HOISTING

LEARNING OBJECTIVE: Upon completing this section, you should have a basic understanding of hoisting, handsignals used in lifting loads, and some of the safety rules of lifting.

In lifting any load, it takes two personnel to ensure a safe lift: an equipment operator and a signalman. In the following paragraphs, we will discuss the importance of the signalman and a few of the safety rules to be observed by all hands engaged in hooking on.

SIGNALMAN

One person, and one person only, should be designated as the official signalman for the operator of a piece of hoisting equipment, and both the signalman and the operator must be thoroughly familiar with the standard hand signals. When possible, the signalman should wear some distinctive article of dress, such as a bright-colored helmet. The signalman must maintain a position from which the load and the crew working on it can be seen, and also where he can be seen by the operator.

Appendix III at the end of this TRAMAN shows the standard hand signals for hoisting equipment. Some of the signals shown apply only to mobile

equipment; others, to equipment with a boom that can be raised, lowered, and swung in a circle. The two-arm hoist and lower signals are used when the signalman desires to control the speed of hoisting or lowering. The one-arm hoist or lower signal allows the operator raise or lower the load. To dog off the load and boom means to set the brakes so as to lock both the hoisting mechanism and the boom hoist mechanism. The signal is given when circumstances require that the load be left hanging motionless.

With the exception of the emergency stop signal, which may be given by anyone who sees a necessity for it, and which must be obeyed instantly by the operator, only the official signalman gives the signals. The signalman is responsible for making sure that members of the crew remove their hands from slings, hooks, and loads before giving a signal. The signalman should also make sure that all persons are clear of bights and snatch block lines.

ATTACHING A LOAD

The most common way of attaching a load to a lifting hook is to put a sling around the load and hang the sling on the hook (figure 4-36). A sling can be made of line, wire, or wire rope with an eye in each

Figure 4-36.-Ways of hitching on a sling.

end (also called a strap) or an endless sling (figure 4-37). When a sling is passed through its own bight or eye, or shackled or hooked to its own standing part, so that it tightens around the load like a lasso when the load is lifted, the sling is said to be choked, or it may be called a choker, as shown in figures 4-36 and 4-37. A two-legged sling that supports the load at two points is called a bridle, as shown in figure 4-38.

Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing