Each head holder 22 has a downwardly open recess 29, FIG 2, in {HEAD ~ direct communication} with the suction holes 30 in {TAIL ~ the mounting pins} 28 
Each head holder 22 has a downwardly open recess 29 , FIG 2 , in { HEAD ~ direct communication } with the suction holes 30 in { TAIL ~ the mounting pins } 28
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH