As a result of this arrangement, {HEAD ~ rotations} of the arm 12 about the axis 9 lengthen or shorten {TAIL ~ each helical cord} 
As a result of this arrangement , { HEAD ~ rotations } of the arm 12 about the axis 9 lengthen or shorten { TAIL ~ each helical cord }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL