When the hook engages an object and {HEAD ~ the body} is lifted by {TAIL ~ the lifting device}, the body rotates and the guide rotates about the hinge so that the guide continues to extend vertically 
When the hook engages an object and { HEAD ~ the body } is lifted by { TAIL ~ the lifting device } , the body rotates and the guide rotates about the hinge so that the guide continues to extend vertically
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH