The support arms are pivotally attached through {HEAD ~ rotary shafts}, which are individually mounted at opposite ends of {TAIL ~ each} of the support arms 
The support arms are pivotally attached through { HEAD ~ rotary shafts } , which are individually mounted at opposite ends of { TAIL ~ each } of the support arms
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH