In a preferred embodiment of a device according to the invention, said positioning arm comprises {HEAD ~ a double working cylinder} to perform {TAIL ~ the movement} of the positioning arm 
to perform
In a preferred embodiment of a device according to the invention , said positioning arm comprises { HEAD ~ a double working cylinder } to perform { TAIL ~ the movement } of the positioning arm
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH