while the boom is under load (fig. 12-15, view A). The
To check the accuracy of the boom angle
boom angle on lattice boom cranes is the angle between
indicator, place a 3-foot builders level on the
the center line of the boom (from the boom butt pins to
center boom section and raise or lower the boom
the boom tip sheave) and the horizontal while the boom
until the level indicates the boom is level
is under load (fig. 12-15, view B).
(fig. 12-16). At this point the boom angle indicator
Figure 12-15.—Boom angle configurations.
Figure 12-16.-Check accuracy of boom angle indicator.
12-8
