreader bars are used to prevent crushing and damaging the load. Spreader bars are short bars, or pipes, with eyes fastened to each end. By setting spreader bars in the sling legs above the top of the load (fig. 6-31), you change the angle of the sling leg and avoid crushing the load, particularly in the upper portion.
Spreader bars are also used in lifting long or oversized objects to control the sling angle, as shown in figure 6-32. When spreader bars are used, make sure you do not overload the end connection. A spreader bar has a rated capacity that is the same as hooks and shackles. A good rule of thumb is the thickness of the spreaders end connection should be the same as the thickness of the shackle pin.
Cargo pallets coupled with slings are an immense advantage on jobs that involve moving a lot of small items (fig. 6-33). Spreader bars can be used often to avoid damaging the pallet and the load. The pallet supplies a small platform on which a number of items can be placed and then moved as a whole instead of piece by piece. Palletizing is clearly easier and faster than moving each item by itself.
Commonly, packages of the same size are palletized together, and when shipped, remain on the pallet until they are used up. You may not have the luxury of having excess pallets at your job site;
Figure 6-31. - Using spreader bars.
Figure 6-32. - Spreader bar used with an oversized load.
Figure 6-33. - Cargo pallet.
however, you need to have several to work efficiently. One can be loaded as the prior loaded one is being lifted. After each pallet is unloaded, the hoist will return for reloading. With two pallets, you are able to maintain a steady flow of material. One set of slings will be able to handle any number of pallets.
To be able to place cribbing, skids, and rollers, you need to be able lift a load a short distance. Jacks are designed and built for this purpose. Jacks are also used for precise placement of heavy loads, such as beams, or for raising and lowering heavy loads a shortContinue Reading