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Typical Applications of Multi-Part Slings
Following are some useful guidelines for selection of multi-part slings for large lifts:
- When sling body D/d Ratio is less than 10. Because of its construction, a 7- or 9-part helically laid sling may bend against a load in an arc 10 times the component rope diameter, rather than 20 times the sling body diameter. Thus, greater bending capability can be obtained than with a single-part sling body with comparable rated capacity.
- When extreme flexibility is required. Select a multi-part sling when the sling body must snug up tight to grip the load or when easy handling of the sling is desirable—for attachment to the load or for storage. A multi-part will be far more flexible than a single-part body of the same rated lifting capacity.
- Where the sling can damage the load. Multi-part slings conform to the load surface, spreading the applied force over wider area than single-part constructions—therefore, are less likely to cut into or distort hollow vessels and tanks. However, it is always wise to protect such loads with blocking, planks, etc.—which protect the sling, as well as the load.
- Where kinking is a problem. Large capacity single-part slings will sometimes “take a set” that impairs internal adjustment within the rope, thereby reducing future usefulness. Under such conditions, it is a sound practice to use a multi-part body. Similarly, if there is a tendency for kinks to form during handling of the sling, multi-part bodies will be greatly appreciated by the rigger.
SLING ANGLES in this catalog depart from the traditional method of vertical angles measured at the sling hook. It has long been the opinion of sling users that it is easier to measure a sling angle relative to the ground or horizontal. The method is the same whichever angle is used. When the horizontal angle is used, you must use the trigonometric side
of the horizontal angle. When the vertical angle is used, you must use the trigonometric cosine of the vertical angle.
High flexibility is achieved by braiding one or more wire ropes from a fabric for the sling body. Component ropes run continuously and are hand-tucked into sling body or secured with swaged sleeves.
Each sling is hand-fabricated by laying together one or more ropes in a helical manner so component ropes run continuously through the eyes and sling body. Ends are secured into the component rope by hand-tucked splices.
MULTI-PART slings are flexible, snug up tightly around the load in choker hitches and quickly regain shape after a lift. They also offer outstanding handling characteristics, particularly in the larger rated capacities. When loaded, stress is equally distributed to all rope parts in the sling body due to the helical manner in which ropes are laid together.
Braided slings are formed by continuously plaiting or braiding several ropes together to form the sling body and both eyes in a single fabrication operation. Ends of individual ropes are usually hand-tucked and spliced into component ropes of the body. Eyes are often seized or wrapped since eyes are not braided.
Braided slings are often selected where loads must be rolled or maneuvered, since the design creates friction to grip loads and resist rotation.