D = 5/8 (See fig. 6-28)
D2 = 5/8 X 5/8= 25/64
SWL = 3 X 25/64 x 1 ton = 75/64 x 1 ton=1.1719 tons
The SWL in pounds = 1.1719 x 2,000 pounds = 2,343.8 pounds
In the metric system, the formula for the safe working load for shackles is as follows:
SWL = .417 X D2 X 1 tonne
D2 = 1.59 X 1.59 = 2.52
SWL = .417 x 2.52 x 1 tonne
SWL = 1.05 tomes
NOTE: A hook or a shackle can actually lift more than these formulas allow. These formulas give you the safe working load UNDER ANY CONDITIONS.
Mouse shackles whenever there is danger of the shackles pin working loose or coming out due to vibration. To mouse a shackle properly, you take several turns with seizing wire through the eye of the pin and around the bow of the shackle. Figure 6-29 shows what a properly moused shackle looks like.
Figure 6-28. - Shackle diameter.
Figure 6-29. - Mousing a shackle.
Steelworkers are required to move and handle many steel beams and steel shapes. When off-loading steel from vehicles and storing for further use, beam clamps are much more practical than using slings or chokers, especially when the flanges are the only available parts of the load. Figure 6-30 shows three different types of beam clamps. View A shows a clamp designed for use on a beam with a flat flange, either an I or an H. The clamp in view B may be used on beams with a circular cross-sectional area or where only one side of the flange is accessible. View C shows a clamp that is useful for connection to a column with a snatch block attached. The clamps shown can all be fabricated in the shop or field.
Hooks, shackles, and beam clamps must have the rated capacities and SWL permanently stenciled or stamped on them. OSHA identification tags can be acquired at no cost from COMTHIRDNCB DET, Port Hueneme, California, or COMSECONDNCB DET, Gulfport, Mississippi. Metal dog tags are authorized providing the required information is stamped onto the tags.
Other devices used for moving equipment are as follows: spreader bars, pallets, jacks, planks and rollers, blocks and cribbing, and scaffolds.
Figure 6-30. - Types of beam clamps.Continue Reading