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