The leveling apparatus can keep {HEAD ~ a horizontal level} of {TAIL ~ the upper swing structure} against an inclined ground 
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The leveling apparatus can keep { HEAD ~ a horizontal level } of { TAIL ~ the upper swing structure } against an inclined ground
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH