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Figure  12-4.-Crane  radius  measurement.
Figure 12-7.Limit of approach for power lines.

Equipment Operator Basic - Beginning construction equipment operators manual
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and provide power for either swinging the crane or traveling  the  crane. The  swing-travel  jaw  clutch requires the operator to engage a button or push a lever to  select  for  swing  or  travel  operations.  Other  models have a separate steering and swing lever, allowing both functions to be operated at the same time. Use caution when traveling with a crawler crane on and around slopes. Some older types of crawler cranes do  not  have  travel  brakes  and  power  could  be disengaged, causing the crawler to freewheel. On-the-job  maneuvering  is  easy  because  of  the small  turning  radius  of  the  crawler  crane.  Additionally, the crawler crane does not require the use of outriggers for stability, so it requires less room for setting up. On some  models  of  crawler  cranes,  the  tracks  can  extend outward,  providing  the  crane  with  more  stability. Crawler crane models, on which the crawler tracks can extend, are rated at 85 percent of the minimum weight that can cause the crane to tip at a specified radius with extendable tracks are rated at 75 percent. Crane radius measurement is measured from the center of rotation to the center of the hook after the boom deflects forward when under load, as shown in figure 12-4. Depending  on  the  make  and  model,  most  crawler cranes  have  a  360-degree  working  area.  This  working area is divided into operating areas called quadrants of operation. The   crane   capacity   is   based   on   the quadrants, such as for over the side, over the drive end, and over the idler end, for a crawler-mounted crane (fig. 12-5). The capacity of the crane may change when rotating a load from one quadrant to another. This information is provided on the crane load chart. Truck-Mounted Cranes The truck-mounted crane (fig. 12-6) consists of a truck  carrier  and  house  (upper  revolving  unit)  and  is categorized   under   the   82-00000   USN   number registration  series.    The  truck  carrier  can  travel  from the  basic  boom,  Crawler  models  that  do  not  have different  jobsites  at  20  to  35  mph. Figure  12-6.—Truck-mounted  crane. 12-3







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