The apparatus 1 or 2 wherein one of {HEAD ~ said gripping elements} is fixed and supported by {TAIL ~ a frame}, and the other of said elements is movably supported by said frame 
The apparatus 1 or 2 wherein one of { HEAD ~ said gripping elements } is fixed and supported by { TAIL ~ a frame } , and the other of said elements is movably supported by said frame
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH