cases, a drive chain reduction. In most lattice boomcranes, the engine is mounted in the crane house.COUNTERWEIGHT.— The counterweight onthe rear of the crane house creates additional stabilitywhen lifting loads. The counterweight rotates with thehouse as it swings. Most counterweights are removableto reduce the overall weight of the crane for transporting.Part of your prestart inspection is to check thecounterweight mounting.Lattice Boom BreakdownThe bridle assembly plays an important part whenchanging the length of the boom. If you forget todisconnect the boom pendants lines from the boom tip,and not connect the bridle assembly or pendant linesbehind the boom section you plan to remove or install,and you drive out the bottom pins, the top pins will actas a hinge and the boom will fall, as shown in figure12-23. If you make this mistake and a crew member isunder the boom, a tragedy could result, as shown infigure 12-24.WARNINGNEVER WORK UNDER A CRANEBOOM. Because so many accidents haveoccurred while personnel were changingbooms, some manufacturers have made aone-way connecting pin that can only beinstalled from the inside. This requires the pinto be removed only from the outside, keepingpersonnel from getting underneath the boom(fig. 12-25). A common practice in the NCF isto install the pins from the inside out to preventpersonnel from maneuvering inside the boomto drive out the pins.Several methods are used to break down latticebooms to add or take out sections. If the boom sectionsFigure 12-24.-Never work under a crane boom.Figure 12-25.-Drive pins from the outside in.are bolt-connected, you must use dunnage for supportunder each section.The most common boom connection is with pins.To break down a pin-connected boom, make sure youFigure 12-23.—Incorrect way to disconnect the lattice boom.12-12
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